·No text on this page.

·A Key to the Universe .. *Today most newspaper readers know vaguely that Einstein had something to do with the atomic bomb; beyond that his name 13 simply a synonym for the abstruse eren many a college graduate ... does not know that Relativity over and above its scientific import, comprises a major philosophical system which augments and illumines the reflections of Locke, Berkeley and Hume. Consequently, he has very litile notion of the vast, arcade, and mysteriously ordered universe in which he duelis This is a brilliant, readable ar.d clear report, by a gifted journalist, of the significance of Einstein's theartcs and their far reaching effect upon the modern world. Wrinca for Jaymen, it penetrates the realms of space, explains the facts available on the nature of atoms, and merges for purposes i clarity, the relation between philosophy and modern setence Uning the theories of Newton, Planck, Gamow, Lemaitre and Jeans, Bamelt explains the Einstein concept of the Universe. Relating these scienufic theories to the phila Onophical systems existing at the time, he shows how all forms of buman activity are influenced by the discoveries of science, and how Einstein's theories are a slep in this long history of research Trequently called an atheist by those who have fauled to grasp the meaning of his philosophy, Einsteia sumself is strongly convinced of the creation of the universe by a Supreme Intelligence. He says, "The most beautiful and most profound emotion we con erperience is the sensation of the mystcut. It is the power of all true science ... To know ther what is impenetrable so us really exists, mam- Jesting itself as the highest wisdom and the most radiant beauty which our du focieties can comprchend only its iherr most prinutive forms--this knowledge, thts feeling. u at the center of true religiousness." Albert Einstein ·Otlicr MIENTOR Books of interest Only 35€ each THE BIRTH AND DEATU OF THE SUN (newly revised) George Gamoio. A lucid explanation of stellar evolution and atomic energy, tracing the anatomy of matter as modern physics has explored » Hasrated. (#277) THE WORLD OF COPENYICUS (Sun, Staud Thou Stil) Angus Armitage. The fascinating story of the man who claimed the earth moved around the sun and proved it. (#3165) SCIENCE AND THE MODERN WORLD Alfred North hute. hend. A penetrating study of the infuence of four centuries of scicatric thought on world civilization. (128) NEW HANDBOOK OF THE HEATENS (abridged) Bern. hard, Bennett, and Rice. A practical, fascinating guide to the stars, planets and comets Blustrated. (#M152) Or US DERSTANDING SCIENCE James B Conant. The President of Harvard Vanersity explaias the scope of science in our modern world, and gives an hustorical view of its growth (168) TO OUR READERS We welcome your comments about SioNET and MENTO books, as well as your suggestions for new reprints. If your dealer does not have the books you want, you may ordet them by mail, enclosiag the hst price plus 5c a copy to cover mailag costs Send for a copy of our complete Catalogue. The New Amencan Library of World Litera tuse, loc., 501 Madison Avenue, New York 22, New York.

·THE UNIVERSE
AND
DR. EINSTEIN
By
LINCOLN BARNETT
With a Foreword by
ALBERT EINSTEIN
WILOR
A MENTOR BOOK
Published by THE NEW AMERICAN LIBRARY

·COPYRIGHT, 1948, BY HARPER & BROTHERS
COPYRIGHT, 1948, BY LINCOLN BARNETT
REVISED EDITION, COPYRIGHT, 1950,
BY LINCOLN BARNETT
Published as a MENTOR BOOK
By arrangement with William Sloane dssociates
FIRST PRINTING, MARCII, 1952
SECOND PRINTING, JULY, 1952
MENTOR BOOKS are published by
The New American Library of World Luterature, Inc.
501 Afadison Avenue, New York 22, New York
PRINTED IN THE UNITED STATES OF AMERICA

·No text on this page.

·No text on this page.

·Acknowledgment For Their Help and Advice in the Preparation of this book I wish to thank Dr. Allen G. Shenstone and Dr. Valentin Bargmann of the Department of Physics, Princecon University; Dr. Hermann Weyl of the Institute for Advanced Study, Princeton, N. ).; and Dr. H. P. Robertson of the California Institure of Technology I also wish to express my appreciation to Dr Harlow Shupley of the Harvard Observatory, who read the original manuscript and made valuable suggestions and criticisms, with particular reference to the sections dealing with astronomy. love my very special grantude to Dr. William \t' Haveas, fr, of the Department of Physics, Columbia University, who read and checked both the original manuscript, prior to its publication in Harper's magazine, and the crpanded version that appears here; and who pariently and cordially contributed his time and knowledge to the solunon of many difficulties presented by the exposiuon of this matcrial.

·No text on this page.

·Foreward by Albert Einstein Anyone Who Has Ever Tried to Present a rather abstract scientific subject is a popular manner knows the great difficulties of such an Ittempt. Either he succeeds in being intelligible by concesling she core of the problem and by offering to the seades only superficial aspects or vague allusions, thus deceiving the reades by acousing in him the deceptive illusion of comprehension, or else he gives in expert account of the problem, but in such a fashion that the untrained reader is unable to follow the esposition and becomes discoursged from reading any further. If these two categories are assicced from caday's popular scientific literature, surprisingly kcile remains. But the little thar is left is very valuable indeed. It is of great importance that the general public be gives an opportunity to experience-consciously and intelligently the efions and results of scientific research. It is not sufhcient that each result be taken up, cłaborated, and applied by a few specialists in the field. Restricting the body of knowledge to a small group dcadens the plulosophical spirit of a people and leads to spiriturl poverty. Lincoln Burnett's book represents a valuable contribution to popular scientific Ticing. The

·No text on this page.

·Foreword by Albert Einstein Anyone Who Has Ever Tried to present a rather abstract scientific subject in a popular manner knows the great difficulties of such an attempt. Either he succeeds in being intelligible by concealing the core of the problem and by offering to the reader only superficial aspects or vague allusions, thus deceiving the reader by arousing in him the deceptive illusion of comprehension, or else he gives an expert account of the problem, but in such a fashion that the untrained reader is unable to follow the exposition and becomes discouraged from reading any further. If these two categories are omitted from today's popular scientific literature, surprisingly little remains. But the little that is left is very valuable indeed. It is of great importance that che general public be given an opportunity to experiencem consciously and intelligently the cfforts and results of scientific research. It is not sufficient that each result be taken up. elaborated, and applied by a few specialists in the field. Restricting the body of knowledge to a small group deadens the philosophical spirit of 3 people and icads to spiritual porerty. Lincoln Barnent's book represents 3 valuable coninbution to popular scientific writing. The

·No text on this page.

·No text on this page.

·No text on this page.

·Carved in the white walls of the Riverside Church
in New York, the figures of six hundred great men
of the ages-saints, plulosophers, kings-stand in
limestone immortality, surveying space and time
with blank imperishable eyes. One panel cnshrines
the geniuses of science, fourteen of them, spanning
the centuries from Hippocrates, who died around
370 R C., ta Albert Einstein, who was seventy years
oll in March 1949. It is noteworthy that Einstein is
the only living man in this whole sculptured gallery
of the illustrious dead
It is equally noteworthy that of the thousands of
people who worship scekly at llanhattan's most
spectacular Protestant church, probably 99 per cent
would be hard pressed to explain why Einstein's
image 15 chore. It is there because a generation ago,
when the iconography of the church was being
planned, Dr. Harry Emerson Fosdick wrote letters
in a group of the nation's leading scientists asking
then to submit lists of the fourteen greatest names
in scientific history. Their ballots varied, Slost of
flict included Archimedes, Euclid, Galilco, and
Nonton. But on cuery list appeared the name of
Albert Einstein.
The 17st gap that has persisted for more than
forty ycars.sinec 1905, when the Theory of

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN inc realizes that virmally all the phenomena of nature are produced by these tsro primordial forces. C'ntil a hundred years ago electricity and magnetism while known and studied since carly Greek tincs-were regarded as separate quantities. But the crperiments of Oersted and Faraday in the ninerccnth century showed that a current of electricity is always surrounded by a magnetic field, and convessely that under certain conditions magnetic forces can induce electrical currents. From these erperiments come the discovery of the electromagneuc field through which light waves, radio waves, And all other electromagnetic disturbances are prop agated in space. Thus electricity and magnetism may considered as a single force. Save for graviration, nearly all other forces in the marcrial universe frictional forces, chemical forces which hold atoms together in molecules, cohesive forces which bind larger particles of mattes, classic forces shrich caisse bodies to maintain their shape-are of electromagnetic origin, for all of these involve the interplay of matter, and all matter is composed of TCOTTIS which in turn are composed of clectrical particles Ver the similarities berween gravitational and electromagicric phenomena are very striking, The planets spin sn the gravitational field of the sun; clections swirl in the electromagnetic field of the atomic nucleus. The carth, moscover, is a big mag- MC-- fkcular fact which is apparent to anyone who has ever used a compass. The sun also has a iniqneric field. And so hare all the stars. Although many attempts have been made to 15

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN nature no more is known to the modern scientist chan to Thales of Alietus, who first speculated on the electrification of amber around $85 B.C. Most concemporary physicists reject the notion that man ctn crer discover what these mysterious forces "really are. Electricity, Bertrand Russell says, "S in not a thing, like St. Paul's Cathedral; it is a way whicle things bekave. IVhen we have told how shings bcllaye whes they are electrified, and under what circumstances they are electrified, we have sold all there is co rell." Until recently scientists would have scorned such a thesis Aristotle, whose natural science dominated Vester thought for two thousand years, believed that man could arrive at an understanding of wanate rezlity by reasoning from self-ccident prsnciples. It is, for example, a self-evin dent principle that everything in the universe has proper place, hence one can deduce chat objects . fall to the ground because that's where they belong, and smoke goes up because that's where it belongs. The goal of Aristotelian science 1.5 to explain by things happen. Modem science was born wher Galileo logu trying to explais bow things happen and thus origsaled the method of controlled experi- **030 which now forms the basis of scientific investisation, Out of Galileo's discoveries and those of Newton in the nere generation there evolved a mechanical unircise of forses, pressures, tenisons, oscillauonsa and wascs There seemed to be no process of nature which could not be described in terms of ordinary cxperience, illustrated by a concrete model or pre-

·No text on this page.

·The factors that first led physicists to distrust their faith in a smoothly functioning mechanical universe loomed on the inner and outer horizons of knowledge-in the unseen realm of the atom and in the fathomless depths of intergalactic space. To describe these phenomena quantitatively, two great theo: rctical systems were developed between 1900 and 1927. One was the Quantum Thcary, dealing with tric fundamental units of matter and energy. The osher was Relativity, dealing with space, time, and thic structure of the universe as a whole. Both are now acccpred pillars of modern physical shought. Both describe phenomena in their fields in terms of consistent, mathematical relationships. They do not answer the New conian "how" any more than Newton's laus answered the Aristotelian "why." They provide equations, for example, that define with great accuracy thc law's governing the radiation and propagation of light. But the actual mechanism by which the atom radiates light and by which light is propagared through space remains one of nature's supreme mysteries. Similarly the laws governing the phenomenon of radioactivity enable scientists to predict that in a given quantity of umnium a certain number of atoms will disintegrate in a certain length of time. But just which 19

·THE UNIVERSE AND DR. EINSTEIN
dicted by Newton's amazingly accurate laws of
mechanics. But before the turn of the past century
certain deviations from these laws became apparent,
and though these deviations were slight, they were
of such a fundamental nature that the whole cdifice
of Newton's machine-like universe began to copple.
The certainty that science can explain bow things
trappen began to dim about twenty years ago. And
right now it is a quescion whether scientific man is
in touch with “reality" at allmor can crer hope to
be.

·THE UNIVERSE AND DR. EINSTEIN "I am able to prove," wrote the German great athematician, Leibnitz, "chat not only light, color, at, and the like, but mocion, shape, and extension hre were apparent qualities." Just as our visual itse, sor example, tells us that a golf ball is arhite, o vision abetted by our sense of touch tells us that r is also round, smooth, and small- qualities that ale no more reality, independent of our senses, than the quality which we define by convention as White. Thus gradually philosophers and scientists arrived at the starting conclusion that since every abject is simply the sum of its qualities, and since qualities Frist only in the mind, the whole objective universe of matter and energy, atoms and stars, does not exist except as a construction of the consciousness, an edifice of conventional symbols shaped by the senses of man. As Berkeley, the archenemy of materialism, phmased it: "All the chair of heaven and furniture of earch, in a word all those bodies which compose the mighty frame of the world, have not any substance without the mind. ... So long as they are not actually perceived by me, or do not exist in my. mind, or that of any other created spisit, they must cither have no etistence at all, or else subsist in the mind of some Eternal Spirir." Einscein carried this train of logic to its ultimate limits by showing that tuon spice and time art forms of intuition, which can no more bc divorced from consciousness than tin our concepts of color, shape, or size. Space las no objective reality except as an order or arrangement of the objects uc fccclc in ks, and time has 11 ·THE UNIVERSE AND DR. EINSTEIN atons will decay and how they are selected for doom are questions that man cannot yer answer. In accepting a mathematical description of nature, physicists have been forced to abandon the ordinary world of our experience, the world of sense perceptions. To understand the significance of this retrear it is necessary to step across the thin fine thar divides physics from metaphysics. Questions involving the relationshsp between ohserver and reality, subject and object, have haunted philosophical thinkers since the dawn of reason. Twenty-three centuries ago the Greek philosopher Deancritus wrore. "Sweet and bitrer, cold and warm as well as all the colors, all these things exist bur in opinion and not in reality; what really exists are unchangeable particles, atoms, and their motions in empty space " Galilco also was aware of the purely subicctive character of sense qualines like color, taste, smell, and sound and pointed out that "they can no more be ascribed to che exrernal objects than can the tickling or the pain caused sometimes by touching such objects." The English philosopher John Locke tried to penetrate to the "real essence of substances" hy drawing a distinction between what he termed the primary and secondary qualifics of marrer. Thus he considered that shape, motion, solidur, and all geometrical properties were real or prunary qualsties, inherent in the object itself, ulule secondary qualities, like colors, sounds, taster, ucre simply projections upon the organs of anise The artificiality of this distinction was obswus to later thinkers.

·THE UNIVERSE AND DR. EINSTEIN "I am able to prove," wrote the great German nathematician, Leibnitz, "that not only light, color, heat, and the like, but motion, shape, and extension too are mere apparent qualities." just as our visual sense, for example, tells us that a golf ball is white, sa vision abcuted by our sense of touch tells us that It is also round, smooth, and small-qualities that luse no more reality, independent of our senses, than the quality which we define by convention as litc. Tlus gradually philosophers and scientists arrived at the starting conclusion that since every object is simply the sum of its qualities, and since qualities crist only in the mind, the whole obiective universe of matter and energy, atoms and stars, does nor exist crcept as a construction of the consciousness, an edifice of conventional symbols shaped by the senses of man. As Berkeley, the archenemy of materialism, plırased it: "All the choir of heaven and furniture of carth, in a word all those bodies which composc the mighry frame of the world, have nor any substance withour the mind. ... So long as they are not actually perceived by me, or do nor exist in my: sind, or that of any other created spirts, they must cillier have no existence at all, or else subsist in the mind of sonic Eternal Spirit." Einstein carried this Crain af logic to vs ultimate limits by showing that cien space and time are forms of intucion, which can no more be divorced from consciousness than can our concepts of color, shape, or size. Space has nu objective reality except as an order or arrangement of the objects uc percene in it, and time has ·THE UNIVERSE AND DR. EINSTEIN no independent existence apart from the order of events by which we measure it. These philosophical subrietjes have a profound bearing on modern science. For along with the philosophers' reduction of all objective reality to a shadow-world of perceptions, scientists become aware of the alarming limitations of man's senses. Anyone who has ever thrust a glass prism into a sunbeam and seen the rainbow colors of the solar spectrum refracted on a screen has looked upon the whole range of visible light. For the human cye is sensitive only to the narrow band of radiation char falls between the red and the solet. A differencc of a few one hundred thousandths of a centimeter in ware length makes the difference berueen visibility and invisibiley. The ware length of red light is 00007 cm. and that of violec light 0000+ citi. But the sun also emits other kinds of radiation. Infrared rays, for example, with a vase length of 00008 0.032 cm. are pust z Intle {to long to excite the reana ro an impression of light, though the skin detects tlacis mpact as heat, Sumlarly ultraviolce ray's with a wire length of .00001 1000001 cm. ure too short for the eye to percente hur can be recorded on a photographic plare Phoevgraphs can also be xade by the "light" of x-rays wuch are cen shorter than ultraviolet and there are orher clectromagnetic wires of lewer med greater frequency—the gamma rays of radim, radio u zves, Cosmuc says-which can be detected in varS 235 and differ from light only 187 $are length It is cuj- 22 ·THE UNIVERSE AND DR. EINSTEIN dent, thereforc, that the human eye suppresses most of the "lights" in the world, and that what man can perceive of the seality around him is distorted and encebled by the limitations of his organ of vision. The world would appear far different to him if his ey'e were sensitive, for example, to X-rays, VISIEL LICHT swim WS MAU MUM us WAVELENGTH CENTIMETERS1 The clectromagnetic spectrum reveals the factox sangt tadication visible to man's eye From the standpoint of physics, the only difference between radio waves, visigle Inghi. wird such Yogh-frequency forms of radiation as X-rays and Am rasa kes in their wave length. But out of this vast range of ricctromagnetic radiation, egrending from cosmic rays with wavelengths of only one tnllionth of a centimeter up to infinitely long radio waves, the human eye selects only the Barrow band indicated in white on the above chart, Man's percepnons of the poiverse in which be dwells are thus restricted by the limitations of hus visual sense Wave lenght are ladicated on the chart by the deoary systers: 10.10 centimeters equals 10 x 10 x 10 equals 1,000; and 10 equals 1/10 11/10 x 1/10 equals 1/1,000. Realization that our whole knowledge of the unistrst is simply a residue of impressions clouded by our imperfect senses makes the quest for reality seem linpeless. If nothing has cristence savc in its being fucrceived, the world should dissole into an anarchy of individual perceptions. Bur 2 curious order cuas through our perceptions, as if indeed there might be an underlayer of objective reality which our ·THE UNIVERSE AND DR. EINSTEIN senses translate. Although no man can crer know Whether his sensation of red or of Aliddle C is the same as another man's it is nevertheless possible to 3ct on the assumption that everyone sees colors and hears tones more or less alike. This functional harmony of nature Berkeley, Descartes, and Spinoza attributed to God. Nodem physicists who prefer to solve their problems with: our recourse to God (although this seems to become more difficult all the time) emphasize that nature mysteriously operates on mathematical principles. It is che mathematical orthodoxy of the universe thar enables theorists like Csnstein to predict and dis.. cores natural laws simply by the solution of equa-:! tions. But the paradox of physics today is that with every improvement in its matherriatical apparatus the gulf between man the observer and the objective world of scientific descriprion becomes more profound. It is perhaps significant that in terms of simple magnitude man is the mean between macrocosm and microcost. Scaced crudely this means that 2 supergiant red star (the largest material body in the universe) is just as much bigger than man as an electron (tiniest of physical chuiries) is smaller. It is not surprising, therefore, that the prime mysteries of nature dwell in those realms farthest removed from sense-imprisoned man, nor that science, unable to describe the extremes of reality in the honely metaphors of classical physics, should content itself with noting such mathematical relationships as may be revealed. 24 ·3 The first step in science's retreat from mechanical explanation toward mathematical abstraction was taken in 1900, when Alax Planck pur forth his Quan- Cum Thicory to meet certain problems that had arisen in studies of radiation. It is common knowin cudge that when heated bodies become incandescent they eric a red glow that turns to orange, then yellow, then white as the temperature increases. l'sinstaking efforts were madc during the past cenkury to formulate a law stating how the amount of radiant energy given off by such hcared bodies saricd with warc length and temperarorc. All åttetnpts faited until Planck found by mathematical ficar ass equation that satisfied tfic results of experialone. The extraordinary feature of his equation was clue stressed on the assumption that radiant energy is wed not in an unbroken stream buc in discontinuous bits or portions ut hich he ternied quanta. Planck had no cridence for such an assumption, for no one know' anything (then or now) of the actual mechanism of radiation. But on purely theorrical grounds he concluded that cach quantur cutrics an amount of energy given by the equation Welt, where v is the frequency of the radiation anreis Planck's Constans, a small but incxorable nur : kr (roughly Ow000000000000000000000006024 ·THE UNIVERSE AND DR. EINSTEIN which has since proved to be one of the most fundamental constants in nature. In any process of radiation the amount of emitted energy divided bs, the frequency is always equal to 1. Although Planck's Constant has dominated the computations of atomic physics for half a century, its magnitude cannot be explained any more than the magnitude of the speed of light can be explained. Like other universal constants it is simply a mathematical fact for which no explanation can be given. Sir Arthur Eddington once observed thar any true law of nature is likely to seem irrational to rational min; hence Planck's quantum principle, he thought, is one of the few real natural law's science has revealed. The far-reaching implications of Planck's conjecrure did not become apparent till 1905, when Einstein, who almost alone among contemporary: physicists appreciated its significance, carried the Quantum Theory into a new domain. Planck had believed he was simply patching up the equations of radiation. But Einstein postulated that all forms of radiant energy-light, heat, X-says---Actually travel through space in separate and discontinuous quanta. Thus the sensation of warmth we experience when sitting in front of a fire results from the bombardment of our skin by innumerable quanta of radiant heat. Similarly sensitions of color arise from the bombardment of our optic nerves by light quanta which differ from each other just as the frequency » varies in the cquation Ehr. 26 ·THE UNIVERSE AND DR. EINSTEIN Einstein substantiated this idea by working out 2 - aw accurately defining a puzzling phenomenon known as the photoelectric effect. Physicists had been at a loss to explain the fact that when a beam of burc violet light is allowed to shine upon a metal blate the plate ejects a shower of electrons. If light of lower frequency, say yellow or red, falls on the plate, electrons will again be ejected but at reduced clocities. The vehemence with which the electrons LIGHT SOURCE ELECTRONS 00000000000000000 a D COOOOOOOOOOOOO0000 J.OO000000ODOCOCOOP METAL PLATE The photoelectric effect was interpreted by Einstein in 1905. When light falls on a metal plate, the plate cjects a shoner of electrons. This phenomenon cannot be explained by the classic wave theory of light. Esnstein deduced that light is not a continuous stream of energy but is composed of jodividual particles or bundles of energy which he called frosons When a photon strikes an electron the resulting acton is analogous to the impact of billiard balls, as shown in the simplified conception above. arc torn from the metal depends only on the color of the light and not at all on its intensity. If the light source is removed to a considerable distance and dimmed to a faint glow the clectrons that pop forth are ſcuer in number but their velocity is

·No text on this page.

·THE UNIVERSÉ AND DR. EINSTEIN ght thar cast only be erplained ly the wave theory. for ctample the shadous of ordinary objects like buildings, trees and telegraph poles appear sharply defined, but when a very firse svire or hair is held crxen a light source and a screen it casts no distinct shadow whatsoever, suggesting thar light rays bare lent around it just as waves of water bend around a small rock. Similarly a beam of light passing through a round aperture projects a sharplydefined disk upon a screen; but if the aperture is reduced so the size of a pinhole, then the disk beconus ribbed with alternating concentric binds of light and darkness, souncu Bar like those of a convenliunal rarge. This phenomenon is known as difiratrinn and has been compared with the rendency of Occan watcs to bond and diverge on passing through she narrow mouth of a harbor. If instead of one pin- Imle, cwo pinholes are employed very close together and side by side, the diffraction passerns seserge in 1 series of parallel shpes. Just 35 two wye systems meeting in a suaming pool will remforce wych exhics when crest concides with crest and innul each *hus sslicu the crest of one sase meets the trougls of emothes, so in the case of the adjacent pinlioles slie Ongli stripes occur where oso light waves rcinforce each other and the dark series s lcre tho ***es fisse interfered These plicnancna-diffracfor and interference are strictly wave charac- Icrisies and stould mat occur { lught ucre vif individual cachuscles. Hore than tuo centuries of experiment and thicory assert thau lige ?? CONist of 10 Ye Linstein's Photoclcctric Low dcup 29

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN light that can only be explained by the wae theory. For example the shadows of ordinary obiects like buildings, trees and telegraph poles appear sharply defined; but when a very fine wite of hair is heid Lietueen a light source and a screen it casts no distinct shadow whatsoever, suggesting that light rays hare bent around it just as waves of water bend around a small rock. Similarly a beam of light pussing through a round aperture projects a sharplydefined disk upoo a screen; but if che aperture is reduced to the size of a pinhole, theo thc disk ben cumes ribbed with alternating conccncnc bands of light and darkness, somewhat like those of a convenronal target. This phenomenon is hoown as diffracrion and has been compared with the tendency of ocean waves to bend and diserge on passing through the narrow mouth of a harbor. If instead of one pinslolc, tuo pinholes are employed very close rogerher and side by side, the diffraction pactems merge in a series of parallel stripes. Just as two ware systems iniccting in a swimming pool will reinforce each uther when crest coincides with crest and annul each orher when the crest of one wave meets the trough of another, so in the case of the adjacent pinholes thic bright stripes occur u bere exo light wires reinforce each other and the dark stripes where two staves have interfered. These phenomenaliffmction and interference are strictly wire charac- Iristics and would not occur if light were made upof indiridual corpuscles. More than two centuries of expxriment and theory assert that light must consist of wises. Yet Einstein's Photoclectric Lai

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN fivays a definite posicion in space; the electron apdcfiparently has not. A hard sphere takes up a very nice amount of room, an electron--well it is probably as meaningless to discuss how much roon an electron takes up as it is to discuss how much room 2 fear, an anxiety, or an uncertainty takes up." Shortly after de Broglie had his vision of "matter waves" a Viennese physicist named Schrodinger developed the same idea in coherent mathematical form, evolving a system that explained quantum phenomena by attributing specific wave functions {o protons and electrons. This system, known 35 "wave mechanics," was corroborated in 1927 when tivo American scientists, Davisson and Germer, proved by experiment that electrons actually do exhibic wave characteristics. They directed a beam of clectrons upon a metal crystal and obrained diffraction parterns analogous to those produced when light is passed through a pinhole. Their measurements indicated, moreover, that the wave length of an electron is of the precise magnitude predicted by de Broglie's equation, dah/78where v is the velocity of the electron, en is its mass, and b is Planck's Constant. But further surprises were in store. For subsequent experiments showed thac noc only electrons but whole atoms and even molecules produce wave patterns when difiracted by a crystal surface, and that their wave lengths are exactly what de Brogic and Schrodinger forecast. And so Acry'stal, because of the even and orderly arrangement of its can Doprot atoms and the closeness ot pets spacing, serves as a difracme grating for very short wart lengths, such as those of X-rays

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN crest is significant simply because it contains more molecules of water than the area you call a trough." Analogously Bom took the mathematical expression used by Schrodinger in his equations to denote wave function and interpreted it as a "probability" in a 'statistical sense. That is to say he regarded the intensity of any part of a wave as a measure of the probable distribution of particles at that point. Thus he dealt with the phenomena of diffraction, which hitherto only the wave theory could explain, in terms of the probability of certain corpuscles--- light quanta or clectrons---following certain paths and arriving at certain places. And so "waves of matter" were reduced to "waves of probability.” It no longer matters how we visualize an electron or an atom or a probability wave. The equations of Heisenberg and Born fit any picture. And we can, if we choose, imagine ourselves living in a universe of waves, a universe of particles, or as one facecious scicntist has phrased it, a universe of "waveicles."

·No text on this page.

·[ . THE UNIVERSE AND DR. EINSTEIN 1 crest is significant simply because it contains more molecules of water than the area you call a trough." Analogously Born took the mathematical expression used by Schrodinger in his equations to denote Ware function and interpreted it as a "probabilicy" in 3 scaristical sense. That is to say he regarded the intensity of asy part of a wave as a measure of the probable distribution of particles at that point. Thus he dealt wich the phenomena of diffraction, which hitherto only the wave theory could explain, in terms of the probability of certain corpascles light quanta or slectrossm-following certain parfis and arriving at certain places. And so "waves of marter" were reduced to “wares of probability." It no longer marters how we visualize an electron or an atom or a probabilicy wave. The equations of lleisenberg and Born fit any picture. And we can, if kc choose, imagine ourselves living in a universe of 14aves, (universe of particles, or as one facetious scientist has phrased it, a universe of "wareicles."

·No text on this page.

·While quantum physics thus defines with great accuracy the mathematical relacionships governing the basic units of radiation and matter, it further obscures the true nature of both, Alost modern physicists, houerer, consider it rather naive to speculate about the true nature of anything. They are "positivists" or "logical empircists"--who contend that a scientist can do no more than report his observations. And so if be performs two experia ments with different instruments and one seems to reveal chat ught is made up of particles and the other sliac leghe is made up of waves, he must accept both results, regarding them not as contradictory but as complementary. By utselt neither concept suffices to explain light, but together they do. Both are necessury to describe reality and it is meaningless to ask which is scally true. For in the abstract lexicon of quantum physics there is no such word as "really." It is fuule, moreover, to hope that the invention of more delicate tools may enable man to penetrate much farther into the microcosm. There is an indecerninsay about all the events of the atomic uniterse which refinements of measurement and obserration can never dispel. The element of caprice in atomic behavior cannot be blamed on man's coarsegrained implements. It stems from the very nature

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN rendered visible only by the high-frequency gamma rays of radium. But the photoclectric effect, it will be recalled, showed that photons of ordinary light exert a violent force on electrons, and X-rays knoc! them about even more roughly. Hence the impact of a still more potent gamma ray would prove disastrous. The Principle of Uncertainty asserts therefore that it is absolutely and forever impossible to determine the position and the velocity of an electron at the same time—to state confidently that an eleccron is "right here at this spor” and is moving at "such and such a speed." For by the very act of obscrving its position, its velocity is changed, and, conversely, the more accurately its velocity is determined, the more indefinite its position becomes. And when the physicist computes the mathematical mar. gin of uncertainty in his measurements of an cleo tron's position and velocity he finds it is always : function of that mysterious quantity-Planck' Constant, A. Quantum physics thus demolishes two pillars of the old science, causality and determination. For by dealing in terms of statistics and probabilities it abandons all idea that nature exhibits an inexorable sequence of cause and effect. And by its admission of margins of uncertainty it yields up the ancient hope that science, given the present state and clocity of cvery material body in the universe, can forccast the history of the universe for all time. One by-

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN prored. The aim of the practical physicist, there. fore, is to enunciate the laws of nature in ever more precise mathematical terms. Where the nincteenth century physicist envisaged electricity as a fluid ind, with this metaphor in mind, erolved the law's har generated our present electrical age, the twentieth century physicist tends to avoid metaphors. He knows that electricity is not a fluid, and he knows that such pictorial concepts as "waves" and "particles," while serving as guideposts to new discovery, must not be accepted as accurate representations of reality. In the abstract language of mathematics he can describe how things behave though he does not know need to know-what they are. Yet there are present-day physicists to whom thic void between science and reality presents a challenge. Einstein has more than once expressed the hope that the statistical method of quantum physics would prove a temporary expedient. "I cannot licficrc," he says, "that God plays dice with the world." He repudiates the positivist doctrine that science can only report and correlate the results of observation Ile believes in a universe of order and Garmony. And he believes that questing man may et attain a knowledge of physical reality To this end he has looked not within the atom, but outward the stars, and beyond them to the vast drowned Hepths of empty space and time.

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN proved. The aim of the practical physicist, thercfore, is to enunciate the laws of nature in ever more precise mathematical terms. Where tlie nineteenth century physicist envisaged electricity as a fluid and, with this metaphor in mind, cvolved the lau's that generated our present electrical age, the cuentieth century physicist tends to avoid metaphors. He knows that electricity is not a fluid, and he knows that such pictorial concepts as "waves" and "particles," while serving as guideposts to new discovery, must not be accepted as accurate represensations of reality. In the abstract language of mathematics he can describe how things behave though he does not know or need to know what they are. Yet there are present-day physicists to whom the void between science and reality presents a challenge Einstein has more than once expressed the liope that the statistical method of quantum physics would prove a temporary expedient. “I cannot be liere," he says, "that God plays dice with the world." He repudiates the positivist doctrine chac science can only report and correlare che results of obscrvation. Ile believes in a uniserse of order and Harmony. And he believes that questing man may yer arrain a knowledge of phys:cal reality. To this end he has looked not within the arom, but outward to the stars, and beyond them to the 435€ drowned depths of empty space and time.

·No text on this page.

·5 In his great treatise "On Human Understanding" philosopher John Locke wrote three hundred years ago “A company of chessmen standing on the same squares of the chessboard where we left them, we say, are all in the same place or unmored: though perhaps the chessboard has been in the meantimic carried out of one room into another, ... The chessboard, we also say, is in the same place if it remain in the same part of the cabin, though perhaps the ship which it is in sails all the while; and the ship is said to be in the same place supposing it kept the same distance with the neighboring land, though perhaps the earth has turned around, and so chessmen and board and shup have every one changed place in respect to remoter bodies" Embodied in this little picture of the moving but unmoved chessmen is one principle of relativityrelativity of position. But this suggests another idea --relativity of motion. Anyone who has ever ridden on a railroad train knows how rapidly another train flashes by when it is traveling in the opposite direction, and conversely how it may look almost motionless when it is moving in the same direction. A Fariation of this effect can be very deceptive in an enclosed station like Grand Central Terminal in New York. Once in a while a train gets under way

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN in more general terms: mechanical laws which are Fald in one place are equally valid in other place which moves uniforonly relative to the first. any -- The philosophical importance of this principlc lies in what it says about the universe. Since the aim of science is to explain the world we live in, is a whole and in al) its pares, it is essential to the scicnrise that he have confidence in the harmony of nature. He must believe that physical laws revealed to him on earth are in cruth universal lasus. Thus in relating the fall of an apple to the wheeling of the planers around the sun Newton hit upon a universal law. And although he illustrated his principle of relative morion by a ship at sca, the ship he actually had in mind was the earth. For all ordinary purposes of science the earth can be regarded as a stationary system. We may say if we choose that mountains, trees, houses, are at rest, and animals, auromobiles, and sirplanes move. But to the astrophysicist, the earth, far from being at rest, is whirling through space in a giddy and highly complicated fashion. In addition to its daily rotation about its axis at the rate of 1000 miles an hour, and its annual revolution about the sun at the rate of 20 miles a second, the earth is also involved in a number of other less familias gyrations. Contrary to popular belief the moon does not sevolve around the earth; they resolve around each othermor more precisely, around a common center of gravity. The entire solar system, moreover, is moving within the

·No text on this page.

·-- THE UNIVERSE AND DR. EINSTEIN had argued that the mere separation of bodies by listance proved the existence of a medium between them. And so eighteenth and nineteenth century physicists it was obvious that if light consisted of Waves, there must be some medium to support them, just as warer propagates the waves of the sea and ar transmits the vibrations we call sound. Hence when experiments showed that light can travel in a vacuum, scientists exoled a hypothetical substance called "erker" sshich they decided must pecvide all space and matter. Later on Faraday propounded another kind of ether as the carrier of çlectric and magnetic forces. When Maxtrell finally idemified light as an electromagnetic disturbance the case for the ether seemed assured. A universe permeated with an invisible medium in which the stars wandered and through which light traveled like vibrations in a bowl of jelly was the end product of Newtonian physics. It provided a mechanical model for all known phenomena of • nature, and it provided the fixed frame of reference, che absolute and immovable space, which Newton's cosmology required. Yet the ether presented certain problems, nor the least of which was that its actual existence had never been proved. To discover once and for all whether there really was any such thing 15 cther, two American physicists, A. A. Michelson and E W. Morley, performed a classic expetiment in Cleveland in the The principle underlying their experiment was year 1881,

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN quite simple. They reasoned that it all is simspace ply a motionless sea of ether, then the earth's motion through the ether should be detectable and measurable in the same way that sailors measure the velocity of a ship through the sea. As Newton pointed out, it is impossible to detect the movement of a ship through calm waters by any mechanical csperiment performed inside the ship. Sailors ascertain 2 ship's speed by throwing a log overboard and watching the unreeling of the knots on the log line. llence to detect the earth's motion through the erlier sea, Michelson and Morley threw a "log" overboard, and the log wis a beam of light. For if light really is propagated through the ether, then its relocny should be afíccted by the ether stream arising from the carth's movement. Specifically a light ray projected in the direction of the earth's movement should be slightly retarded by the ether flow, just is a swimmer is retarded by a current when going upstream. The difference would be slight, for the velociry of light (which was accurately determined in 1849) is 186,284 miles a second, while the velocity of the earth in its orbit around the sun is only 20 miles a second Hence a light ray sect against the criter stream should travel at the rate of 186,267 miles a second, while one sent with the ether stream should be clocked at 186,307 miles a second. With these idcas in mind Michelson and Morley constructed an instrument of such great delicacy that it could detect a variation of even a fraction of a milc per second in the enormous velocity of light. This instrument, which they called an "interfero.

·CLASS PIE 1 SOURY The Michelson-Morley interferometer consisted of an ar. fangement of mirrors, so designed that a beam transmitted from a light source (above left) was divided and sent in two directions at the same time. This was done by a mirror, A, the face of which was only thinly silvered, so that part of the beam was permited to pass through to mitor C (right) and the remainder reflected at right angles toward mirror B. Mirrors B and then reflected the rays back to mirror A where, reunited, they proceeded to an observing telescope T Since the beam ACT had to pass three times through the thickness of glass behind the reflecting face of mirror A, a clear glass plule of equal thickness was placed berscen A and B to infercept beam ABT and compensate for this retardaron. The whole apparatus as cotated in different directions so that the beams ABT and ACT could be sent with, ag318ist, and si right ongles to the postulated cther strcam At first glance a might appear that a trip "downstream," for example from 810 A, should compen. sale in time for an "apstream" trip from A to B But this is not so. To row a boat one side upstream and another mile downstrcam tales longer than towing two miles in sul warcr or across current, even with allowance for drift. Had there been any scceleration or ritardation of cuhet beam by the ether stream, the optical apparatus at T would have detected it, ·6 Among those who pandered the enigma of the Michelson-Morley experiment was a young patent office examiner in Berne, named Albert Einstein. In 1905, when he was just twenty-six years old, he published a short paper suggesting an answer to the riddle in terms that opened up a new world of physical thought. He began by rejecting the ether theory and with it the whole idea of space as a fixed system or framework, absolutely af rest, within which it is possible to distinguish absolute from relative motion. The one indisputable fact established by the Michelson-Morley experiment was that the vclocity of light is unaffected by the motion of the carth. Einstein seized on this as a revelation of uni. Scrsal law. If the velocity of light is constant regardless of the carth's motion, he reasoned, it must be constant regardless of the motion of any sun, moon, szar, meteor, or other system moving anywhere in tlle unii ersc. From this he drew a broader generalization, and asserted that the laws of nature are the same for all uniformly moving systems This simple statement is the essence of Cinstein's Special Theory of Relativity. It incorporates the Galilean Relativity Principle which stated that mechanical laws are the same for all uniformly mouing systems. But its phrasing is more comprehensne, for Einstein was

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN tivity stems from man's reluctance to recognize that sense of time, like sense of color, is a form of perception. Just as there is no such thing as color without an eye to discern it, so an instant or an hour or a day is nothing without an event to mark it, And just 3s space is simply a possible order of material objects, so time is simply a possible order of events. The subjectivity of time is best explained in Einstein's own words. "The experiences of an individual," he says, “appear to us arranged in a series of events, in this series che single events which we remcınber appear to be ordered according to the criterion of earlier' and 'later.' There exists, there." forc, for the individual, an l-time, or subjective ime. This in itself is not measurable. I can, indeed, issociate numbers with the events, in such a way chat a greater number is associated with the later cvent than with an earlier one. This association 1 can define by means of a clock by comparing the order of events furnished by the clock with the order of the given series of events. We understand by a clock something which provides a series of cients which can be counted." By referring our own experiences to a clock (or a calendar) se make time an objective concept. Yet the time intervals provided by a clock or a calendar are by no means absolute quantities imposed on the entire universe by divine edict. All the clocks ever nised by man have been geared to our solar system. What we call an liour is actually a measurement in spracc--un arc of 15 degrees in the apparent daily rotation of the celestial sphere. And what we call

·No text on this page.

·THE UNIYERSE AND DR. EINSTEIN ght rays that left their source in 1912. Whether acturus eren exists ow" nature forbids us to now until 1988, space and Despite such reflections it is difficult for earthbound man to accept the idea that this very intican which he calls "now" @noor apply to che universe as a whole. Yet in the Special Theory of Relativity Einsccin proves by an unanswerable sequence of example and deduction that it is nonsense to think of events taking place simultaneously in unrelated systems. His argument unfolds along the following lines. To begin with one must realize that the scientist, whose task it is to describe physical crents in objecrive terms, cannot use subjective words like "this," "besc," and "now." For him concepts cinc cake on physical significance only when the rclations between events and systems are defined. And it is constantly necessary for him, in dealing with matters involving compler forms of motion (as in celestial mechanics, electrodynamics, ctc.) to re- Lite the magnitudes found in one system with those OCCUTTING in another. The mathematical laws which define these relationships are known as laws of transformation. The simplest transformation may be illustrated by a man promenading on the deck of a ship if he walks forward along the deck at the rate of 3 miles an hour and the stup moves through the Sea at the rate of 12 mules an hour, then the man's clocity with respect to this sea is 15 miles an hour; if he walks aft his vclocky strive to the sea is of

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN ght rays that left their source in 1912. Whether Arcturus even exists "now" nature forbids us to now until 1988. space and Despite such reflections it is difficult for earthbound man to accept the idea that this very instant which lic calls "now" cannot apply to the universe as a whole. Yet in the Special Theory of Relaciriry Einstein proves by an unanswerable sequence of trample and deduction that it is nonsense to think of events taking place simultancously in unrelated systems. His argument unfolds along the following Imes. To begin with one must realize that the scientist, swhose task it is to describe physical events in objective terms, cannor use subjective words like "this." "here," and "now." For him concepts of time take on physical significance only when the relations between creats and systems are defined. And it is constantly necessary for him, in dealing with matters involving complex forms of motion (as in celestual mechanics, clectrodynamics, etc.) TO TClare the magnitudes found in onc system with those occurring in another. The matlieniatical laws which define these relationships are known as law's of transformation. The simplest transformation may be illustratcd by a man pronichading on the deck of a slip if he walks forward along the deck at the rate of 3 miles an liour and the ship nioves through the Sa at the rate of 12 miles an hour, then the man clocity warh respect to the sea is 15 miles an hour if he walks aft his clocity sclative to the sea is a 1 S

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN ommon center of gravity. Careful analysis of these noring systems has shown that the light from the approaching star in each pair teaches mith at precisely the same velocity as the light from the receding star. Since the velocity of light is a universai constant it cannot in Linstein's railway problem be affected by the velocity of the train. Even if we imagine that the train is racing toward the signal light at a specd of 10,000 miles a second, the prit ciple of the constancy of the velocity of light tells us tirat an observer aboard the train will still clock the speed of the oncoming light beam at precisely 186,284 miles a second, no more, no less. The dilemma presented by this situation involves much more than a Sunday morning newspaper puzzlc. On the contrary it poses a deep enigma of. nature. Einstein saw that the problem lay in the irrcconciable conflict between his belief in (1) the constancy of the relocuy of light, and (2) the prin. ciple of the adlition of velocities. Although the litter appears to rest on the stern logic of mathemuistics (ie, that two plus two makes four), Einstein recognized in the former a fundamental law of ruature. He concluded, therefore, that a new transformation rulc must be found to enable the scientist to describe the relations between moving systems in such a way that the results satisfy the known facts abour light. Linstein found what he wanted in a series of equations developed by the grear Durch physicise, H. A. 55

·No text on this page.

·M THE UNIVERSE AND OR, EINSTEIN common ceaser of gravity, Careful analysis of these moring systems has shown that the light from the approaching star in each pait reaches earth at preciscły the same velocity as the light from the receding star. Since the velocity of light is a universal constant is cannat in Einstein's railuay problem de affected by the velocity of the rain. Even if we imagine that the train is racing toward the signal light at a speed of 10,000 miles a second, the prin ciple of the constancy of the velocity of light tells us that an observer aboard the train will still clock the speed of che oscoming light beam at precisely 186,784 miles a second, no more, na less. The dilemsta presented by this situation inraites much more than a Sunday morning neurspaper puz, zic. On the contrasy it poses a decp enigma of nature, Einstein saw that the problems lay in the irreconcilable conflict desween his belief is (1) the constancy of the veincìty of light, and (2) the principle of the addition of velocities. Although she farter appears to rest on the stern logic of mathematics (1 con that two plus two makes four), Einstein recognized in the former a fundamental law of naturc. lle concluded, therefore, that a new trans formation rule must be found to enable the scientist to describe the relacions berween moring systems int such a way that the results satisfy the known facts alont üglit. Einstein (ound 1 har he wanted in a series of 1901- inns det claped by the great Durch physicist, H. A. 55

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN 573 Sashes may be regarded as simultaneous. Now crant roars down the track, and a second observer is sátting precariously perched atop one of the ors with a firror apparatus just like the one on the mbankment. It kappers that this moving observer finds himself directly opposite the observer on the embankment ar the precise instant the lighening bolis hit A and B. The question is will the lighting fashies 3ppear simultaneous to him? The answer is chey will not. For if his train is maring away from ligkming bole B and toward lighcaing balc A, then it is obvious that B will be reflected in his mirrors a fraction of a second later than A. Lest there be any doubt about this one may imagirte temporarily that the train is moving at the impossible rate of 186,287 mües a second, the rclocity of light. In that event flash B, traveling at precisely the same velocity as Sash A, will never be reflected in the mirrors at all because it will never be able to overtake the train So the observer on the train will assert that only one lightning bolt struck the crack, And whatever the speed of the train may be the moving observer will always insist that the lightning Rash ahead of him kas struck the track first. Hence the lightning Nashes which are simultaneous relative to the stationary observer are not sunuluineous relative to the observer on the irsin. The paradox of the lightning flashes thus dramatizes one of the subtlest and most difficu'r concepts in l'instein's philosophy the relativity of simultat ncíry. It shows that man canti assume that bis ·THE UNIVERSE AND DR. EINSTEIN Lorencz, in connection with a specific theory of his own. Although its original application is of interest now chiefly to scientific historians, the Lorentz' transformation lives on as part of the mathematical, framework of Rclarivny. To understand what is says, however, it is first necessary to percorre the Haus in the old principle nf the addion of velocities. These raus Linstein ponted out by mcans of still another way ancilors. Once agun he en. visaged a straighı length trach, rhis time with an observer sting on an embinhment beside it. thunderstor breaks, and mo kults of hightning strike the rrick simultancourts . separate purines, and B Varu, mis IMPLE Biorato e fit4E293 day "Sultanarul : les pisterna dhe du dropp***?y hic assumes (11.10 the wliseries «!!""f'ret'e' half way hercent 2012]}} ???!??!?cy":nul nech 39 irringument of murtun cuplate 4 ind it the wme (IT SH, Then of the lightning lishes hip?, server's murm a portarse's the } 1 56 ·THE UNIVERSE AND DR. EINSTEIN wo flashes may be regarded as simultaneous. Now a train roars down the track, and a second observer is sining precariously pecched stop one of the mars with a mirror apparatus just like the one on the embankment. It happens that this moving observer finds hirself diectly opposite the observer on the combankment at the precise instant the lightning Ixolts liie A and B. The question is: will the lightning Nashes appear simulraneous so him: The answer is: they will not . For if his train is moring away from lighcaing bolt B and toward lightning bolt A, then it is obvious that B will be reflected in his mirrors a fraction of a second later than A. Lest there be any Joubt about this, onc may imagine temporarily that the train is moving at the mpossible rate of 186,287 ssiles a second, the velocity of light. In that event fash N, traveling av precisely the same velocity as hixh A, will never be reflected in the mirrors at all because it will neser be able to overtake the train. So the observer on the train will assert that only one lightning bolt struck the track. And whatever the speed of the train may be the moving observer will always insist that the lightning dash ahead of him has struck the track first. Hence the lightning flashes which are simulcaneous relative to the stronity obsensor are not simultaneous relative to the The parador nf the lightning Bashes thus dramatoes te of the subtiest and merst difficuit concepts in Linister's philosophy the relativity of simulta siity. It shons that man eannot assume that hi olsenter on the tuin, ·THE UNIVERSE AND DR. EINSTEIN Lorentz, in connection with a specific theory of his own. Although its original application is of intcrest now chiefly to scientific historians, the Lorentz transformation lives on as part of the mathematical framework of Relativity. To understand what it says, however, it is first necessary to perceive the flaws in the old principle of the addition of veloci ties. These fan's Einstein pointed out by means of - still another railway ancedore. Once again luc cnvisaged a straight length of track, this time with an observer sitting on an embankment bcsidc it. thunderstorm brcaks, and two bolts of lighting serike the track simultancously a separate points, Kamer A and B. Now, asks I insun, har de sc mcan liyo "simultancously"" To down this delinition he assumes that the observer a string percenscly hilf svay between A and I, and that he nn capuppxed us ith an arrangement of mitos s uks enable loro scc A and B at the same time unhout wing fus Cies. Then if the lightning flashes are retlercei in the obs. server's murrors at precisely the same p!!! 211, the ·THE UNIVERSE AND DR. EINSTEIN according to the rclocity of each system of refernice. So although Lorentz had originally developed his cquations to meet a specific problem, Einstein made them the basis of a tremendous generalization, and to The Loreru transformation relates distances and times observed ON TO 10% syetemis sith those observed on systems telatively at test Suppore, for erample, that a system, or reference body, 13 moving in a certain directos, then according to the old prinapit of the addition of telocities, a distance of length *', measured with respect to the moving system along ibe direction of motion, is related to teszths, measured with respect to a relatively statiosary system, by the equation=1 where is the velocity of the raovine stem and is the time Dimensiops y and, measured #ith respect to the moving systems at right angles tox' and at night ingles to each otber (1.c., height and breadth), are related to dimen. 30 y and on the relatively stationary system by y = y, 2018 1. And Onally a lume interval t', clocked with respect to the moving bystem, is related to time interval , clocked with respect to the relatively stationary system, by ello other words, dusuances and times are pot afected, in classical Physics, by the velocity of the system is question But 16 this presupposition which leads to the paradox of lke bgt ning Aashes The Lorentz transformation rdate the distances and times obsersed on moling systems to the conditions of the stationary ob-erser, keeping the vtlooy of light ca consant for all observers Here are the equauch of the Lorentz Esaselormation which bave supplanted the older and evidently inadequate relation-Dipy died abole * te noted that, 15 19 the old transloration Law, dimensors are usatisies moestyon 11 Balso be ken that ne Velocity of the moving him to smalt relate to the relocity of light, then the equations of the Lord translarmation til hit them ches to the relations of the oll principle of the addimm of Iclock Bul as the magnitude of voproaches that of c, Thibe value of t'andrare radically changed

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN according to the velocity of each system of refer- Ince. So although Lorentz had originally developed his cquations to meet a specific problem, Einstein made them the basis of a tremendous generalization, and to The Lorent transformation relates distances and times observed DA Mosing syslems with those observed on systems telatively at rest. Suppose, for example, that a sistem, or reference body, 19 morins in a certain direction, then according to the old principle ol the addition of selectes, a distance or length ', measured with Inspect to the moving system along the direction of motion, is re- Lated to length, Deatured with respect to a relatively stationary ryslem, by the equation zu bere v is the velocity of the moving system and is the time. Dimensions and measured with respect to the moving system at right angles tox' and at nght angles to each oibes (.e., beight and breadth), are related to dingen. alons y and : on the relatively stationary system by 'y, and :'=: And lipally a ume interval t", clochert with respect to the trouing syetem, is related to time interval 1, clocked with respect to the relatively stalsonaty system, by I' = . In other words, dilunces ay times are not accted, in clasucal Physics, by the veloaty of the ystem in question But it this presupposi'non sthich leads to the porajosojile lighting Aashes. The Lorentz transformation Tedures the distances and times observed on moving systems to the conditions of the stationary observet, keeping the velocity of light C* Constart for all obrers lere are the equations of the Lorentz transformation which hase supplanted the older and evidently inaleguate relationships in above -rt V1) 1- (rin) Vi (1? s?) I'!' te noted that, as in the Gli transforsalon lax, dicenpº' and ' art unattesimal i molian It will also be xen that 11tte velocity of the moving (stum va small relating to the Erkkuly all. bt , then the equation of the Lartott inn fortauon Te ke ibericles to the futions of the old principle of the add.. trona sekitic fu! the magnitude of approaches that of c. team of tard are tad.cally changed ·THE UNIVERSE AND DR. EINSTEIN subjective sense of “noir" applies to all parts of the universe. For, Einstein points out, "every reference body (or coordinate system) has its own particular time; unless we are told the reference body so which the statement of timc refers, there is no meaning in 2 statement of the time of an cvent." The fallacy in the old principle of the addition of velocities lies therefore in its tacit assumption that the duration of an event is independent of the state of notion of the system of seference. In the clc of the man pacing the deck of a ship, for cumple, it was 36- sumed that if he walked three miles in inc hour as timed by a clock on the moving sluip, his rute would be just the same timed by a stacionary clock 3nchored somchow in the sca. It was further assumed that the distance he cruscrsed in one hour would have the same value whether ! W measured rela. tive to the dech of the shup (the muning stem) or relative to the ca (the starts stein) This constiturcs a second fillies in the hell of clocincs --for distance, like time, is relaxene concepe, and there as no such shingas ? yoksare il independent of the state of morm of the son of rcícrenrc. Einstcin asserrcut, the retur&', che attic YUICHIY who wishes to describe the file 13011 *** ! ature in tcrme that are consistent for all set throughout the universe must regard illcarcaci?n mic and distance as variable quantities The Art 174 compris. ing the Lorent 17311538*** ******* **** They preserve the clocity of light » rumental constant, but modify all incusurments of time us! Jestants 58 ·= These truths can be described in very concrete scrms. For once he had evolved the philosophical - and mathematical bases of Relativity, Einstein had to bring them into the laboratory, where abstractions like time and space are harnessed by means of clocks and measuring rods. And so translating his basic ideas about time and space into the language of the laboratory, he pointed out some hitherto unsuspected properties of clocks and rods. For example: a clock attached to any moving system runs at a different rhythm from a stationary clock; and a mcasuring rod attached to any moving system changes its length according to the vclocity of the system. Specifically the clock slows down as its velocity incrcases, and the measuring rod shrinks in the direction of its motion. These peculiar changes have nothing to do with the construction of the clock or the composition of the rod. The clock can lc a pendulum clock, 3 spring clock, or an hour plass The measuring rod can be a wooden ruler, a metal yardsrick, or a ten-mile cablc. Thic slowing of the clock and the contraction of the rad are not mechanical phenomena; an observer riding along with the clock and the measuring rod would not nočice these changes But a stationary observer, i.c.- stationary relative to the moving system, would fine ·THE UNIVERSE AND OR. EINSTEIN the edifice of Relatuy added another axion: the laws of nature preserve their uniformity in all sysu tems when related by the Lorentz transformation : Stated those in the abstract language of mathematics the significance of this mom n screcly lie appare cnt to the li) 11.11 Pur ilt passie's 111 cquution is never a pure abstraction. It pl a hand of shorehand Yenion uhh the x im dinlenmenicnt to describe the pleasuomens e f ? tue sometimes it is also a Rosetta Stone' in ulud the theoretical phy's. icre c.in decipher secret redan vot horu lodge. And so by duluction from the message written in the equur:(0338 «f the 1x693.03 210m, l instein disconcret i punde set on Je Tasarruny truths tucant the pare ne ·THE UNIVERSE AND OR. EINSTEIN and that a clock keeps the same rhythm in morion and at rest. Common sense dictates that this must be 50. But as Einstein has pointed out, common sense is actually nothing olore than a deposit of prejudiccs laid down in the mind prior to the age of eighteen. Every new idea one encounters in later years must combat this accretion of "self-evident" concepis. And it es because of Einstein's unwilling-. ness ever to accept any uoprosen principle as selfcvidene ekst he was able to penetrate closer to the underlying rcalities of nature than any scientist ben fare him. (l'hy, he asked, is it any swore strange co assung dut moving clocks slaw down and moving rods contract, than to assume that they don't? The reason classical physics cook the latter view for granted is that man, in his everyday experience, rcver encounters relocties great enough to make these changes manifest. In an automobile, an airplasse, cren in 3 V-2 rocket, the slowing down of a which is issacasurable. It is only when velocities approximac thic of ligke that relativisac effects can be detected. The cquisions of the Lorentz fransformation show very plainly that at ordinary speeds the modification of tune and space intervals amounts practically ro zero. Relativity does not therefore contradict classical physics. Ir simply regards the ald concepts as lunited cases that apply soicly to the (anuluar experiences of man. --- Linssin thus surinounts the barrier rcared by man's mpulse to define reality solely as he ormai...

·No text on this page.

·THE UNIVERSE AND OR. EINSTEIN with the predictions of Linstein's cquations. Someday science may devise a far more interesting test of the same principle. Since any periodic motion serves to measure time, the human heart, Einstein has pointed out, is also a kind of clock. Hence, ac. cording to Relativity, the heartbeat of, a person traveling with a velocity close to that of light would byc relauvely slowed, along with his respiration and all other physiological processes. He would not 80- tice this retardation because his watch would slow down in the same degree. But judged by a stationary timekeeper he would "grow old" less rapidly. In a Ruck Rogers reain of ſancasy, it is possible to imagine some future cosmic explorer boarding an atom-propelled space ship, ranging the void at 167,000 miles per second, and returning to earth after ten terrestrial years to find himself physically years older. only five

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN with the predictions of Einstein's equations. Someday science may devise a far more interesting rest of the same principle. Since any periodic motion Serres to measure time, the human heart, Einstein has pointed out, is also a kind of clock. Hence, 1ccording to Relativity, the heartbeat of a person traveling with a velocity close to thac of light would he relatively slowed, along with his respiration and all other physiological processes. He would not non tice this retardation because his watch tonld slow doun in the same degree. But judged by a station ary timekeeper he would grow old" less rápidly, In a Buxt Pagar realm of fireasy, it is possible to imagine some future cosmic crplorer boarding an stom-propelled space ship, ranging the void ac 161,000 miles per second, and returning to earth after ten terrestrial years to find himself physically only five years older.

·No text on this page.

·8 of mass. order to describe the mechanics of the physical universe, thrçc quantities are required: time, dis- Cance, and mass. Since time and distance are relasivc quintitics one might guess that the mass of a body also varies with its state of motion. And indeed the most important practical results of Relacivity have arisen from this principle--the relativity In its popular sense, “mass" is just another word for "weight." But as used by the physicist, it dem notes a rather different and more fundamental prop cry of matter namely, resistance to a change of motion. A greater force is necessary to move a freight car than a velocipede; the freight car resists motion more stubbornly than the clocipede because it has greater mass. la classical physics the miss of any body is a fixed and unchanging prop crty. Thus the mass of a freight car should remain the same whether it is at rest on a siding, rolling across country at 60 miles an hour, or hurtling through outer space at 60,000 miles a second. But Relarıvıy assents that the mass of a moving body is ly no means constant, but increases with its velocity, Ilic old pluysies (ailed to discover this fact siinply because man's senises and instruments are 100 crude to norc thic infinitesimal increases of mass pro-

·No text on this page.

·8 In order to describe the mechanics of the physical universe, three quantities are required: time, discancc, and mass. Since time and distance are relative quantities onc might guess that the mass of a body also raries with its state of motion. And indeed the most important practical results of Relativity have arisen from this principle--the relativity of muass. In its popular sense, "mass" is just another word Cor "ucight." But as used by the physicist, it denotes a rather different and more fundamental prop crty of matter namely, resistance to a change of motion. A greater force is necessary to move a freight car than a clocipede; the freight car resists motion more stubbornly than the velocipede because it has srcater mass. Ia classical physics the inass of any body is a fixed and unchanging prop- Thus the mass of a freight car should rernain the same whether it is at rest on a siding, rolling across country at 60 miles an hour, or hurtling through ourer spice at 60,000 miles a second. But Rclmity asserts that the mass of a moving body is lix no means constant, but increases with its veloctry. The old physics failed to discover this fact simply because man's senses and instruments arc too crude to note thic infinitesimal increases of mass pro-

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN fruitfully applied by experimental physicists, Electrons moving in powerful clectrical fields and deci gerticles cjccted from the nuclei of radioactive sub. Stanicas antsin sclocities ranging up to 99 per cent ther of light. For atomic physicists concerned with tlicse gocat speeds, the increase of mass predicted by Relativity is no arguable theory bar an empirical. fact their calculations cannot ignore, In fact the mechanics of the proton-synchrottaa and other new super-Cresey machines are designed to allow for the increasing mass of particles as their speed approaches the velocity of light, By Surther deduction from his principle of Relativity of mass, Einstein arrived at a conclusion of incalculable mportance to the world. His train of Seasoning ran somewhat as follows: since the mass of a noring body incrcascs as its motion increases, and since motion is a form of energy (kinetic energy), then the increased mass of a moving body comes from its increased energy. In short, energy fuas mass! By a few computerely simple mathemat. ical sterrs, Linsecis found the salue of the equiralent 1735 m in any unit of energy E and crpressed it by the equation [le). Geen this relation a high school freshman can take the remaining algebraic stere necessary state the most important and certoinly the most famous squrtain in history: Ex-me* The part pured by this eyjunnion in the developtricts of the stunne bxumb familiar to most nens. gyver readless li states in the shorthand of physics that the main conimed in any particle of matter 3 cqual to the mass of the body (in gras) multi-

·No text on this page.

·THE UNIVERSE AND DR. EINSTEIN of surut are resolved The bafiling interplay of marter and radiation which appears sometimes to be 1 concourse of particles and sometimes a meeting of wares, becomes more understandable. The dual role of the electron is a unit of matter and a unit of electricicy, the wpyc clection, the photon, waves of marter, wares of probability, a unirerse of wares all these scom less paradoxical. For all these concepts simply describe different manifestations of the same underiying reality, and it no longer makes sense to 3sk skat any one of them "really” is. Alatier and chengy' arc interchangeable. If marter sheds its mass and travels with the specd of lighe we call it mdiztion or energy And converscly if cnergy congeals and becomes inert and we can ascertain its inass wc call it mitter. I crecoforc science could only nore their ephemeral properties and relations as they Kuched the perceptions of earthlmund man. But since July 16, 1945 mja has been able to transform me into rlic orlicr. For on that night at Alamoporan, Neus Mexico, man for the first time transirutců a substantial quantity of matter into the light, huat, sound, and motion uhich we call energy, Yor the fundamental mystert ret1!3ms. The whole mitch of science toward the unification of concepts -the reduction of all me to clements and then to a les espaces para eles, the reduction of "eces" to the mgle concept "energy," and then the reduc. 1767 of mutter und energy to a single basic quantity ·space and THE UNIVERSE AND DR. EINSTEIN leads still to the unknown. The man merge into one, to which there may never be answer: what is the essence of this mass-energy stance, what is the underlying stratum of :'; reality which science seeks to explore? Thus Relativity, like the Quantum. T... draws man's intellcct still farther away from the Newtonian universe, firmly rooted time and functioning like some great, unerring, and manageable machine. Einstein's laws of motion, his basic principles of the relativity of distance, time, and mass, and his deductions from these principle comprise what is known as the Special Theory of Relativity. In the decade following the publication of this original work, he expanded his scientific and philosophical system into the General Theory of : Relativity, through which he examined the myste. rious force that guides the whirling of the stars, .; comers, mercors, and galaxies, and all the moving systems of iron, stone, vapor, and fame in the im. mense inscrutable void Newton called this force "universal gravitation." From lus own concept of gravitation Einstein attained a view of the vast architecture and anatomy of the unnerse as a whole.

·No text on this page.

·1
THE UNIVERSE AND DR, EINSTEIN
leads still to the unknown. The many questio
merge into one, to which there may never de
answer: what is the essence of this mass-energy su
stance, what is the underlying stratum of physi
reality which science seeks to explore?
Thus Relativity, like the Quantum Theory
draws man's intellect scill farther away from the
Newtonian universe, firmly rooted in space
and
rime and functioning like some great, unerring, and
manageable machine. Einstein's laws of motion, his
basic principles of the relativity of distance, cime
and mass, and his deductions from these principles
comprise what is known as the Special Theory of
Relativity. In the decade following the publication
of this original work, he expanded his scientific and
philosophical system into the General Theory of
Relativity, through which he esamined the myste
rious force that guides the whirling of the starse
comers, meteors, and galaxies, and all the moving
systerns of iron, stone, vapor, and Aame in the inte
mense inscrutable void Newton called this force
"universal gravitation." From his own concept of
gravitation Enstein attained a view of the researchi,
tecture ind anaromy of the universe as a whole.

·크

·No text on this page.

·Lick Ob.enators, Crossley Reflector The great Andromeda galax) is a giant slar system similar in shape and structure to our own Milky Was Although it can be seen with The naked eye as a funt luminescence in the constellation Andromalati on tight scan away yet it is the nearest of all the and unseres that wheel in the depths of space. Its diameter is AXINXI Night years to an observer situated in this galary, our MUL> W.) would look very much like this The smaller nebulostins near hy he manor members of the super-gulasix cluster that encompass the Andromeda spital oue Milky Way, and the Magellank Clouds

·No text on this page.

·"The nanmathematician," says Albert Einstein, Mis seized by a mysterious shuddering when he licars of 'four-dimensional' things, by a feeling not unlike that awakened by thoughts of the occult. And yet there is no more commonplace statement than that the world in which we live is a fourdimensional space-time continuum." A nonmathematician might question Einstein's use of the cerin "commonplace in this connection, Yet the difficulty lies more in the wording than the ideas. Once the meaning of the word "continuum" is properly grasped Einstein's picture of the uniscrse as a four-dimensional space-time continuumand this is the view that underlies all modern conceptions of the universe--becomes perfectly clear. A continuum is someching that is continuous. A ruler, for clample, is a one-dimensional space continuum. Most rulers are divided into inches and fraccions sealed down to one-sixteenth of an inch. But it is possible to imagine a ruler calibrated to 1 millionth or a billionth of an inch. In theory there is no reason why the steps froin point to point should not be even smaller. The distinguishing characteristic of a continuum is that the interval separatng any two points may lie divided into an infinite mules of arbitrarily small steps A railrord rack us a one-dimensional space con

·No text on this page.

·THE UNTES DR, EN 12 mo-dicension dollar me was the fight of an aptein Vorters o Los Angeles can best be picrundsatoren ronal spacc-time condition. The fact ATE OLD 14w ancora LOW Dezt 100 ETYRI 1270w ON ANY w KETUA WES to 20 p) 1993 tontt* The nesiboudd run of a New Yo: Chiap TELI tored in a two-directional space content Planc is 20 Jatitude 3, Inaginede), mentre rreurs poching to the trasco de Time unless the time co-ordinate 's also comes the fourth dimentsioa Arditore terrorist he Right a whole, as a charici siya ankst. ve broken dous into a series contes offs, climbs, glides and landemerker thought of as a conii.cos conforte Siemal spacc-time cmimi Since time is an inprimable at they sible to draw a picture of GC 15 .

·* THE UNIVERSE AND DR. EINSTEIN be imagined and it can be represented mathematica ly. And in order to describe the stupendous reach of the universe beyond our solar system, beyond th clusters and star clouds of the Milky Way, beyon the lonely outer galaxies burning in the void, th scientist must visualize it all is a continuun in thre dimensions of space and one of cimic. In our mind we tend to separate these dimensions; we have : awareness of space and an awareness of time. Bu the separation is purely subjective, and as the Spe cial Theory of Relativity showed, space and tim separately are relative quantities which vary wil individual observers. In any objective description o the universe, such as science demands, the time di mension can no more be detached from the spac dimension than length can be detached from breadt! and thickness in an accurate representation of house, 3 tree, or Betty Grablc. According to the grear German mathematician, Herman Alinkonski who developed the mathematics of the space-tim continuum as a convenient medium for expressing the principles of Relativity,"space and time scparacely have vanished into the mcrcst shadows and only a sort of combination of the two prescries any seality." It must not be thoughe, however, that the spacetime continuum is simply a mathematical construction. The world is a spacc-time continuum; all scality exists both in space and in time, and the two are indivisible. Al measurements of time are really ITCosurements in space, and conversely measurements in space depend on measurements of tinic. 76 ·sun, THE UNIVERSE AND DR. EINSTEIN Seconds, minutes, hours, days, weeks, months, scasons, years, are measurements of the earth's position in space relative to the sun, moon, and stars. Simiatly lacitude and longitude, the terms whereby man defines his spatial position on earth, are measured in minutes and seconds, and to compute them accurately one must know the time of day and the Jay of the year. Such "landmarks" as the Equator, the Tropic of Cancer, or the Arctic Circle are simply sundials which clock the changing seasons; and Prime Meridian is a co-ordinate of daily time; and "moon" is nothing more than an angle of the Even so, the cquivalence of space and time becomes really clear only when one contemplates the stars. Among the familiar constellations, some are "real" in that their component stars comprisc true. gravitational systems, moving in an orderly fashion relative to one another; others are only apparent their patterns are accidents of perspective, created by a scaining adjacency of uarelated stars along the linc of sight. Within such optical constellations one may obscric two stars of equal brightness and assert that they are "side by side" in the firmament, whereas in actualszy one may be 40 light years and the orher 400 light years away. Obviously the astronomer has to'chunk of the uni. croc as 3 Space-time continuum. When he pects through his telescope hc looks not only outward in space but backward in time. His sensitive cameras can detect the glommer of island universes 500 milhon light years ay ay-saint glcams that began their 7

·No text on this page.

·10 In the Special Theory of Relativity, Einstein stud. ied the phenomenon of motion and showed that there appears to be no fixed standard in the universe by which man can judge the "absoluce" motion of the earth or of any other moving system. Motion can be detected only as a change of position with respect to another body. We know for example that the carth is moving around the sun at the rate of twenty miles a second. The changing seasons suggest this fact. But until four hundred years ago men though the shifting position of the sun in the sky resealed the sun's movement around the earth; and on this assumption ancient astronomers developed a perfectly practical system of cclestsal mechanics which enabled them to predict with great accuracy all the major phenomena of the heavens. Their sup. position was a natural one, for we can't feel our motion through space; nor has any physical experimeno crer prored thac the earth actually is in motion. And though all the other piances, stars, galaxies, and moving systems in the universe are ceaselessly, restlessly changing position, their movements are Olsen ablc only with respect to one another. If all the objects in the universe were semoved save one, then na one could say whether that one remaining mbject uw at rest ar hurthng through the void at 79 ·THE UNIVERSE AND DR. EINSTEIN journey at a period of terrestrial time when the first vertebrates were starting to crawl from warm Paleozoic seas onto the young continents of Earth. His spectroscope tells him, moreover, that these huge outer systems are hurting into limbo, away from our own galaxy, at incredible velocities ranging up to 35,000 miles a second. Or, more precisely, they zrcte receding from us 500 million years ago. Where they are "now," or whether they even exist "nou," no one can say. If we break down our picture of the universe into three subjective dimensions of spact and one of local time, then these galaxies have no objective existence save as faint smudges of ancient enfeebled light on a phorographic plate. They at. rain physical reality only in their proper frame of reference, which is the four-dimensional space-time continuum. In man's brief tenancy on earth hc egocentrically orders events in his mind according to his own feelings of past, present, and future. But crccpt on the recls of one's own conciousness, the universe, the objective world of reality, does nor "happen"-it simply crists. It can be encompassed in its cntire majesty only by 3 cosmic intellect. But it can also bc sepresented symbolcally, by a mathematician, as a four-dimensional space-time continuum. AB understanding of the space-time continuum is requisite to a comprehension of the General Thicory of Rclativity and of what it says about gausitation, edic unscen force that liolds the universe together and determines its slape and size.

·THE UNIYERSE AND DR. EINSTEIN In the Special Theory of Relativity he had taken as his promise the simple assertion that the laws of nacure are the same for all systems moving imiformly relatise to one another. And as a steadfast believer in the universal harmony of nature he refused to believe that any system in a state of nonuniform motion must be a uniquely distinguished system in which the laws of nature are different. Hence as the basic premise of his General Theory of Relativity, he stated: the laws of nature are the same for all systeins regardless of their state of motion. In de- Icloping this thesis he worked out new laws of gravitation which upset most of the concepts that had shaped man's picture of the universe for three hundred years. Linstein's springboard was Newton's Law of Inertia which, as every schoolboy knows, states that "every body continues in its state of rest, or of uniform motion in a strught line, unless it is compelled to change that state by forces impressed thercon." It is incrua, therefore, which produces our peculiar sensations when a railroad train suddenly slow's doun or speeds up or rounds a curve. Our body 1 ants to continue moving uniformly in a straight linc, and when the train impresses an opposing force upon us the propery called incrtia tends to Issist the force. It is also inertia uhuch causes a locomincios hecze and strain in order to accelerate 3 long tram of freight cars. But this leads to another consideration. If the cits arc fodled the locomotie has to work harder ·THE UNIVERSE AND DR. EINSTEIN 100,000 miles a second. Alotion is a rclatire state; unless there is some system of reference to which is may be compared, it is meaningless to speak of the motion of a singic body. Shortly after publishing the Special Theory of Relativity, however, Einstein began wondering if there is not indeed one kind of motion which may be considered "absolute" in that it can be detected by the physical effect it cxerts on the moving system itself without reference to any other system. For example, an observer in a smoothly running erain is unable to tell by experiments performed inside the train wliether he is in mocion or at rest. But if the engincer of the train suddenly applics the brakes or jerks open the throttle, he will then be made awarc.. by the resulting zolt, of a change in his velocity. And if the train rounds a curn, he will know hy rhcoulward tug of his own body, resisting a change of direccion, char the crain's course has been alcored in a certain way. Therefore, Einstein reasoned, if only one objcct existed in the cntire universamehe earth for cramplomand it suddenly began to gyrate ir scgularly, its inhabitants would be uncomfortably aware of their motion. This suggests that nouuniform motion, such as that produced by forces and accelerations, may be "absolute" after all. It also suggests that cmpty space can serve as a system of rcfcrcncc within which it is possible to distinguish absolate motion. To Einstein, who held that space is nothing and motion is relative, the apparently unique character of nonuniform motion was profoundly disturbing. 80 ·THE UNIVERSE AND DR. EINSTEIN cgoal force, move at telocities that are strictly derecmined by their massa li would appear as though the factor of inertia operates only in a horizontal plaac. Newton's solution of this riddle is given in his Law of Gravitation, which states simply that the mystcrious force by which a material body attracts another body increases with the mass of the object is attracts. The bigger the object, the suonger the call of gravity. If an object is small, its inertis or rendency to resist motion is small, but the force that gravity creres upon it is also small. If an object is big, its inertia is great, but the force chat gravity excres upon it is also great. Hence gravity is always excrted in the precise degree necessary to overcome the inertia of any object. And that is why all objects fall at the same sare, regardless of their inertial mass This rather remarkable coincidence the perfect balance of gravation and inertia accepted un faith, but never understood or explained, for three centuries after Newton Alt of modern mechanics and engineering STCW out of Newtonian concepts, and inc heaucns appeared to operate in accordance sith hfawr Einstein, however, whose discoveries have all sprung from an inlicrent distruse of dog- 171.1, dishked seseral of Neuron's assumptions. He Anubited that the balance of gravitation and inertia wax merely an accident of nature. And he rejected the idea of gravitation being a force that can be created instantaneously over great distances. The Bonon that the carth can reach our into space and 82 ·THE UNIVERSE AND DR. EINSTEIN and burn more coal than if she cars are empty. To his Law of Inertia Newton thereforc added a second] law stating that the amount of force necessary to accelerate a body depends on the mass of the body; and that if the same force is applied to two bodies of different masses, then it will produce a greater ac. celeration in the smaller body than in the bigger one. This principle holds true for the whole range of man's everyday experience from pushing a baby carriage to firing a cannon. It simply generalizes the obvious fact that onc can throw a bascball farther and faster than one can throw a cannonball. There is, however, one peculiar situation in which there appears to be no connection between the ac, ccleration of a moving body and its mass. The biseball and the cannonball attain exactly the same mare of acceleration when they are fallmg. This phenomenon was first discovered by Galileo, who proved by experiment thr, discounting air resistance, bodies all fall at precisely the same rate regardless of their size or composition. A bascball and a landkerchief fall at different speeds only because the handkerchief offers 3 larger surface to the resistance of the air. But objects of comparable shape, such as a marble, 1 baseball, and a cannonball, fall at the same rate. (In a vacuum the landkerchief and the cannonball would fall side by side.) This phenome. non appears to violac Newton's Lair of incrriz. For why should all objects travel vertically at the same velocity regardless of their size or mass, if thiosc same objects, when projected horizontally by an 82 ·in accordance with his usual mode of creative. thought Einstein set the stage with an imaginary situation. The details have doubtless been envisaged by many another dreamer in restless slumber or in moments of insomniac fancy. He pictured an immensely high building and inside it an elevator that has slipped from its cables and is falling freely. Within thc clevator a group of physicists, undisturbed by any suspicion that their ride may end in disaster, are performing experiments. take objects from their pockets, a fountain pen, a coin, a bunch of keys, and release them from their grasp. Noching happens. The pen, the coin, the keys appear to the men in the elevator to remain poised in mid-air--because all of them are falling, along wich thic clevator and the men, at precisely the same rate in accordance with Newton's Law of Gravitation Since the men in the clerator are unaware of their prcelicament, however, they may explain thesc pe.. culiar happenings by a different assumption. They may bclicte they live heen magically transportes outside the gravitational field of the carth and arc in fars poised somculierc in empty space. And the harc gond grounds for such a belief. If one of their jumps from the floor le Noats sinmohly toward the coiling with a velocity just proportional to the rigys B5

·THE UNIVERSE AND DR. EINSTEIN
pull an object toward it with a force miraculously
and invariably equal to the inertial resistance of that
object seemed to Einstein highly improbable. So
out of his objections hc erolved 3 new theory of
graviration which, cxperience has shown, gives a
more accurate picture of nature than Newton's
classic law.

·in accordance with his usual modo of creativo thought Einstein see the stage with an imaginary situation. The details have doubtless been envisaged by many another dreamer in restless slumber of in moments of insomniac fancy, He pictured an immensely high building and inside it an elevator that has slipped from its cables and is falling freely. Within the clevator a group of physicists, undisturbed by any suspicion that their ride may end in disaster, are performing experiments. They cake objects from their pockers, a fountain pen, a coin, a bunch of keys, and release them from their grasp Nothing happens. The pen, the coin, the keys appear to the men in the clcvacor to remain poised in mid-air-bccausc all of them are falling, along with the elevator and the men, ac precisely the same rate in accordance with Newton's Law of Gravitation. Since the men in the elevator are unaware of their predicaniens, however, they may explain these peculiar happenings by a different assumption. They miay believe they he licen magically transported ourside the gravicarional field of the carth and are in fact poised somewhere in empty space. And they fuave good grounds for such a belief. If one of them junspy from the floor he floats smoothly toward the ceiling with a velocity just proportional to the vigo: 8

·UNIVERSE ANU DR. EINSTEIN
pull an object toward it with a force miraculously
and invariably equal to the inertial resistance of that
object seemed to Einstein highly improbable. So
out of his objections he evolved a new theory of
gravitation which, crperience has shown, gives a
more accurate picture of nature than Neuton's
classic law.

·THE UNIVERSE AND DR. EINSTEIN' There is really no way for them to tell whether they arc at rest in a gravitational field or ascending with constant acceleration through outer space where there is no gravity at all. The same dilemma would confront them if their room were attached to the rim of a huge rotating merry-go-round ser in outer space. They would feel a stranige force trying to pull them away from the center of the merry-go-round, and a sophisticated ourside observer would quickly identify this force is incrtia (or, as it is termed in the case of rotating objects, ' centrifugal force). But the men inside the room, who as usual arc unaware of their odd predicament, would once again attribute the force to gravity, For of the interior of their room is empty and unadorned, there will be nothing to tell therr which is the floor and which is the ceiling except the force that pulls them toward one of its interior surfaces. So what a detached observer would call tho "outside wall" of the rotating room becomes thc "oor" of the room for the men inside. A moment's rcilection shows that there is no "up" or "down" in empty space What we on earth call "down" is simply the direction of gravity. To a man on the sun it would appear that the Australians, Africans, and Argentinos arc hanging by their heels from the southern liemisphere. By the same token Admiral Byrd's flight over the South Pole was a geometrical fiction, actually he few under it-upside down. And so the men inside the room on the merry-goround will find that all elicit cxperiments producı exactly the same results as the one they performe 8

·No text on this page.

·posedly screal the state of motion of a body, even if Il exists alonc in space, are indistinguishable from the effects of gravitation. Thus in the case of the merry-go-round, what one observer identified as the pull of incrtia or centnfugal force and therefore an effect of motion, another observer identified as the familiar tug of gravitation. And any other inercial cficct produced by a change of specd or a change of direction can equally well be ascribed to a changing or fluctuating gravitational ficld. So the basic promise of Relativity holds true; motion, both uniform and nonuniform, can only be judged with sespect to some system of reference absolute motion does not exist. The sword with which Einstein slew the dragon of alsolute motion was gravitation. But what is gravitation. The gravitation of Einstein is somc. thing entirely different from the gravitation of Newton. It is not a "force." The idea that bodies of matter can "attract" one another is, according to Einstein, an illusion that has grown out of erroncows mechanical concepts of nature. So long as one belicves that the universe is a big machine, it is natura to think that is vannak parts can exece a force on one another. Bur the deeper science probes towar scalıry, the more clearly it appears that the univers is not like machine at all. So Einstein's Law or Gravitation contains nothing aboue force. It dcscribes the bchavior of objects in a gravitational field --the plancts, fut clampic--not in terms of "attraclinn" but simply in terms of the pathis they follow. To Linstein, grátication is simply part of inertia; the 89 ·THE UNIVERSE AND DR. EINSTEIN when their room was being swept "upward" through space. Their feet stay firmly on the "floor." Solid objects "fall.” And once again they attribute these phenomena to the force of gravity and k. Jicvc themselves at rest in 3 gravitational field. From these fanciful occurrences Einstcin drew a conclusion of great theoretical importance. To physicists it is known as the Principle of Equivalence of Gravitation and Inertia. It simply states that rherc is no way to distinguish thc morion pinduced by inertial forces (acceleration, recoil, cen. trifugal force, erc.) from motion produced by grikitational force. The validity of this principle will be evident to any aviator; for in an airplane it is im. possible to separate the effects of inertia from those of gravitation. The physical sensation of pulling out of a dive is exactly chic same as that produced by cxccuring a srecply banked rurn at high spxod. In both cases the factor known to flyers as a "G-lord" (Gravity load) appears, blood is drawn away from the head, and the body is pulled hcavily dow's snto the sear. To the pilot who is flying "blind" and without instruments, the identical nature of these cffccts can prore a serious and cren faral matter, In this principle, which is the keystone of General Relativity, Einstein found in answer buch so the riddle of gravitation and the problem of "absolure" motion. It showed that there »s nothing unique or "absolutch about nononiform motion after all, for the cffects of nonuniform motion which can sup. 88 ·THE UNIVERSE AND DR. EINSTEIN by the field equations of Albert Einsceini. Just as Marwell and Faraday assumed that a mag- ACE CIEBIOS certain properties in stirrounding space. $0 Einstein concluded that stars, moons, and other celestial objects individually determine the propera ties of the space around them. And just as the movement of a piece of iron in a magnetic field is guided by the structure of the field, so the path of any body The field of a bar magnet 181 a gravitational field is determined by the goiry ní thar field The distinction between Newton's and instein's ideas about gravitation has sometimes foon illustratoil by picturing a little bay playing marblos in a city loc. The ground us very uneren, ridged as ich bumps and hollows. An observer in an office ton stories above the sucer would not be able 10 sec thiese irregularitics in the ground. Noticing thin the marbles appear to avoid some sections of 93 ·THE UNIVERSE AND DR. EINSTEIN movements of the starts and the planets stem from their inherent inertia; and the courses they follow are determined by the metric properties of space or more properly speaking, the metric properties of the space-time continuum. Although this sounds very abstract anderen paradoxical, a becomes quite clear as soon as one dismisses the notion thac bodies of matter can exert 2 physical force on each other across millions of miles of empty space. This concept of "action-at-a-distance" has troubled scicntists since Newton's day. It led to particular difficulty, for example, in understanding electric and magnetic phenomena. Today scientists no longer say that a magnet "artracts" a piece of iron by some kind of mysterious buc instantaneous acrion-ar-a-distance. They say rather that the magner creates a certain physical condition in the space around it, which they term 3 muaga netic field, and that this magnetic field then acts upon the iron and makes it bchave in certain predicrablc fashion. Students in any elementary science course know u hat a magnetic field looks like, because it can be rendered vrsible lạy the smple process of shaking iron filings onto a piece of stuff paper held above a magnice. A magrecic field and an clectric ficld are physical realities. They have a definite structurc, and their structure is described by the field equations of James Clerk Jarwch włuch pointed the way toward all the discos crics in clectrical and radio cnginering of the past century. gravitational field is as much of a physical rclity ar an electromagnetic field, and its structure is defined . OA

·1
THE UNIVERSE AND DR. EINSTEIN
ll'hen applicd to astronomical problems Linstein's
gravitational laus yield results that are close to those
given by Newton. If the results paralleled each
other in every case, scientists might tend to retain
the familist concepts of Newtonian law and write
off Einstein's theory as a weird if original fancy.
SUN
The 7oration of Mercury's elliptical orbit, greatly
exsecrared Actually the ellipse advances only
#3 seconds of an arc per century.
But a number of strange new plienomena have been
discovered, and at least onc old puizle solved, solely
in the basis of Gencral Relativity. The old puzzle
stemased from the eccentric behavior of the planer
Sfercury. Instead of revolving in its elliptical orbit
sith the regularity of the other planets, Micrcury
dorintes from its course cach jest by a slight but
93

·THE UNIVERSE AND OR. EINSTEIN the ground and move toward other sections, he might assume that a "force” was operating u hich can pelled the marbles from certain spors and attracted them toward others. But another observer on the ground would instantly perccive that the path of the marbles was simply governed by the currature of the field. In this little fable Newton is the upstairs observer who imagines that a "force" is at work, and Einstein is the observer on the ground, who has no reason to make such an assumption. Einstein's gravin tational laws, therefore, werely describe the field propertics of the space-time concinuum. Specifically, one group of these liters sets foreli ile selation becween the niass of a gravitating body and the structure of the field around it; they are called structure laws. A second group analyzes the paths descrilicd by moving bodies in gravitational fields; they are the laws of morion. It should not be thought that Einstein's thicory of 'graynation is only a fornal mathematical scheme. For it rests on assumptions of deep cosmic significancc. And the most semarkable of these assumpa cions is that the unsterse is not a rigid and JINUTIUEable cdifice wherc independent matter is housed in independent spacc and ac, it is on the contrary an amorphous continutus, withour any fixed architecture, plastic and variable, constantly subject change and dissortion 15hcreyes there is suitss and motion, the continuum is disturbed. Just 15 a fish swinming in the sea agitares the water around it, $0 a star, a conict, or a galary discorts the concery of the space-time through which it moves.

·12 The sequence of thought which led Einstein to prophesy this effect began with another imaginary situation. As before, the scene opens in an clevator ascending with constant acceleration through empty space, far from any gravitational field. This time sumc roving interstellar gunman impulsively fires a bullet at the clevator. The bullet hits the side of the car, passes clean through and emerges from the far wall at a point a little below the point at which it xenetrated the first wall. The reason for this is evidonc to the marksman on the outside. He knows that the buller ficw in a straight line, obcying Newton's Lax of Incrtul, but while it traversed the distance Peru.cen the two walls of the car, the whole eleva for traveled “upu ard ' a certain distance, causing tha second bullet hole to appear not opposite the first tunc lux slightly seares the fons llowever, the ob seriers inside the clesator, having no idea where in the universe they are, interprer the situation diffckently wate this in carth any musile describes parallic curve touard the ground, they simply conclude thu shey are at rest in a gravitational field and thar the ballct which passed through their cus **s alexribing a perfectly normal curve with se- Byxat to the time A 23Cn later 35 the car continues upyard -- ·THE UNIVERSE AND DR. EINSTEIN cxasperating degree. Astronomiers explored cvery possible factor that might cause this perturbarior Lot found no solution within the framework of Newtonian theory. It was not until Einstcin evolved his laws of gravitation that the problem was solved. Of all the planets Alercury lies closest to the sun. It is small and travels with great specd. Under Newtonian law thesc factors should not in themselves account for the deviation; the dynamics of Mercury's movement should be basically the same as those of any other planer. But under Einstcin's law's, the intensity of the sun's gravitational ficld and Nlcrcury's cnormous spced make a difference, causing the whole ellipse of Mercury's orbit to cxecute. slow but inexorable swing around the sun as the rate of one revolution in 3,000,000 years. This calo culation is in perfect agreement wuh actual measurements of the planet's course. Einstcin's mathe matics are dus more accurate than Nonton's in lcaling with high velocities and strong grarnational clas. An achievement of fas greater importance, how "es, than this solution of an old problem was Einin's prediction of a new cosmic plicnomenon of rich no scientist had ever drcamed-famcly the oct of gravitation on lighr.

·12 The sequence of thought which led Einstein to prophesy this effect began with another imaginary situation. As before, the scene opens in an derator ascending with constant acceleration through empty space, far from any gravitational field. This time some roving interstellar gunman impulsively fires a bullet at the elevator. The bullet hits the side of the as, passes clean through and emerges from the far wall at a pinnt a little below the point at which it penetrated the first wall. The reason for this is evident to the marksman on the outside. He knows that the bullcr flew in a straight line, obeying Newton's Law of Inesia, but while it traversed the distance beruccn the two walls of the car, the whole elevator traveled "upu ard" a certain discance, causing the second buller hule to appear not opposite the first onc lut slightly scator the floor. However, the obscriers inside the clevator, having no idea where in the universe they are, interpret the situation difiercoily lware that on canh any missile describes a parabolic cunc toward the ground, they simply Cinclude that shev ate at rest in a gravitational field and thus the bullet which passed through their ca *** describing a perccely normal curve with rejxt le the flexir A ven latct as the car continues upward 95 ·THE UNIVERSE AND DR. EINSTEIN exasperating degree. Astronomers cxplored crory possible factor that might cause this perturbation but found no solution within the framework of Newtonian thcory. It was not until Einstcin evolved his laws of gravitation that the problem w3s solved. Of all the planets Nfercury lies closest to the sun. le is small and travels with great speed. Under Now tonian law thesc factors should not in themselves account for the deviation; the dynamics of Mcrcury's movement should be basically the same as those of any other planet. But under Einstein's law, the intensity of the sun's gravitational ficld and Micrcury's enormous speed make a difference, causing the whole ellipse of Mercury's orbit to crecure a slow but inexorable swing around the sun at the rare of onc revolution in 3,000,000 years. This cal. culation is in perfect agreement with actual measurements of the planet's course. Einstein's mathc; matics are thus more accurate than Newton's in dealing with high velocitics and strong gravitational ficids. An achicvement of far grcater importance, how crer, than this solurion of an old problem was Einstein's prediction of a new cosinic phenomenon of which no scientist had crer drcamed-amely the cffect of gravitation on light.

·12 The sequence of thought which led Einstein to prophesy this effect began with another imaginary situation. As before, the scene opens in an devaror Ascending with constant acceleration through empty space, far from any gravitacional field. This time some roving interstellar gunman impulsively fires a ballet at the elevator. The bullet hits the side of the par, passes clean through and emerges from the far wall at a point a little below the point at which it penetrated the first wall. The reason for this is evident to the marksman on the outside. He knows that she bullc few in a straight line, obeying Newton's Law of Inertia, but while 1 traversed the distance between the two walls of the car, the whole elevafor traveled upward" a certain distance, causing the socand bullec hole to appear not opposite the first one ixt slightly ncarer the foor. However, the ob- Scncrs inside the clesacor, having no idca where in the universe they are, interpret the situation difierently Jware that on earth any missile describes a parabolic cunc touard the ground, chey simply cunclude that they are at rest in a gravitational field and that the bullet which passed through their car was descriling a perfectly normal curve with respect in the floor. A moment later as the car continues upward ·THE UNIVERSE AND DR. EINSTEIN through space a beam of lighe is suddenly Nashed through an aperture in the side of the car. Since the vclocity of light is great the beam traverses the distance between irs point of cntrance and the opposire. wall in a very small fraction of a sccond. Nevertheless the cur travels upward a certain distance in that interval, so the beam strikes the far wall a tiny fraca sion of an inch below the point at which it entered. If the observers within the car arc equipped with sufficiently delicate instruments of measurement they will be able to compute the curvature of the bcam. But the question is, hou will they explain it? They are still unaware of the motion of their car and believe themselves at rest in a gravitational field. If they cling to Nestonian principles they will be completely baffled because they will insist thac light ray's always travel in 1 straight line. But if they are familiar with the Special Theory of Relacivity they will remember that cnergy has mass in accordance with the equation m* E/c. Since light is a form of energy they will deduce that fight has nass and will therefore be affected by a gravitational field. Hence the curvature of the bcani. From these purely theoretical considerations Einstcin concluded that light, like any marcrial object, trareis in a curve which passing through the gravitational field of a missisc body. Ile suggested that liis theory could be put in test by observing the path of starlight in the gravitational field of the sun. Smco the stars are invisible by day, there is only onc 0001- sion when sun and stars can be seen together in the sky, and thar is during an eclipse. Einstcin proposed.

·THE UNIVERSE AND DR. EINSTEIN therefore, that photographs be taken of the stars immediately bordering the darkened face of the sun during an eclipse and compared with photographs of those same stars made at another time. Accord-. 3 STAR IMAGE! sub. EARTH The deflection of starlight in the gravitational field of the sun Since the light from a star in the peighborhood of the sun's disk bent inward, toward the sun, as is passes through the sun's gravitational field, the image of the star appears to observers on earth to be shifted outs and and away from the sun ing to his thenry the light from the stars surrounding the sun should be bent inward, coward the sun, in traseesing the sun's gravitational field; hence the images of those stars should appear to observers on carth to be slufted outward from their usual positions in the sky, Einstein calculated the degree of deflection that should be of crved and predicted that for the stars closest to the sun the deviation would be about 1.75 seconds of an arc. Since he seaked his whole Gencral Theory of Relativity on 97 ·THE UNIVERSE AND DR. EINSTEIN this test, men of science throughout the world anit: iously awaited the findings of expeditions which journeyed to equarorial regions to phorograph she eclipse of Vlay 29, 1919. When their pictures ulcrc developed and cxamined, the deflection of the starfighe in the gravitational field of the sun was found to average 1.6+ seconds figure as close to perfect agreement with Einstein's prediction as the amous racy of instruments allowed. Another prediction made by Einstein on the basis of General Relativity pertained to time. Having shown how the properties of space are affected bir a gravitacional field, Einstein scached the conclusion boyu analogous but somcu hat more involved rezan ing that tune intervals also vary with the gravitational field. A clock transported to the sun shwul! run at a slightly slower rhythin than on carti ini a radianng solar arom should emit light of Sightly lower frequency than an atom of the same clouent on earth. The difference in wave length would in This casc lc imnicasurably small But there are in the universe gravitational ficlds stronger than the sun's Onc of these surrounds the freak star known as the "companion of Sirius"- "-2 33 fuse dss arf compued of matter in a starc of such fantastic demiry that one cubic inch of it would weigh a ton on carth. Because of its great mass this corsordinary duurt, which is only three times larger than the carth, las a gravitatu tional field potent enough to perturb the movements of Sirius, screnty times its sirc. In field is also X11CT- 98 ·THE UNIVERSE AND OR. EINSTEIN ful enougk to slow down the frequency of its own radiation by a mcasurablc degrec, and spectroscopic oliservations have indeed proved that the frequency of light emitted by Sirius companion is reduced by the cract amount predicted by Einstein. The stift of wave length in the spectrum of this star is known to astronomers as "the Einstein Effecr" and constitutes an additional verification of General Relativiry.

·THE UNIVER55 AND DR. EINSTEIN this tesi, men of science throughout the world jously au arred the findings of expeditions whic journered wo equaronal regions to photograp) sh. eclipse of Vay 29. 1919 When their pictures per dei cloped and examined, tht defectuon of the sa: right in the Talstational field of the sun was foun to average ; font seconda figure as close to partec agreement with Estes prediction as the ante ract of instruments zowed Another pre RCTI, nadeln Linen on the basis of General Relativt pertani is some Hairs shoun hru phie pariperhiasan Dede vi attected by a graurearinmal nie's Linster" reachedincevacus }is analysies bur samen har mire gasoised re:50ding thar 13*1x unten als als are worth the Starttuwal ned 4 skach Transported on the sum siguld run at a slightly scorer shithin ihan om carh ind 2 radiaring var ainm should try handy sporty louer frequencs than 24 aromi fihe 12740 narrot on earth The differenes was longue this case hermeasurate in Mur+CE TO the univere grauitatuna' che rise than the cons. One of these curtains the fresh star mis 24 the "companion of Sinus -a s hie dus zones soned out matter in a start of such tantas c 36 37 y cine cubic inch of 11 Hruld wept a 17173 ron ( 29 Pot cauka of its great mass the entrane donar1 Jagro wich is only three times larger than the €200 hidastational field porrent cough to perturb he town 2014 of Sinus, ses enry rumes 175 se ir field is also cro 98 ·THE UNIVERSE AND DR. EINSTEIN ful enough to slow down the frequency of its own radiation by a measurable degree, and spectroscopic obserrations have indeed proved that the frequency *of light emitted by Sirius companion is reduced by the exact amount predicted by Einstein. The shift of wave length in the spectrum of this star is known O astronomers as "the Einstein Effect" and constiutes an additional verification of General Relativity.

·13 Up to this point the concepts of General Relarivity have dealt with the phenomena of the indi- . vidual gravitational field. Bur the universe is fille with incomputable bodies of mattermTeccon moons, comcts, ncbulae, and billions on billions o stars grouped by the interlocking geometry of thci gravitational fields in clusters, clouds, galaxies, and supergalactic systems. One naturally asks, whai chen is the over-all geometry of the space-time continuum in which they drift: In cruder fanguage, what is the shape and size of the universe All modern replies to the question have been derived directly or indirectly from the principles of General Relativity, Prior to Erstcin the universe was riost costimonly pictured as an island of matter afloat in the center of an infinite ses of space. There were several reasons for this concept. The universe, most scientists agreed, had to be infinite; because as soon as they" conceded chat space might come to an end some where, they were faced with the cmbarrassing question: "And what lies beyond that?" Yer Newtonian fax prohibited an infinire universe containing a uni. form distribution of manter, for then the total gravitational force of all the masses of matter stretching 3way to infinity would be infinite, and 100 ·space be sparser and THE UNIVERSE AND DR. EINSTEIN the heavens would be ablaze with infinite light. To man's feeble eye, moreover, it appeared that beyond the rim of our Alilky Way the lamps of Dame sparser, diffusing gradually in artenuared outposts like lonely lighthouses on the frontiers of the fathomless void. But the island uni- Ferse presenred difficulties too. The amount of matter it held was 50 small by contrast with an in- Inicy of space thac inevitably the dynamic laxt's governing the morements of the galaxies would Muse them to disperse like the droplers of a cloud and the universe would become entirely empty. To Einstein this picture of dissolution and disappearance scenied eminently unsatisfactory. The kasic difficulty, he decided, derived from man's natural but unwarranted assumprion that the geomctry of the universe must be the same as that revealed hy his senses ficre on earth. We confidently assume, fixe example, that two parallel beams of light will travel through space forever without meeting, bem cause in the infinite plane of Euclidean geometry parallel lines never mect. Ille also feel certain that in outer space, as on a tennis court, a straight line is clic shortest distance betu een two points. And yet Cuclid never actuilly proved that a straight line is the shortage distance betu'ccn two points; he simply arburanly defined a graight line as the shortest distance between two points. Is it nor then possible, Einstein asked, that man is being deceived by his luued perceptions wiren hc pictures the universe in the garb of Luclidean Boomerry) There was a time when man thought the ·THE UNIVERSE AND DR. EINSTEIN earth was fiat. Now he accepts the fact that the eart is round, and he knows that on the surface of the earth the shortest distance berween two such points as New York and London is not a straight compass course across the Atlantic but a "great circle" that veers northward past Nova Scotia, Newfoundland and Iceland. So far as the surface of the earth is conroca cerned Euclid's geometry is not valid. A giant rriangle, drawn on the carth's surface from two points on the Equator to the North Pole, would not satisfy Euclid's theorem that the sum of the interior angles of a triangle is always equal to two right angles or 180 degrees. It would contain more than 180 degrees, as a glance at the globe will quickly show. And if someone should draly a giant circle on the carth's surface he would find that the ratio berween its 102 ·THE UNIVERSE AND DR. EINSTEIN diameter and its circumference is less than the classic talue si. These departures from Luclid are due to the curvature of the earth. Although no one doubts today that the earth has a curvature, man did not discover this fact by getting off the earth and looking as it The curvature of the earth can be computed very comfortably on terra firma by a proper mathematical interpretation of casily observable faces in the same way, by a synthesis of astronomiml fact and deduction, Einstein concluded that the universe is neither infinite nor Euclideant, as most scientists supposed, but something kicherto unimagined It hasatready been shown thar Euclidean geometry does not hold true in a gravitational field. Light rays do not travel in straight lines when passing through a gravitacional field, for the geometry of the field is such that within it there are no straight lines, the shortest Course that the light can describe is a curve of great circie słuch is Ngorously determined by the geometrical structure of the field. Since the structure of a gravitational field is shaped by the mass and relocity of the gravitating body-stat, moon, or plancimit follows that the geometrical structure of the universe as a whole must be shaped by the sum of its marerial content. Fos esch concentration of matter in the universe there is a corresponding distoruon of the space-time continuum. Each telestial body, cach galaxy creates localitregy- 101 ·THE UNIVERSE AND DR. EINSTEIN larities in space-time, like cddics around islands in the sea. The greater the concentration of marter, the greater the resulting currature of space-time. And the total cffect is an over-all curvature of the whole space-time continuum. the combined distortions produced by all the incomputable masses of matter in the universe cause the continuum to bend back on itself in a great closed cosmic curve. The Einsccin universe therefore is non-Euclidean and finite. To earthbound man a light ray may ap.. pear to travel in a straight line to infinity, just us to an earthworm cr.wling "straight" ahead forever and ever the earth may seem both fat and infinite. But man's impression that the universe is Euclidean in character, like the earthworm's impression of the earth, is imparted by the limitations of his senses. In the Einstein universe there are no straight lines, there are only great circles. Space, though finite, is unbounded, a mathematician would describe its geometrical character as the four-dimensional anar loguc of the surface of a spherc. In the less abstract words of the larc British physicist, Sir James Jeans: "A soap-bubble with corrugations on its surface is perhaps the best representation, in terms of simple and familiar materials, of the new universe revealed to us by the Theory of Relativity. The universe is not the interior of the soap-bubble bur its surface, and we must always remember that while the surface of the soup-bubble fuas only two dimensions, the universe bubble has four-three dimensions of space and one of time. And the substance our of ·THE UNIVERSE AND DR, EINSTEIN which this bubble is blown, the soap-film, is empty space welded onto empty time." Like most of the concepts of modern science, Einstein's finite, spherical universe cannot be visualized many more than a photon or an electron can be sisualized. But as in the case of the photon and the electron irs properties can be described mathematically. By taking the best available values of modern astronomy and applying them to Einstein's 'field cquations, it is possible to compute the size of the universe. In order to determine its radius, however, it is first necessary to ascertain its curvature. Since, as Einstein showed, the geometry or curcature of space is determined by its material conrent, the cosmological problem can be solved only by abraining a figure for the average density of matter in the universe. Fortunately this figure is available, for astron- Omer Edwin Ilubblc of the Mr. Wilson Observatory conscientuusly studied sample areas of the hcavens over a period of years and parostakingly computed the average amount of matter contained in them. The conclusion he reached was that in thc universe 25 a whole there is 0000000000000000000- 00000000001 gram of montes per cuinc centimeter of space Applied to Linstein's ficld equations this figurc yields a positive value for the curvature of the universe, which in turn reveals that the radius of the universe is 35 lullson light years or 210,000,000,000,- 000,00.000,000 miles Einstein's universe, while not Infinisc, is neverheless sufficiently enormous to en-

·THE UNIVERSE AND DR. EINSTEIN
compass billions of galaxies, each containing hun
dreds of millions of flaming stars and incalculable
quantities of rarchied gas, cold systems of iron and
stone and cosmic dust. A sunbeam, setting out
through space at the rate of 186,000 miles a second
would, in this universe, describe a great cosmic
circle and return to its source after a little more than
200 billion terrestrial years.

·14 At the time Einstein evolved his cosmology, he was unaware, however, of a strange astronomical phenomenon which was only interpreted several years later. He had assumed that the motions of the stars and galaxies were random, like the aimless Vrifting of molecules in a gis. Since there was no cvidence of any unicy in their wanderings he had ignored them entely and regarded the universe as static Pur astronomers were beginning to notice signs of a syscematic movement among the outer galaxies at the extreme limits of relescopic vision. All these outlying galaxies, or "island universes," are, apparently, receding from our solar system and from each ocher. This organized fight of the distang galatic-the remotest of them being about 500 million light ycars ass ay-s an entirely different affair frans the indolent i hecling of the nearer grasicaunal systems. For such a systematic movement would have an effect on the curvature of the uni- Ierse as a whole. The universe is, therefore, not static; it is expandng in somewhat the same manner as a soap bubble « a balloon expands. The analogy is not quite exact.. however, for if we conceive of the universe as a kind of smuted balloon--the spots representing mistrerne would crpect the sports to expand too.

·THE UNIVERSE AND DR. EINSTEIN But this cannot be, because then tre tould never notice the expansion, just as Alice in Wonderland would have been unaware of the sudden changes in stature if all her surroundings had grown and contracted along with her. Therefore, as cosmologist H. P. Robertson of the California Institute of Technology has pointed out, in visualizing the universe as a sported balloon, we must think of the spots as inclastic patches sewn upon the surface, Marcial bodies retain their dimensions while space strerches out between them, like the skin of thic balloon be tween the patches. This exmordinary phenomenon greatly complicares cosmology. If the spectroscopic analysis that indicates the recession of these outer galaxies is correct (as most astronomers bcheve it to bc) then the relocities at which they are vanishing into linho are almost beyond bclcf. Their specd appears to in crease with distance. While the nearer galaxies, about one million light years away, are traveling at a mere 100 miles a second, those 250 million light y cars away arc flying off at the fantastic rate of 25,000 miles 3 second, almost one seventh the relocity of light. Since all of these remote galaxics, with our erception, are moving away from us and from cach other, one must conclude that at some cpoch of Cosmic time all of them were clustered together in one fiery inchoate maiss And if the geometry of space is shaped by its material content then the universe in this pregalactic pluse must have been 181 uncomfortably cramped and crowiled receptacle, characterized by an ercessivc curvature and pached 108 ·THE UNIVERSE AND DR. EINSTEIN with matter in a state of inconceivable density. Cal culations based on the velocities of the seceding galaxies show that they must have separated and started their fight from the "center" of this shrunkan universe about two billion years ago. Several theories have been advanced by astronor mers and cosmologists to explain the enigma of the expanding universe. One, put forth by the Belgiant cosmologist Abbé Lemaitre, proposes that the uniserse originated from a single stupendous primeval to which exploded and thus precipkated the ex* pansion which we still perceive. An analogous shtory, made public recently by Dr. Gcorge Cassss of George Washingtos Usssessísy, 1.5555* structs in detail how the constirucne elements might ktere been forged in the dense flasing core of the universe before it started to expand. In the beginning, says Dr. Games, the nucleus of the universe was an infernn of lomogencous primordial vapor seerinng at unimaginable temperatures such as no longer crist even in the interiors of stars. (The temperature of the sun. which is an arerage star, ranges from $500 Centigrade at the surface up, 49,000,000 in the interior) There were no cle- 1ents in such heat, no molecules, no atoms othing lut free ncutrams in a state of chaotic agiration. When the comic mass kicgan to cypand, how'cser, the temperature began to fall, and when it had dropped to atxour one billion degrees the ncutrons . (undensed into aegroraces, electrons 'Wtre etnited to ·THE UNIVERSE AND DR. EINSTEIN which attached themselves to nuclei, and atoms wera formcd. All the elements in the universe werc thu created within the space of a few critical moment in the cosmic dawn and their roles fixed for the two billion years of continuing expansion that ensued An earlier theory of the expanding universe, pus forth some years ago by Dr. R. C. Tolman of the California Institute of Technology, suggests th31 the cosmic expansion may be simply a temporary condition which will be followed at somc future cpoch of cosmic time by a period of contraction The universe in this picture is 3 pulsating balloon in which cycles of cxpansion and coneraction succeed cach other through eternity. These cycles are gox. crned by changes in the amount of master in the unkerse; for as Einstein showed, the curvature of the universe is dependent on its content. The difficulty with this theory is that it rests on the assuniprion that somewhere in the universe matter is being formed. Although it is true that the amount of matter in the universe is perpctually changing, the change appcars to be all in one direction toward dissolurion. All the phenomena of nature, visible and invisiblc, within the atom and in outer space. indicate that the substance and cnergy of the unia verse arc inexorably diffusing like rapor through the insatiable void. The sun is slowly but surely buming out, the stars are dying embers, and overywhere in the cosmos heat is tuming to cold, matter is dissolving into radiation, and energy is being dissipated into empty space. The universe is thus progressing toward an ulti- ·THE UNIVERSE AND DR. EINSTEIN ETIC "heat-death," or as it is technically defined, a condition of "marimum entropy." When the uni- Ferse reaches this state some billions of years from now all the processes of nature will cease. AJI space will be at the samc temperature. No energy can be used because all of it will be uniformly distributed through the cosmos. There will be no light, no life, no warmth nothing but perpetual and irrevocable stagnation. Time itself will come to an end. For entrapy points the direction of time Entropy is the measure of randomness When all system and order in the universe have vanished, when randomness is at its maximum, and entropy cannot be increased, when there no longer is any sequence of cause and cffect, in short when the universe has run down, there will be no direction to time-there will be no tine. And there is no way of avoiding this destiny. For thic fateful principle known as the Second Law of Thermodynames, which stands today is virtually the only pillar of classical physics left intact by the march of science, proclaims that lie fundanicacal processes of nature are irreversible. Nature mitoses just one way. There are a few contemporary theorists, howcier, who propose that somehow, someu here bem send man's mesger ken the universe may be rebulding itself in the light of Lunstein's principle of the cquivalence of mass and energy, it is possible to imagine the diffused radiation in space congealing once more into particles of matice-electrons, atunis, and molecules-such may then combine to forma larger units, « fuck in tim may be collected ·THE UNIVERSE AND DR. EINSTEIN by their own grarintional influence into diffuse nebulac, stars, and ultimately, galactic systems. And chus the life cycle of the universe may be repeated for all eternity. Laboratory experiments hare indeed demonstrated that photons of high-energy radiafion, such as garuma mys, an, under certain conditions, interact with matter to produce pairs of clectrons and positrons. Astronomers have also de termined recently thar aroms of the lighter clemenrs, drifting in spacehydrogen, helium, oxygen, nitrogen, and carbon-pay slowly coalesce into nolecules and microscopic particles of dust and gas. And still more recent Dr. Fred L. Whipple of Hanard has described in his "Dust Cloud Hypotlıcsis." pulsa lished in 1948, how the girched costic dust that floars in interstellar space in quanticics cgual in mass to all the visible mater in the universe could in the course of w billion years condense and coagulare inco stars. According to Whipple clicse tiny dust particles, barcly onc fifty-thousandel of an inch in diameter, are blown together by the delicate pres- Sure of starlighr, jusr as the fine-spun tail of a comet is dcffected away from the sun by the impact of solar photons. As the particles cohere, an aggregate is formed, then a cloudler, and then a cloud. Illen the cloud attains gigantic proportions (i..., when its diameter exceeds six trillion miles), its mass and density will be sufficient to set a new sequence of physical processes into operation Gravity will cause the cloud to contract, and its contraction will cause its internal pressure and temperature to risc. Eventually, in the last white-hot stages of its collapse, it 312 ·THE UNIVERSE AND DR, EINSTEIN will begin to radiate as a star. Theory shows that our solar system might have evolved, in special circumstances from such a process mour sun being the star in question and the various planets small cold" by-products condensed from sulsidiary cloudlets spiraling within the main cloud. Presupposing the possibility of such events as tliesc, one might arrive ultimately as the concept of a self-perperuating pulsating universe, renewing its Cycles of formation and dissolution, light and darkness, order and disorder, heat and cold, expansion and contraction, through never-ending cons of time. And y'et this picture las not been widely accepted kxcause no definite evidence has been found to support ic. Although duse clouds of all dinensions and degrees of density can be seen hanging in the abyss of interstellar space, no one can stare from man's lisicf temporal perspective clear they are proro-stars, any more than one can say with assurance that a white cumulus cloud riding the blue atmosphere of nur earth on any given day is tomorrow's thunder storm or simply an cvanescent wraith of mist thar sinds have gathered and will presently disperse. Tur apart from conjecture on the origins of our solar system of the individual stars or any component part of the system of nature in which we stand. there are theoreucal as well as empirical difficulties inherenr in every suggestion that the universe as a *hnic may still be abuilding. Nothing in all inaniface mature can be unmistakably identified as a pure creative process. At one time, for example, ir #3s thought that the mysterious cosmic rays which ·THE UNIVERSE AND DR. EINSTEIN continually bombard the carth from outer spac might be by-products of some process of atomi creation. But there is greater support for the oppo síte view that they are by-products of atomic annih lation. Everything indeed, everything risiblc is naturc or established in theory, suggeses that the uni verse is implacably progressing toward final dark ness and decay. There is an importane philosophical corollary ! this view. For if the universe is running down ant nature's processes are proceeding in just one direc tion, the inescapable inference is that everything had a beginning: somehow and sometime the cosmic processes were started, the stellar fires ignited, and the whole vast pageant of the universe brought into being. Most of the clues, moreover, that have been discovered at the inner and outer fronticrs of scicntific cognition suggest a definite time of Creation. The unvarying rate at which uranuum expends ir nuclear energies and the absence of any natural process leading to its formation indicate that all the uranium on earth must leave come into cristcncc at one specific time, which, according to the best calculations of geophysicists, was about two billion years ago. The tempo at which the wild cherno. nuclear processes in the interiors of stars transure inatter into radiation cnables astronomers to conspute with fair assurance the duration of stellar life, and the figure they scach as the likely average age of most stars visible in the firmament today is the billion years. The arithmetic of the geophysicists and astrophysicists is chus in striking agreement us ath ·THE UNIVERSE AND DR. EINSTEIN that of the cosmogonists who, basing their calculations on the apparent velocity of the receding galaries, find that the universe began to expand two billion years ago. And there are other signs in other arcas of science that submit the same reckoning. So all the evidence trac points to the altimace annskilation of the universe points just as definitely to an inception fixed in time. Even if one acquiesces to the idea of an immortal pulsating universe, within which the sun and earth and supergiant red scars are comparative newcomers, the problem of initial origin remains. It merely pushes the simc of Creation into the infinite past. For while theorists have adduced mathematically impeccable accounts of the fabrication of galaxies, stars, star dust, atoms, and even of the arom's components, acry theory rests ultimately on the a priori assumption that sometbing was already in existencamı hecher free neutrons, etiergy quanta, or sumply the blank inscrutable "world stuff," the cosmic essence, of which the multifarious universe was salscquently wrought.

·No text on this page.

·Cosmologists for the most part maintain silence on the question of ultimate origins, leaving that issue to the philosophers and theology. Yet only the purest empiricists among modern scientists tuin their backs on the mystery that underlies physical realıry, Einstein. «hose philosophy of science has sometimes lcen criticized as materialistic, once said: "The most beautiful and most profound emotion 1c can cxperience is the sensation of the mysticil. It is the sower of all truc science. He to whom this cmotion is a stranger, who can no longer wonder Ind send raprin awc, 15 as gond as dead. To know that shat is smpenetrable to us really exists, manifesting itself as the highest wisdom and the most radtane beauty which our dull faculties car comperchemel only their most primitive forms--this hnouledge, this feeling is at the center of true religiousness." And on anaxher occasion he declared, "The COStrite religious experience is the strongest and noblest mannspring of scientific research." A fost scientists, when relerring to the mysteries of the universe, its +357 forces, its origins, and its rationality and hjftrony, tend to avoid using the word God. Yer Ein- ·THE UNIVERSE AND DR. EINSTEIN stein, who has been called an atheise, has no such inhibitions. "Aly religion," he says, "consists of a humble admiration of the illimitable superior spirit who rereals himself in the slight details we are ablc to perceive with our frail and feeble minds. That deeply emotional conviction of the presence of a superior reasoning power, which is revcaled in the incomprehensible universe, forms my idea of God." So far as science is concerned, there are at the moment two gateways which offer the promise of closer access to physical rcality. One is the great NCW telescope which soon, from Palomar Mountain, California, will project man's vision into decper abysses of space and time than ever were dreamed by astronomers a generation ago. Till now the erfreme range of telescopic perception has cssentially terminated at the faint hurrying galaxics 500 million light years away. But the two-hundred-inch reficcfor of Palomar will double that ringe, cnabling man ro look upon whaterer lies beyond. Perhaps it will reveal only new homogencous occans of space and new myriads of far galaries whose antiquc light has sium to earth through a billion years of terrestrial cime. But it may rereal other thingspariations in the density of matter or risual cvidence of a cosmic cirriturc from which man fan accurately compute the dimensions of the universe in which he so insignificantly dwells. The other gateway to this knou ledge may loc opened by the new Unified Field Thicory with Which Einstein has crowncd his cfforts of the last quarter century. Today the outer limits of man's 11B ·THE UNIVERSE AND DR. EINSTEIN knowledge are defined by Relativity, the inner limits by the Quantum Theory. Relativity has shaped all our concepts of space, time, gravitation, and the scalities that are too remore and too vast to be perccued. The Quantum Theory has shaped all our toncepts vi the nom, the basic units of wattes anu! energy, and the realities that are too elusive and ino small to be perceived. Yet these two great scientific ysteme rest an entirely different and unrelated thericccical foundations. They do not, as it were, speak the same language. The purpose of the Unified Field Theory is to construct a bridge between them. Be lieving in the harmony and uniformity of nature, Einstein las cvolved a single edifice of physical laws ** encomass both the phenomena of the arm and the phenonena of outer space. What uncupected new aspects of nature the Unific field Theory may uncover and how many old misseries it may resolic it is still too early to predict. But is obvious minimum achievement is thar it unites the laws of gravitation and the laws of electromagnetists within one byssic superstructure of universal law. In the same way that Relativity secacce gravitational force to a geomystical property nf the space-time continuum, the Vnificd Field Theore relico clectromagnetic force-the other SICOP unisersal force-to equivalent starus. "The sches that there are main structures of space indotendent of cach other, the metric-gravitational and the clectromagneoc," Fonsecin once olxerved, "is furnlerable to the theoretical spirit." Yet despite all his efforts tie could not incorporate clectromagnetic ·THE UNIVERSE AND DR. EINSTEIN field laws into General Relativity. Now after thirtythree years of exploring endless gambits of mathe- 57atical logic he appears to bare achieved his purpose. One may ask if this proves then that clectromagnetic and gravitational force are physically the "same thing." It would be no more accurate to make such a statement than to assert that steam, ice, and water are the same thing though all are manifestations of the same substancc. iVhar the Unified Field Theory does do is to show that gravitational and electromagnetic force are not independent of each other--that they are in a very real physical sense inseparablc. llore specifically it describes gravitational and clectromagnetic force in terms of a deeper reality that undergirds both basic universal field within which gravitational and electromagnetic fields are merely particular cpheincral forms or conditions of state. If the fullest implications of the L’nified Fielu Theory are sustained by the tests of the fururamsf the laws of quantum physics can also be derived from its equations-crucial new insights will doubsless be attained into the composition of matter, the structure of the clementary particles, chcánechanjes of radiation, and other cnignias of the subatomic world. Yet these will be essentially by-products. For the great philosophical triumph of the Unifici Field Theory is implícit in the first word of its riclc. It mrries to logical fulfillinent the long course of science towards the unification of man's concepts of the physical world. Through the centuries the varied currents of discovery, theory, rescarch, and 120 ·THE UNIVERSE AND DR. EINSTEIN reason bare steadily converged, mingled, and flowed onward into crer widening and deepening channels. The first long advance was the reduction of the s orld's multifarious substances into 92 natural elements. Then these elements were reduced to a few fuodamental particles. Concurrently the various "forces" in the world came to be recognized one by onc as varying manifestations of electromagnetic force, and all the different kinds of radiation in the universe--lighi, liest, X-rays, radio waves, gamma ray--35 nothing more than electromagnetic waves of varying wavelength and frequency. Ultimately the features of the universe distilled down to a few basic quantities-space, time, matter, energy, and gravitation. But in Special Rclacivity, Einstein demnnstrated the cqur alence of matter and energy, and in General Relanty lie showed the indivisibility of the space-ruzne continuum. The Unificd Field Thcon now cwmnares and climaxes this coalescing process. For from its august perspective the entire universe is revealed as one clemental field in which cach star, cach acom, cach wandering comet and sluw-wheeling galssy and flying electron is scen to lic but a nipple or tumescence in the underlying spacc-etine unity And 59 3 profound simplicity sužplines the surface complexity of nature. The dronctions färscen grarnacional force and clecfromagnetic force, mancr and energy, clectric charge and field, spuct and time, all fade in the lighe of the cerealed rełtionships and tesolve into configurations of the four-dimensional continuum #luck as the universe Thus all man's perceptions of ·THE UNIVERSE AND DR. EINSTEIN field laws into General Relativity. Now after thirtythree years of exploring endless gambits of mathematical logic he appears to have achieved his purpose. One may ask if this proves then that electromagnetic and gravitational force are physically the same thing," It would be no more accurate to make such a statement than to assert that stcam, ice, and water are the "same thing"-though all are manifestations of the same substance. Ithat the Unificd Field Theory does do is to show that gravi. tational and electromagnetic force are not independent of each other that they are in a very real physical sense inseparable. Alore specifically it de scribes gravitational and electromagnetic force in terms of a dceper reality that undergırds bochbasic universal field within u lich gravitational and electromagnetic fields are merely particular cphc07- cral forms or conditions of state. If the fullest implications of the Unificd Fick Theory are sustained by the rests of the future.it the laws of quantum physics can also be derred from its equations crucial neu insights url donkeless bac atrained into the composition of matter, the structure of the clementary particles, ticaricchan. ics of radiation, and other cnigmas of the subatomic world. Yet these will le essentially by-products. For the great philosophical triumph of the Unifica Field Theory is implieit in the first word of its title It carries to logical fulfillment the long course of science towards the unification of ill's concepts of the physical world. Through the centuries ac varied currents of discorcry, theory, research, ani 120 ·THE UNIVERSE AND DR. EINSTEIN reason have steadily converged, mingled, and flowcu onward into ever widening and decpening channels, The first long adrance was the reduction of the world's mulafarious substances inro 92 suurural cicments. Then these elements were reduced to a few fundimental parricies. Concurrently the various "forces" in the world came to be recognized one by one as varying manifestations of electromagnctic force, and all the different kinds of radistion in the universammlight, hair. X-rays, radio waves, gamina rays-25 nothing more than electromagnetic waves of varying wave length and frequency. Vltimately the features of the universe distilled down to a few basic quantities--space, time, matter, energy, and gravitation. But in Special Relativity, Einstein demonstrated the equivalence of matter and energy, and in General Relativity he showed the indivisibility of the space-cime continuum. The Unified Field! Theory now culminates and climaxes this coalescing process for from its august perspective the entire universe is revealed as ane elemental field in which cich star, each atom, each wandering comet and slow-wheeling galaxy and flying electron ss scen to bc but a ripple or tumescence in the underlying spacc-time unicy. And so a profound simplicity supplants the surface complexity of nature. The distinctions between gravitational force and clectromagnetic force matter and cnergy, clcctric charge and field, space and time, all fade in the liglit of their revealed relationships and resolve into configurations of the four-dimensional continuum which is the aniverse. Thus all man's perceptions of 121 ·purpose. One THE UNIVERSE AND DR. EINSTEIN field laws into General Relativity. Now after thirtythree years of exploring endless gambits of mathematical logic he appears to have achieved his may ask if this proves then that elec. tromagnetic and gravitational force are physically the same thing." It would be no more accurate to make such a statement than to assert that stcanı, ice. and water are the "same thing though all are manifestations of the samc substance. Ithat the Unified Field Theory docs do is to show that gravi. tational and electromagnetic force are not indopendent of each other that they are in a rcry real physical sense inseparable. Alore specifically ir dc. scribes gravitational and clectromagnetic force in terms of a decper reality that undergırds borh-- basic universal ficld within wluch gravitational and clectromagnetic ficlds are merely particular ephemcral forms or conditions of scate, If the fullest implications of the Unified Field Theory are sustained by the tests of the future-jf the laws of quantum physics can also be derivca from its equations crucial new insights will doulit- Icss be attained into the compassion of Buafrer, the structure of the elementary paracles, the cchanics of radiation, and other cnigmas of the subatomic world. Yet these will be csscntally by-products. For the great philosophical triumph of thc Unified Field Theory is implicit in the first word of its citic. It carrics to logical fulfillment the long course of science towards the unification of man's concepts of the physical world. Through the centuries olie varied currents of discovery, thcory, rescarch, and 1712 ·THE UNIVERSE AND DR. EINSTEIN skull predestines the outlines of the tissue it supports, there is no likeness between the image of a tree transcribed by our senses and that propounded by wayc mechanics, or between a glimpse of the starry sky on a summer night and the four-dimensional continoum that has replaced our perceptual Euclidean space. In trying to distinguish appearance from reality and lay bare the fundamental structure of thic univcrse, science has had to transcend the "rabble of the senses." But its highest edifices, Linstein has pointed out, have been "purchased at the price of emptiness of content." A theoretical concept is emptied of content to the very degree thar it is divorced from sensory experience. For the only world man can truly know is the world created for hum by his senses. If he expunges all the impressions which they translate and memory stores, nothing is lefe. That is what the philosopher Hegel meant by liis cryptic reinark- "Pure Being and Nothing are the same." A state of existence desoid of associations has no meaning. So paradoxically what the scientist and the philosopher call the world of 2p pearance--the world of light and color, of blu shics and green leaves, of sighing wind and murmuring water, the world designed by the physiol. ogy of human sense organs--is the world in which finite man is incarcerated by his essential nature. And what the scientist and the philosopher call the world of reality--the colorless, soundless, impalpable costlos which lies like an iceberg beneath the ·THE UNIVERSE AND DR. EINSTEIN the world and all liis abstract intuitions of reality merge finally into one, and the deep underlying unity of the universe is laid barc. The Unified Field Theory touches the "grand aim of all science," which, as Einstein once defined jt, is 'to cover the greatest number of empirical facts by logical deduction from the smallest possible number of hypotheses or axions." The urge to consolidate premises, to unify concepts, to penetrate the variety and particularity of the manifest world to the undifferentiired unity that lies beyond is not only the leaven of science, it is the lofticst passion of the human intcllect. The philosopher and niyscic, as well as the scientise, have always sought through their varinus disciplines of increspection to arrisc at a knowledge of the ulcssnate amurable csscnice that undergırds the mucable illusory world. Alorc than twenty-three hundred years ago Puro de clared, "The true lover of knowledge is always striving after bomg. . . . He will not rest at those multitudinous plienomena whose existence 15 p. pearance only." order emerges But the irony of man's quest for reality is that as nature is stripped or its disguises, from chaos and unity from diversity, as concopes merge and fundamental laus assume inercisingly simpler form, the evolting picture licconies cier more remore from experienccmofar stranger mdeed and less recognizable than the bone structure lic. hind a familiar face. For where the geometry of a 122 ·THE UNIVERSE AND OR EINSTEIN may appear as distorted to posterity as that of their predecessors seemed to them. . For all the promise of future revelation it is pos. sible that certain terminal boundaries have alrcady been reached in man's struggle to understand the manifold of nature in which he finds himself. In his descent into the microcosin he has encountercd indeterminacy, duslity, paradox-bassicts that seem! to admonish his he cannot gry spo mnquisiuively into the heart of chings without altering and vitiasing the processes he seeks to observe, and in or ploring the macrocosms ke coses at last to a final featureless umty of space-time, mass-energy, 22- ter-field an ultimate, undiversified, and ctcrnal ground beyond wuch there appears to be nowhere to progress. The prison house," said Plato, “is túc world of sight." Every seeming avenue of escape from this prison house that science has surveyed leads only deeper into a misty realm of symbolisin and abstraction. may be that the extreme and insurmountable limit of scienpfic knowledge will be reached in the aetainment of perfect isomorphic representation that is, in a final flawless concurrence of deory and natural process, so complete that every observed phenomenon is accounted for and nothing is left out of the picture in its approach to this goal, sci. ence has hitherto achicved sis most notable prag. matic and operational triumphs. For while telling nothing of the true "nature" of things, it neverthe ·THE UNIVERSE ANO DR. EINSTEIN plane of man's perceptions mais a skcleton structure of symbols. And the symbols change. While physicists of the last century knew, for examplc, that she crimson of a rose was a subjective, jesthetic sensation, they believed that "in reality" the quality they formed crimson was an oscillation of the luminifcrous ether. Today it is conventional to identify crimson as a wave length. But it is cqually proper so think of it as the value of the chergy content of photons. Such considerations lcd a famous physicist to remark cynically that on Mondays, Wednesday's, and Fridays onc uses the quantum theory, and on Tuesday's, Thursdays, and Saturdays the wave licory. In cithics casc the concepts employed arc abstract construcrions of theory. And sipon examination such concepes as gravitation, electromagnetism, energy, current, momentum, che atom, the actitron, 3}} turn out to be theoretical substructures, inventions, icraphors which man's intcllccr fuas contrived ro help him picture the truc, the objective really lic apprehends bencach che surface of things. So in place of the deceitful and chaotic representations of thic senscs science has substituted varying systerns of symbolic representacion. 11c thiese systems are distinguished by constantly increasing mathemuzeí. cal accuracy, it would be difficult today to fisid any scientist who imagines tumself, because of his ability to discem previous crrors, in a position fi» cnuncutic final truths. On the contrary, modern thousats are awarc, as Newton was that they stand on the should ders of giants and that their particular perspecine 124 ·THE UNIVERSE AND DR. EINSTEIN may appear as distorted to posterity as that of their predecessors seemed to them. For all the promise of fucure revelation it is fossible that certain terminal boundaries have already been reached in man's struggle to understand the manifold of nature in which he finds himself. in his descent into the microcosm he has encountered indererminacy, duality, paradox-barriers that seem to admonish him he cannot pry too inquisitively into the heart of things without altering and vitizeing the processes he seeks to observe. And in ckploring the macrocosm he comes at last to a final featureless unity of space-time, mass-energy, mat. ter-field-nul mare, undersificd, and eternal ground beyond which there appears to be nowhere co progress. “The prison house," said Plato, "is the world of sight." Every seeming avenue of escape from this prison house that science has surveyed leads only deeper into a misty realm of symbolism and abstracrion It may be that the extreme and insurmountable limit of scientific knowledge will be reached in the artainment of perfect isomorphic representation thac is, in a final flawless concurrence of theory and narural process, so complete that every observei phenomenon is accounted for and nothing is lef out of the picture. In its approach to this goal, sci ence has hitherto achieved its most notable prag matic and operational triumphs. For while tellin nathing of the true "nature" of things, it neverthe ·THE UNIVERSE AND DR. EINSTEIN Jess succeeds in defining their relationships and depicting the events in which they are involved. "Thic cyeni, " Alfred North Whitchcad declared, "is the unit of things real." By this he meant that however theoretical systems may change and however coipty of content their symbols and concepts may be, the csscntial and enduring facts of science and of life are the happenings, the acciricies, the events. Thica implications of this idca can best bc illustrated by contemplating a simple physical crent such as the meeting of two electrons. Within the frame nt modern physics one can depict this crent as a collision of two clcnicntasy grains of matter of twn clementary units of clcctrical cnergy, as 3 concourse of particles or of probability waves, or as a com mingling of eddies in a four-dimensional spacc-time continuum. Thcory docs not define what the prin cipals in this encounter actually are. Thus in a sense the clectrons are not "real" but merely theoretical symbols. On the other fund dhic mccring itself is "real"mthc event is "rcal." It is as though the cruc objcctire world lies forever half-concculcd bencark : translucent, plastic dome. Peering through irs cloudy surface, deformed and distorted by the ever changing perspectives of slicory, min faintly espics certain apparently stable relacionships and recur. ring events. A consistent isomorphic representation of these relationships and crents is slie maximal p$ sibility of his knowledge. Beyond char pomni lic starcs into the roul. In the crolution of scientific thought, one fact fuis become impressively clear: there is no mystery HA ·10 THE UNIVERSE AND DR. EINSTEIN of the physical world which does not point mystery beyond itself. All highroads of the intellect, all byways of theory and conjecture lead ultimately to an abyss that luman ingenuity can never span. For min is enchained by the very condition of his Iseing, his finiteness and involvement in nature. The farther he extends his horizons, the more vividly hc recognizes the fact that, as the physicist Niels Bohr puis "we are both spectators and actors in the grear drama of existence.” Man is thus his own greatest mystery. He does not understand the vast veiled universe into which he has been cast for the reason thar he does not understand himself. Hle comprehends but little of his organic processes and even less of his unique capacity to perceive the world about him, to reason and to dscam. Least of all does he understand has noblest and most myste rious faculty, the ability to transcend himself and perceive himself in the act of perception, Mfan's inescapable impasse is that he himself is part of the world he seeks to explore, his body and proud brain are mosaics of the same elemental particles that compose the dark, drifting dust clouds of Interstellar sprace, he is, in the final analysis, merely an ephemeral conformation of the primordial spacetime field. Standing midway between macrocosm and microcosm he finds barriers on every side and con perhaps but marvel, as St Paul did nincteen hundred years ago, thar "the world was created by the word of God so that what is seen was made out of things which do not appear."

·No text on this page.

·Reading List The last does not include all the sources consulted in the preparation of this booh; si does, however, encompass the major sources of material plus some related volumes that might be of interest and value to the reader who wishes to explore further areas of this field. The Development of Physical Thought by Leonard B Loeb and Arthur S. Adams. John Wiley & Sons, Inc., 1933. A survey course of modern physics. Comprchcasive, beautifully written, and as enjoyable to the lay reader as valuable to the student Specific discoveries of the last decade are, of course, not represented, otherwise a superior history of science The Dust Cloud Hypothesis" by Fred l Whipple, Sciendific Anterican, May 1948 It should be noted that the new Scientific American is no longer a gadget and hobby magazige Under new management it now presents artcles of fundamental scienufc importance, brilliantly cexed fos stelligent Saymes. Einstein, His Life and Times by Philipp Frank. Alfred A, Koopt, 1947. The best biography of Einstein, by a former colleague and eminent physicist. Detajled exposition of Einstein's scientific conurbutions as well as lively dio graphical and personal details. The Evolution of Physics by Albert Einstein and Leopold Infeld Simon and Schustet, 1942. The gronth of ideas from early concepts to Relativity and quantă, simply and fascinatingly described No mathematics.

·THE UNIVERSE AND DR. EINSTEIN The Expanding Universe by H. P. Robertson. Reprint from Science in Progress, Second Series, clear, detailed, and interesting discussion of the structure of the universe by a famed cosmologist. Explaining the Atom by Selig Hecht. The Viking Press, 1947. Unsurpassed as an exposition of the bistory and the theory of the atom. Wattea by a famous biophysicist for the layman, Flights from Chaos by Harlow Shanley. 11Hurlesey Hlouse, 1930. A fascinating survey of the universe and its comiponent parts from atoms to galaxies by Harvard's distinguished astronomer. This book is unlortunately out of print, but should not be, "Galaties in Flight by George Gamo», Scirnufic Ameri- «an, July, 1948. See note under "The Dust Cloud Iy** pothesis" above. Afeel the Atoms by O R Frisch. A A Wy2, Inc., 1917. popular guide to modern physics. Amusingly writica by a noted atomuc physicist. Atend and Natire by Hermon West Von erity of Pennsylvania Press, 1934. The epistemological implications of modern physies set forth by a great thcorist and colleague of Dr. Einstein. The philosophical standpoint from which the present iolume is usutten is derived to great measure from this small but remastable boi, comprising five lectures del cred by Dr Weyl At Swarthmore College in 1933 Modern Physics by GE SI launcey D Van Kontrand Company, Inc., 1945. Up-to-the-minule let, ancluding sections on nuclear physics, radioactus), comic says, and the like. Also chapters on astrophywo. Relativity, and the philosophical implications of modern science In ·2 THE UNIVERSE AND DR. EINSTEIN dir. Tompkins in Wonderland by George Gamow. The Macroellan Company, 1947. Prisciples of Relativity and Quantum Theory set forth in an iazentous (ramet ork of 13:rative fiction. The Mysterious Universe by Sir James Jeans. The Macmillas Company, 1932 A classic which has awakened thousands of readers to the relationship between science and philosophy. The Nature of the Physical World by A. S. Eddtogton. The Hacmillan Company, 1928. Required reading for anyone interested in this field One Two Three .., Infinity by George Gamow. The Viking Press, 1947. An eclectic account of facts and theories about the universe in its microscopie and macroscopXc manifestacions, described by a lopflughs broteins? physicist who is also the ablest and most entertaining expositor of science writing soday. Physics and Philosophy by Sir James Jeans. The Macmillan Company, 1943. A further discussion of the changing concepts of modern physics and their philosophical im plications. Relativity, The Special and General Theory by Albert Einstein Henry Holt & Co., 1920 Lucid and detailed. Some mathematscs, but not too dificult, Science and the Modern World by Alfred North Whitehead The Macmillan Company, 1925. Another classic, also required reading

·No text on this page.

·Appendix In Theoretical Physics there are often several ave... nues of approach to a given concept. The exposition of the principle of the increase of inertial mass an pages 66-68 follows a quickly comprchended pattern analogous to those employed by many college zihysics texts. Readers with some mathematical equipment may wish to read Dr. Einstein's develop ment of this principle as set forth in his book Relatorty, the Special and General Theory. Some esscn. tial excerpts follow, quoted with permission from Peter Smith, Publisher, "The most important result of a general character to which the Special Theory of Relativity has led is concerned with the conception of mass. Bc. fore the advent of relativity, physics recognized two conservation laws of fundamental importance, namely the law of the conservation of energy and the law of the conservation of mass; these two fundamental laws appeared to be quite independent of cich other. By means of the theory of relativity they have been unued into one law. . . . "In accordance with the theory of relativity the kincric energy of a material point of mass m is ne langer given by the well-known expression mo inc but by the expression ch

·THE UNIVERSE AND DR, EINSTEIN
"By means of comparatively simple considere
tions we are led to draw the following conclusion
A body moring with the velocins, which absorb
an amount of energy Em in the form of radiation
without suffcring an alteration in velocity in thi
process, has, as a conscqucnce, its energy increase
by an amount
"In consideration of the expression given alkava
for the kinetic cnergy of the body, the requirci
energy of the body comes out to be
(m + c
ri
3111Qunc
"Thus the body has the same energy as a body
of mass
(m +..) moving with the vclocity ::
Hence we can say. If a body cakes up an amount of
cnergy Eu then its inertial 11385 increases by an
E.
the inertial mass of a body is not a
constant, but varics according to the change in the
energy of the body. The incrrial mass of a system
of bodics can cren be regarded as a measure of irs
Chesgy. Thic law of the conservation of the mass of
1 system becomes identical sich the law of consora
vation of energy

·Acceleration, and mass, 66, Descartes, 24, 44-45 St fi. Determinism, 37 Action-zt-a-distance, 90 Duality of nature, 29 ff. Age and relativity, 65 Dust cloud hypothesis, 112 Archimedes, 13 Arcturus, 52 Eddington, Sir Arthur, 26 Aristotle, 17 Einstein, Albert, 23 fi. Atom, 15, 16, 19, 20, 30, 31, beliefs ahout universe, 39, 64, 69, 110, 112, 184, 115, 119, 125 on common sense, 63 on religror, 39, 117-18 Berkeley, 24721 on tune perception, so fi. Beta particles, 68 photoelectric 11, 28-30 Bohr, Niels, 127 rejection of ether theory, Born, Max, 32-33 49 de Broglie, Louis, 30-3? theory of general relativity, 101 ff. Cause and efiect, 37, 111 Costsifugal forte, 87, 88 Colar perception, 27, 51. 124 Companion of Sirius, 93 Continuum, 13 ff. Cosmic 12, 22, 23. 113 Cosmology, ke Universe Creation of universe, 114, 115 theory of specsal relativity, 13-14, 49 ff. 71 unified field theors, 14, 16. 118 ft. Essstein effect, 99 Electsscal held, 90, 121 Electricity, 15, 16-17. 48.90 Electromagnetic field, 15, 99, 119 Electromagnetic waves, 22. 123 Electrocaanctista, S. 119, 120, 12+ Davison, C. J., 35 Democritus, 20 Desiry Systern, 23 ·THE UNIVERSE AND DR, EINSTEIN Electron, 24. 27 ff., 36, 38, Free will and modern science 68, 70, 105, 110-11, 38 112-13, 116 Energy', 16, 68 ft., 121, 124 Galilea, 13, 37, 30, 42, 49 of quantum, 25, 124 82 radiant, 25, 28 Gamma says, 22-23, 37, 11: Entropy, 111 ff. Gamor, George, 109 Equation, General theory of relativity: Eh, 25 Emra, 68, 69 Gemmer, L. II., 31 2 km, 31 G-Lord, 88 El 68 Gravitation, 14-176 71. 78 81, 82 ff. 119-21, 124 mo 67 and absolute motion, 88- 89 Equations, de Broglie's, 31 and Luchdean geonistry, Lorentz transtormation, so 103 mass-energy relation, 68 and space-time continuum, maks-elocity selarinn, 67 78, 119 quantum ener, 25 cficct on light, 94 fi. Equivalence of gravitation Einstein's fases, 87, 92-174 and inertia principle, muivalence of incrtia and, 88 ff. 83. 88 ff. Ether theory, 45 fi. Veus con's lan, 43, 81-83, Michelson-Sorley expert S94, 100 ment, 45-48 Gravitational field 89, 91- Euclid, 13, 101, 133 92, 94, 06 fi. 120 12/6 Taraday, Jlichsel, 15, 145,01 Forre, inertial, 88 . Fosdict, II. E, 13 Four-dimensional space-time continuum, 73, 121 l'ourth dimension, 74 fi. Hensenters. 1. 11.36 Ilirsira, 11 }lubble, .ds in 195 {ung, Day 13, 14 Irestia, 66, S1 si ·equivalence of graritation Lorentz, H. A., 36 ff. and, 83, 88 ft. Infinity, 100-01, 104 ff. Siagnetic field.go31 infra-rpd 13, 22 Magnetism, 15-16, 48, 9; Interierometer, 46-48 ste aisa Electromagnetlies, H. E., 64 iem dlass, and energy, 68 fi. Jeans, Sir Jantes, 30-32, 104 and relativity, b6 ff. ard clocity, 66 f. Mathematics, as basis of mol Law, gravitation, Einstein's, em concepts of uniserse, 89, 92-34 19-20, 24 ff., 38-39. gravitation, Newton's, 43. 56-60, 123 ff 82-93, 89-24, 100 Mlatter, 15, 16, 20, 21, 26. inertia, 81, 88 f. 68-70, 105, 120 phorelectric effect, 29-30 Matzer, and space-time conthermodynamics. 211 tinuum, 103-04 transformation, 53 2,56 Marell, J. Clerk, 31-32, 45.00 flaws of nature, unitormity. Mercury (planet), 52, 93-94 80 fi. ATetaphysics and modern Leibnitz, 21, 50 physics, 20 $ Lemaitre, Abbé, to Afichielson, A. A., 45 ft. Light, 19.22, 26 # 35.45 ff. Alichelson-Morley interier- 54-55, 95-96 orheter, 46-47 and grilitation, 94 ft. Afinkowski, Herman, 6 deflection of starlight in Molecule, 31, 109, 111 T21itational field of Iloriey, E. W., 45 6. tun, 94-438 Motron, stisnlute, 79. 80, 89 diffraction, 29 89 splocity, 46-47. 49, 50, 51 and laws of transform: 57, 58,62 tron, 53 ff., 62 wie length, 22 h (Lpltjes?, 52 49, 61, 66, 79 fi., 881 Lirke. Jakin. 11. 20. 21 nomaitorm & R.O and relativity, 41-43, 4 ·THE UNIVERSE AND DR. EINSTEIN Nature, duality, 30 ff. plotoclectric effect, 28 functional harmony, 24 quintum, 25-27 lairs of, uniformity, 60, uncertaints, 35-37 80-81 Procon, 28 mathematical description, Proton sinchrotron, 69 19-20, 24 fi. 124 Neutron, 28. 109 Newton, Isaac, 13, 19, 42 ff., Quantum theory, 19, 25 f1. 119 81 fi. on solar systein, ++ on space, ** Radiation, and matter, yo 112, 114 Oersted, H. C, 15 and quantum theary, 25 electromagnetic, 22-23 salar, 22 Perceptions, see Sense percen Radioactity, 19, 68, 69 rions 113-15 Photoelectric effect, 26 ff. Radio 25, 22-23.52 Photoelectric law of I instein, Radium, 6x2 28-30 Reality, 17 ff., 64, +18 fi. Photon, 28, 37, 1870, 105, and four-dimensiona II2 space-time consimuuns, P'ls siologic processes, musela 77-78, 121 ativity, 65 and quantuns physies, 35, Planck, Mar, 25 28, 12-23 Planck's Constant, :5-26,31, and relatrat), 0); fi 37 Arutotelin, 17 22. 125 Fimtein's que for, 3), thritron, 112 113 Principle, Galilean, of sela Venstemuan. 17-18 tivity, 42 Relativity, 14 1'3 #1, #2-1. gravitation and inertia 49 fi, 7. a. 1 ff. 79 fi. 88 fi Ven tonian, of relatssits, ans plinise »)*811 14, +3 Guivalence, SS fi.

·THE UNIVERSE AND DR. EINSTEIN Einstein's general theory and dust cloud hypothesis, of.71 . 112-13 Einston's special theory and space-time continuum, of, 14.49 ff., 71, 79-80 7677,90 Locke on, 41 light of, in sun's gravitaof mysition and motion, tonal Keld, 96-98 41-42, 57. 79 ff., SS. Sun, temperature of, 109 of simultaneity, 52 #. Religion and science, 117 fi. Television, 28 Robertson, H P., 108 Thales of Miletus, 16 "Russell, Bertrand, 27 Theory, ether, 44 fi. quantum, 19, 25 ft.119. 12+ Schrödinger, E., 3. fi. unified field, 14, 16, 119 ff. Science, aim of, 16, 17, 13. wave, 28 ff., 124 122 Themodynamics, second law and plufosophic thought of, 112 20-22, 122 Teenc, 25-22, 50, 63 ff., 73 and reality, Ear 18,118 R. ff, 121 and religion, 117 ah salute, 50 f. # Sense perceptions, 20 ff, 38, and relativity, 50 H., 58, 51, 63-64, 123 01ff multanesty, 52 F. as form of perception, 51 space, 21, 49.,65 1,73ff, ** fourth dimension, 75 ff. 123 effect of grasstation on, Space, absolute, sa f 98 ff. and relativity, 49 f1, $8 Einstesn's definition of, connuum, 73 ff. 50 A $8 defined by Leibnitz, 50 Veston's ideas on. + Time-space continuum, 73 Spractime continuum, 73 ff. ff119 ff. , 92, 101, 12 Tolman, R, C., 110 Cu Tocop, 28. 64, 78, 108 Transformation laus, 53 #. noza, 24 Stass at a, 13 solar, 51, 77 Ultraviolet rays, 22 ·THE UNIVERSE AND DR. EINSTEIN -- Uncertaints's principle of, Uranium, 20, 69, 114 36-38 Vniſed field theory; 34. Il, Velocity, of light. 10 ff., 54 118 f. 55. 57-58, 02 Universe, and Euclidean ge. of carth through ether, 48 ometn, 10% ff. of clectron, 68 and mathematical princiof sound, 57 ples, 27, 38-39, 122 . average density of mastes Wave length, of electron, 31 111, 303 of moleculs, 31 expansion of, 107 ff. fundamental forces, 14, . of variou types of radiaation, 22 70-71, 119 of visthle light, 32 infinity of, 104 fi. in light of Ernstein's the. Wase mechanics, 31, 123 aries, 50, 63-674, 7! ff., Wave thrors, 28 ff., **.70, 0, 92, 100 ff. 124 mechanical, 17 f1, 43,44 ff., Waves, electromagnetic. 21 89 Veght, 66 Newtonian, 43, 44 $., 64. Innle, F. LA 112 }}'Hitchcad, A. N., 125-26 71, 100 origin, theories, iog radius of, sos X-1233, 27-33.36-37 ·MENTOR BOOKS are the best books in dozens of fascinofing fields including sociology, anthropology, the clossies, psychology, mature, science and philosophy, in formolive and authoritative, these editions offer the intelligent reader on inyalsobie opportunity to assemble o distinguished brory of little cost, ONLY 35 CENTS EACH it AIMS OF EDUCATION WE AUTOBIOGRATHY OF AN Ex-COLOURED MAN Alfred North Akirkeod. Edo. estion as an intellectual proc. James Weldon Johnson. A modern clasefe, this is one al en for the students a pro the first book on the Agro lessor Whitebead's goal El an America-the vivid story of keneral theory of education is man who crotsed the rolar and stitulating isgairy Bse. (#$129) ioso parallel fields. (#1:41) BALLET (Bettet in America George Amberg A rarvey of AMERICA IN PERSPECTIVE tabridge) American ballet from the early days of theatrical dant Edited by Henry Steele Com. ang to the prestol, st includes moger, Srímulating commen tro oragael libretis by Rode tary on Atterscans and how bins and de Mille. With se they behave by 1 scuse and Hected instration from the clothbound editios. #M42) percepire loreignets from de Torqueville 19 Matthew As nold and Dean W. Brogan. BEETKOYEN J. W. N. Sulliran A prolonnd analysis of the theory of art in the ligbe of modern ses. AMERICAN ESSAYS ence, and a penetrating mody of Steihorealisogeli, #11:51 Fded by Charles 0 Share The growth of America BIOGRAPHY OF THE EARTH through the eye of Emerroa, Twain, Mracker and other George Gomor. The takisat may writers. (1926) 198 lfe Nory of the planet Eanh, prolasele lusimzied. #127) ARTS AND THE MAN COMING OF AGE IN SAMOA Irkin Edman A brilliant pkite Ineopher explains how to an Margaret Mead. A mout derstand o play the arii. fladt af Adalescezet in the South Pacific by a sisted asthropologia. (* A11 ·THE DEMOCRATIC WAY OF LIFE HOW TO KNOW AMERICAN T. 1. Smith and Eduard C. AHTIQUES Lindeman. (A new and com Alice Fischer. This di pletely revised edition) A Lightlal ladhool tella har challenging book which or to reregnite all (tres of u amines the democratic ideal fol and decorative Amrrira and how it works in practical antiquer. Includes silver, for application. (3159) niture, pewter, china N EMERSOH. THE BASIC WRITINGS OF needlework, 300 drawing By AMERICA'S SAGE Pagline Inmat. 1635 Edited by E.C. Lindeman. HOW TO KNOW THE AMERKCAN Enerron's simulating caya MAMMALS are always current as a bol. levan T. Sanderson. Wha! mask against xnperstition and Sammaleare-how to leniti, mediocrisy (1935) them, where they fire-writ A GALLERY OF AMERICANS Im and illtrated by the Edited by Frank Luther Vott. noled naturalist. 200 katra A virid panorama of the tions (163) American personality at HOW TO KNOW THE BIROS Flimped in the lives of 39 f Roger Tom Peterson. Lin. moue Americans, (1361) drawing and shurifes of GOOD READE over 200 common perle. » Fosted by the Committee on lected from the clarhnund College Reading. An Invalu cdition, 31}uostate this baie *ble guide to the world's breat handbook by a malcil orni. book with a list of 1.250 ree thalogisk. (MG) ommended titles for konso HOW TO KNOW THE WTED reading. (#M761 FLOWERS GREEK HISTORICAL THOUGHT Alfred Steerud. 7 hatte Edited by Arnold / Taynbee and all of wild wife The eminent historian's Esil. thele dixtinxulthinx family liant translations of Greek mark; and Brw to ROW ristorical experience from thes. With futration, he lomcr to the age of lleracliut Sidney Horn wirrtrait from ih iloilound 2on. mastimalasing muide for our own tímco (3172) THE AD THE GREEK WAY TO WESTERN llamar translated by II. CIVILIZATOK Dlouse. A brilliant to Edith Ilomilton, Anotri Iranulation of the story of Creek rcholar recreates Thr Selulire ly = nate nella Golden Age of Greerr, pluri. scholss. (316) datrs the schierements is fit. INDIANS OF THE AMERICAS ersture, trienre. pullorophy art, und derzortacy of flut Jakn Caller Thir fint tot period. (311) in print the full panorams at HET$DI, RACE AND SOMETY the 3r Indian from th terly tryin Palrslithu ip to the pri LC Dunn and Th. Dobihan. rat. *33331 ky. A faveinstiek spy of PNTRODVOND INAVESA CB Blattian retrotinn el Shirnrsrr's Pwa timmar the theatre and dram of 814 در groop diterraces: bow they Arise, the instance of hard. My and earitongtext, and the prosperitet nuze loprerr ment. ($1:43 ·MODUCTION TO ECONOMIC MAY NAKES HIMSELF SCIENCE P. Gordon Chulde. Man's n. rial and technical isolation Georp. Scule. A noted - through 31,000 years of prat. thority explains tow we are lleurring to meature and con rey-ike Srat American esttion of brilliant classic. sol the economie forses bich role ous lises. (158) THE MEANING OF EVOLUTION SFERSON Artised and abridged (revised and abridged} Sarl K. Padoter. One of the George Gaylord Simpson The ben biographies of the great principles and haman m090- American salesman, thus elir ing of erolation, tracing the ring book lominten Seffer. entire span of fire ont rarth mon's life long consc! be and its ethical implications tween by desire for the te for mankind (#3106) tenity of planlalion life and NEW WORLD WRITING bis keen sence of duty to bus First Mentor Selection 502) rountry. 1 #5170) An exciting crocuertion of IN landged) lated poems, plays crinal Darid Shub farinating hi. articles and potion of any. ple by important new writers. ofraphy of the man who from NI$73) bile grave, directs the strategy of the Kremlin today. THE NEXT DEVELOPMENT IN MAN Previsod by the autor 1959) Lancelot Love thvir irt, TE ON OTHER WORLDS poluic, econpmirs and are 11. Spencer Jones oes life pre are integrated into the on other world' A Su. only way of thinking tid deerwasion of this wort shal weil mark the new twer. kuing question #M139) trella cenipry man. An in Higging concept by a tim WE STORIES OF MEN WHO ulating thinler #2150) SHAPED HISTORY from MUTARCH'S LIVES (abridged) THE ODYSSEY Editor rith an introductor Homer, translared by *.X.D. Rouse modern prose irang by Fduard C Lindeman lation of the world's greatest daingnified selection taken from the lalin ons William adventare story, #1121) Lan hornt ramiation. 390 MODERN POEMS #1115) Edited by Selden Rodman. An citing collection of the HE UMITATIONS OF SCIENCE best yosh of American, Eng J, T. Sulltan The boon fish and Europeod wrileri, darien und potentiallies of selected by a distinguished premnt day trientific 09 poet, whose detailed introduc. septs, in layman's language. 11on is a complete antiqe of modern poetry. (#1194) CH UNDERSTANDING SCIENCE WAN IN THE MODEEN WORLD James B Corant. A brilliant Sultan Haslev, 13 stimulating atomit kiegtist, the President **y on the vital rapes of of Harrard Univerny S. toclay. Srlested from fais plains the scope of seience in Van Stand Alone and on our modern world, and its living in Revolution." in historical view of itt 437 Prowls (1168) ·THE OREGON TRAN THE REVOIT OF THE NAS$ Francis Parkman. Introduce Bernard farrs (revised tion by 4. ). Guthrie, Jr., A the author 1919), AN 2011 trao narrative of the dangers and esriemenls enroantered Italite study of the bu ground or the most con by derilmas-care cuplorers in versial country in the ma websted Indian rouary. 137) (151) SCIENCE AND THE MODERN PATTERNS OF CULTURE WORLD Rruh Benedict, An analysis of Alfred Morty Whitehead Our social structure as re penetrating sinds of the Jated to primitire cirilications, fluence of fur centuries (12) *cientife thovih on Mo cirilitation (+21237 PHILOSOPHY IN A NEW KEY Susanne K. Langer. A sady SCIENCE AND THE MORAL LUI of the xymbolism of reason, Mar 6, 0110, Insrodation ritc and art, in clear, reseable E. C. Lindeman. 1 no Myle. (MAS) Aturriean philosopher and a parllire approach to zroy PSYCHOLAYHOLOGY OF In . prlerille *gr. 11113 EVERYDAY LIFE SEX ANO TEMPERAMENT IN Sigmund Freud, Translated Dr A. A. Brill. The perkraird THREE PRIMITY1 Sotirmis *nalyst'e casily understood 3largarrt Hend. As porce explanation of the billen slisy differences betwores CIUNEA of everydsy errors and open linked to their A world lamuua antlıronn siet explores this intrika THE PRINCE furstion. #1136) Niccolo Varkidi plls. Intro THE SUMMINO VY duction by Chrusan Gours. The classic work an . Somierent Jauxham vtalco. marle famou mustsor recarn manıhlp na polisi porer. his view on life **** {#3169) KLCONSTRUCTION IN PHNOSOPHY A WORLD APARS John Derry, Asserici't tau! Cuctse terling A titel, . highly regarded thinkrt ant morbins aresant of Intola Iner low ke phillaunphy of dais labar esto 3. eta experiener can be integrar the *** imprisoned 1314 with contato posary life 3173 #153) THE WORLD OF COPIANO RELIGION AND THE RISE OF CAPITALISH Annus Armitage Thr fan n. 11. Tary. The ladunce sting story of the man ** of religious baaght on the elaimed the earth sarial and trennsie irpe. around the sun á pro tures of the world. (11:?! Ii, 14637 THE NEW AMERICAN LIBRARY OI World Litoraluro 501 Madison Avenue, New York 22, New York

·No text on this page.