Cover image for Einstein's brainchild : relativity made relatively easy!
Einstein's brainchild : relativity made relatively easy!
Parker, Barry R.
Personal Author:
Publication Information:
Amherst, N.Y. : Prometheus Books, 2000.
Physical Description:
280 pages : illustrations ; 24 cm
Personal Subject:
Format :


Call Number
Material Type
Home Location
Item Holds
QC16.E5 P37 2000 Adult Non-Fiction Non-Fiction Area
QC16.E5 P37 2000 Adult Non-Fiction Open Shelf
QC16.E5 P37 2000 Adult Non-Fiction Open Shelf

On Order



Physicist and popular science writer Barry Parker speaks to the broadest possible audience in bringing Einstein's theories to life. Given the fervent renewed appreciation for the contributions Albert Einstein has bestowed on humanity, Parker thinks it only right to dedicate a book to explaining in the clearest possible terms the meaning and beauty of Einstein's theories.

While tracing the story of Einstein's life, Parker seizes on the crucial groundbreaking theories that Einstein envisioned. Not since Isaac Newton had anyone conceived the universe in such a revolutionary, startling new way. Through Parker's eloquence, eye for detail, and clever use of Einsteinian cartoons and vivid illustrations, he enables the reader to see and appreciate for perhaps the first time the full meaning and scope of Einstein's Special Theory of Relativity and General Theory of Relativity.

Parker then guides the reader to the next step in Einstein's revelations: the possibility of time travel. In exploring the fascinating implications of Einstein's thought, Parker treats us to the experience of discovering a black hole, traversing curved spacetime, and greeting our much younger twin who has just returned from a long and arduous spaceflight.

Parker's incomparable gift for language captures Einstein's uniqueness, singular brilliance, and stunning theories. The clarity of the writing coupled with the many illustrations will drive home the point why so many consider Einstein to be the greatest scientist who ever lived and Time magazine named Albert Einstein "Person of the Century."

Author Notes

Barry Parker, Ph.D. was a professor of physics at Idaho State University from 1967 to 1997.

Reviews 2

Publisher's Weekly Review

Space is curved. And time is part of space. And space and time contract as you speed up. Moreover, nothing can go faster than light. Nothing gets out of a black hole. "Acceleration and gravity [are] intimately related." These and other counterintuitive properties of our (expanding) universe all emerged from Einstein's theories of special and general relativity. Their consequences reshaped the world of physicsÄand their complexity has given generations of popularizers plenty of work. The latest book to tackle Einstein's insights and their consequences is also one of the clearest and shortest yet. Parker (Search for a Supertheory, etc.), a longtime professor of physics at Idaho State University, explains Einstein's theories in nonmathematical language, along with their famous predictions, tests and implications. A particularly strong chapter (with a full complement of clean diagrams) addresses the theory and practice of time travel. Parker looks with a friendly eye at the private lives of Einstein and his physicist contemporaries (his first chapter covers "Einstein as a Youth"). But he devotes more space to the life of the universeÄto its initial big bang and to its probable, gradual end. Starting with the 1887 Michelson-Morley experiment (which proved the nonexistence of an invisible, omnipresent stuff called ether), Parker addresses the findings that moved Einstein to his discoveries. Later chapters outline relativity's successors in the march of theoretical physics, notably quantum theory and Heisenberg's principle of uncertainty, which Einstein himself refused to accept. Students and others looking for fascinating and painless introductions to this particular, well-traveled, but still-startling corner of the sciences will be happy with Parker as their guide. (Sept.) (c) Copyright PWxyz, LLC. All rights reserved

Library Journal Review

For an easy introduction to Albert Einstein, the standard is Joseph Schwartz and Michael McGuinness's Einstein for Beginners (1990), a cartoon classic with a Socialist slant. Parker, a former physics professor and prolific science writer (Alien Life: The Search for Extraterrestrials and Beyond), tries his hand at making Einstein's theories accessible to a general audience but falls short of the best efforts in this area. Perhaps the main flaw is that he studiously avoids mention of politics or the atomic bomb yet still tries to take his reader beyond just the science of relativity. The result seems watered down. Parker describes how "hundreds of reporters were soon besieging" Einstein after the confirmation of his theory of relativity, but the reader is left unsure why an unknown physics professor with a theory nobody understood became an overnight celebrity. Parker's scientific writing is nicely done, but the oversimplified diagrams don't help clarify a complex subject. Readers looking for a good introduction should stick to the cartoon or try Denis Brian's fine biography, Einstein: A Life (LJ 4/15/96).ÄAmy Brunvand, Univ. of Utah, Marriott Lib., Salt Lake City (c) Copyright 2010. Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.



Chapter One Einstein as a Youth Einstein is considered to be one of the greatest scientists that ever lived. He was so famous by the time he came to America that two Europeans, on a bet, sent him a letter addressed "Dr. Albert Einstein, America," and it got to him at Princeton, N.J., with only the usual delay. For a while after he graduated, however, his future looked anything but bright. He expected to get a job as an assistant to one of his professors, but was turned down by them all. For months he sent out applications to nearby universities but no one was interested. He finally got a job as a tutor, teaching one student, but was fired after only a few weeks. He was engaged to be married but his mother hated his fiancée so much he dared not offend her and delayed the marriage. Finally he got a position at the patent office in Bern. He was overjoyed but within months his father died of a heart attack and he was devastated.     Despite his setbacks he continued to work on several important problems in physics and a few years later in 1905 he published five of the most important papers the world has ever seen. Einstein was born in Ulm, Germany, on March 14, 1879, but his family moved to Munich when he was only a year old. Although Jewish, he received his early education at a Catholic school. It has frequently been said that he did poorly in school, but this isn't so. He was always at the top of the class in mathematics and physical science, and although he had little interest in most other subjects and spent little time on them, he did reasonably well in them. His Uncle Jacob instilled an early interest in mathematics and a university student, Max Talmud, who dined with the family once a week, encouraged him and brought him books on math and physics.     Einstein entered the Luitpold gymnasium in 1889, the equivalent of our high school, but he soon resented the discipline and militarism of the school. One of the few highlights of this period was a geometry book that came into his hands when he was in his third year. It had a tremendous effect on him; he worked every problem in the book months before it was covered in class. With the help of Max Talmud he continued studying higher mathematics, and eventually even began studying calculus on his own.     In the early 1890s his father, Hermann, who was in a partnership with his brother Jacob, went bankrupt and decided to move to Milan, Italy, to set up a new business. Einstein was in his third year of gymnasium, and his parents decided to leave him in Munich to complete his education. He also had a military obligation to fulfill when he graduated. Left in a boarding house with a stranger, he was forlorn and lonely.     For weeks he brooded about his situation, then he began scheming as his hatred for the school increased. The only teacher he liked was his math teacher, and in return most of his teachers had a negative opinion of him, not because he was a poor student, but because he was rebellious and moody. He finally went to his doctor, who was a friend of the family, and explained the situation to him. He asked the doctor to write a letter saying he was on the verge of a nervous breakdown and needed the climate of Northern Italy to recover (this is, of course, where his parents were). The doctor reluctantly agreed. Einstein also got a letter from his math teacher stating that his mathematical development was equal to that of a gymnasium graduate. Ironically, as he was getting ready to leave, his homeroom teacher, who was also his Greek teacher, called him in and told him he was a distraction in the classroom, and it was best he leave. The same teacher had told his father earlier that he "would never amount to anything."     Days later Einstein was on the train to Milan. He hadn't told his parents he was coming and was worried about their reaction. As expected they were surprised to see him, and disappointed that he had dropped out of school. To placate them he promised to take the entrance exams at the Polytechnic in Zurich the following autumn. Graduation from a high school was not necessary if you passed these exams. But when his mother inquired, she found that the minimum age for taking the exams was eighteen; Einstein was only fifteen, and would only be sixteen when they were given. With the help of a friend in Zurich, Einstein's mother made an appointment with one of the councilors at the Polytechnic and managed to convince him to let Einstein take the exams.     Over the next few months Einstein studied for the exams, but they would cover most high school subjects and Einstein hated studying botany, zoology, French, history, and so on. Despite reprimands from his mother he spent most of his time studying math and physics, subjects in which he had already demonstrated great strength. His study of physics, in fact, extended well beyond the usual high school curriculum. He was particularly interested in the relation between electric and magnetic fields, and was fascinated by electromagnetic waves, the waves that are all around us in the form of radio and TV waves. They span a spectrum from very long radio waves all the way to extremely short x and gamma rays, with ordinary light in between.     The discovery that light and other electromagnetic radiations were waves posed a dilemma to scientists in the mid-1800s. Waves required a medium of some sort to propagate them. If you threw a stone into a lake a wave moved out from the position where it struck the water, but if you took away the water (the lake) there would be no wave. Waves obviously require a propagating medium so scientists invented one. They called it the ether; it was a strange substance that permeated the entire universe, strange because it was invisible, had no taste or smell, and yet it had to be rigid enough to propagate waves. Furthermore, there seemed to be no way of getting rid of it. If you evacuated a bell jar (in other words, you took all the air out of it), light would still pass through it; therefore the ether was still there.     The concept was so strange that many people found it hard to accept, but there seemed to be no way around it. How could light--a wave--propagate if there wasn't a propagating medium? Einstein was only fifteen when he began thinking about the problem. He would eventually grow to dislike the idea of an ether, but in 1895 he was still intrigued with it. He wrote a five page essay on the subject expressing his opinions, and sent it to his Uncle Caesar in Stuttgart. In the essay he proposed an experiment to determine if electricity, magnetism, and the ether were connected. Caesar was so impressed he wrote Einstein's mother telling her that he was sure Einstein had a great future ahead of him.     It was about this time that Einstein began to consider what it would be like to ride a light beam through space. He tried to visualize what things would look like from the beam. It was obvious that a clock sitting on the beam with him would run as usual, but for someone looking at the clock from Earth no time would appear to pass. The hand of the clock would always be in the same position. The question continued to haunt him for years (see figure 1.2).     In the fall of 1895 Einstein headed for Zurich to take the entrance exams at the Polytechnic. He was well-prepared in math and physics but unsure of himself in most other subjects, and as expected he did extremely well in math and physics and poorly in most other subjects. Overall his grades were not good enough for entrance to the Polytechnic, but officials were so impressed with his math and physics grades that they encouraged him to complete his last year of high school at one of the nearby towns and enter the following year. He would not have to retake the exam. The professor who marked the physics section of the exam was so impressed that he invited Einstein to audit his lectures. Einstein had to decline because he would not be staying in Zurich.     A school in Aarau, a small town about twenty-five miles from Zurich, was selected. Einstein stayed with the Wintelers; Josh Winteler was one of the teachers at the school. Einstein's fear that the school might be like the one he had hated so much in Munich was soon quelled. He found it was much more open and less concerned with discipline. Moreover, with the Winteler family, he could speak his mind. He soon looked upon them as his second family, and for a while he was romantically involved with one of the Winteler girls, Marie. Einstein did much better at this school, and got along well with the teachers. Just prior to graduation he was selected to go on a field trip to one of the mountains in Switzerland, a fateful trip in which he almost fell to his death.     Einstein graduated that summer and the following fall he went to the Polytechnic in Zurich. Because of his hatred of Germany he had renounced his German citizenship and was now stateless. He remained stateless for the next four years until he became a Swiss citizen. The course he signed up for would allow him to teach math and physics at the high school level. There were five people in his class--three majoring in math and two in physics. One of the math majors, Marcel Grossman, became a close friend and the other physics major, Mileva Maric, later became his wife. It might be thought that someone who would eventually change the world of science so dramatically would immediately be at the top of his class at the Polytechnic. After all, he only had to take mathematics and physics now, without the distraction of other subjects that he had no interest in. But again there were problems, which for the most part could be traced to his rejection of authority, his reluctance to accept anything without proving it for himself, and his wide-ranging interests. While he was fascinated with the discoveries being made in physics, he was easily bored by routine classwork. His interests extended beyond the curriculum, and he spent most of his time studying on his own; as a consequence he skipped many classes. In addition, he enjoyed working in the laboratory and spent more time in it than was required. For most this would have been a risky course to take, but his friend Marcel Grossman took excellent notes, and he loaned them to Einstein regularly. (His notes were so good, that they are still on display at the university.) It was these notes that enabled Einstein to pass.     With his cocky, know-it-all attitude, Einstein was not a favorite among his teachers. His physics teacher, Heinrich Weber, the one who invited him to audit his lectures after he failed the entrance exams, was now beginning to dislike him, and his math teacher, Herman Minkowski, called him a "lazy dog."     Luckily for Einstein there were only two exams that had to be passed: the intermediates, taken after the second year, and the finals, taken at the end of the fourth year. Einstein's capabilities were evident in the intermediates. Despite skipping many classes, with some quick cramming he placed at the top of his class. He was slightly embarrassed that he had beaten Grossman after borrowing his notes.     Einstein's neglect of his classes wasn't a result of disinterest or laziness. During most of his college years his mind was whirling with activity. He was studying books on his own by all the top scientists of the day: Hermann von Helmholtz, Ludwig Boltzmann, Gustav Kirchhoff, Ernst Mach, and James Maxwell. He was particularly impressed with Maxwell's electromagnetic theory. To his dismay Weber did not cover the theory in class; when Einstein asked him why, Weber told him he did not feel it was part of the accepted curriculum. Einstein never forgave him.     During this time Einstein's interest in the ether never wavered, and when he was in his fourth year he thought up an experiment that would allow it to be tested through the use of small mirrors and thermocouples (devices for measuring temperature). He went to his teacher, Weber, asking if he could perform the experiment, but Weber turned him down, telling him it would be a waste of time. Interestingly, the experiment was similar (but much less sophisticated) to one performed earlier by Michelson and Morley. Weber also forced Einstein to rewrite his senior thesis on regulation paper just before the finals, denying him valuable study time.     Einstein studied with Mileva for the finals, again using Grossman's notes extensively. This time, however, he didn't place at the top of his class. In fact, all three mathematicians beat him. He was fourth, beating only Mileva, who failed. His average was 4.91 out of 6; Mileva got 4.0. Exams ... Ugh! Comment by Einstein on his final exams at the Swiss Polytechnic in Zurich: "For the exams, one had to stuff oneself with all this rubbish, whether one wanted to or not. This conclusion had such a negative effect on me that after my finals, the consideration of any scientific problem was distasteful for me for a whole year."     Einstein, now a graduate of the Polytechnic, became engaged to Mileva, but when his mother found out she was Serbian, she was enraged. At one point she flung herself on a bed weeping, begging him not to many her. He dared not go against her wishes and postponed the marriage.     After graduation he expected to get a job as an assistant to one of his professors. Assistants were needed in the labs. As the only physicist (besides Mileva, but she had failed), he expected Weber to give him a job, but Weber selected two mechanical engineers with little experience in laboratory physics. He tried most of the other professors, but to no avail. Finally he began applying to other universities, but it didn't help. And as the months passed, he grew more and more depressed. In the meantime he continued to fight with his mother over Mileva; she was still determined to stop the marriage.     Einstein finally went back to Zurich to work on a doctoral thesis and to be with Mileva. He had originally thought about working under Weber, but changed his mind and went to the University of Zurich where he talked to the physics professor, Dr. Alfred Kleiner. Kleiner accepted him as a doctoral student. Interestingly, Einstein submitted what would eventually become his special theory of relativity to Kleiner, but it was rejected because no one at the university could understand it. At this stage it was far from complete, however.     Einstein's interests now turned to capillarity (the rise of water and other fluids in tubes of small diameter). He submitted a paper on the subject to Allenen Der Physiks , the most prestigious physics journal in Europe, and was overjoyed when it was accepted. He was now a published scientist and hoped the publication would help him get a job, but it did little. He continued working on capillarity and soon sent off another paper for publication. It was also accepted.     The one ray of light in his life at this time was a letter from the Immigration Department that he had been accepted for Swiss citizenship. He had been interviewed earlier, and a detective had checked him out. He was happy, but knew he would now have to serve in the Swiss military. Strangely, even though he had rejected his German citizenship to avoid serving in the German military, he now looked forward to serving in the Swiss army. He eagerly reported for the medical exam and was surprised when he was rejected because of flat feet and varicose veins. (They would make it difficult for him to stand the rigors of the extensive marching that would be required.)     He stayed on in Zurich with Mileva, but with no job his money eventually gave out and he had to return to Milan to live with his family. His father's business was now on the verge of bankruptcy so his family could give him little help. Einstein continued sending letters of application from Milan; letters went to the Universities of Göttingen, Stuttgart, Vienna, Bologna, and Pisa. But nobody was interested. He could not understand why he was being so completely ignored; finally he came to the conclusion it had to be Weber. He was using him as a reference and was sure Weber was writing poor letters of reference. He therefore stopped using him.     Soon after reprints of his publication on capillarity were sent to him, he mailed one to Wilhelm Ostwald at Leipzig University. Ostwald was a world expert on capillarity and Einstein was sure he would be impressed, but Ostwald never answered him. His father felt so sorry for him that he decided to write Oswald, hoping it might help. Part of his letter said: I shall start by telling you that my son Albert is 22 years old, that he has studied at the Zurich Polytechnic for 4 years, and that he passed his diploma examinations in mathematics and physics with flying colors last summer. Since then, he has been trying unsuccessfully to obtain a position as an Assistant.... My son feels profoundly unhappy with his present lack of position, and his idea that he has gone off the tracks with his career and is now out of touch gets more and more entrenched every day.     He ended the letter begging him to offer Albert an assistantship, or at least write him a few words of encouragement "so he might recover his joy in living and working."     Nothing came of the letter.     Einstein had reluctantly mentioned his problems to his good friend Marcel Grossman. Grossman talked to his father who, in turn, talked to a good friend, Friedrich Haller, the director of the patent office in Bern. As it turned out a position was opening up in the patent office, and although they usually hired engineers, Einstein's background impressed him. The position would be advertised in the paper soon, and Einstein was encouraged to apply. It would, however, be months before the job became available.     Einstein applied for the position and felt confident he would have a good chance of being hired. But he was so broke that he needed something to see him through the next few months. He finally managed to get a temporary job teaching at the small town of Winterthur as a replacement for one of the teachers who was on military duty, but it lasted only three months. As the job was ending he discovered Mileva was pregnant; there was no way, however, that he could marry her at this point, and she went home to her parents in Yugoslavia to have the baby.      Einstein got another temporary job in Schlaffhaussen, a nearby village, at the institute of a Dr. Neusch. He would be tutoring one student in math. Einstein disliked Neusch from the beginning, finding him overbearing and militaristic. What made things worse was that Einstein had to stay with the Neusches and eat his meals with the family. It was a trying experience and only a matter of time before there was conflict. Einstein finally told him off and was fired on the spot.      It would still be several months before the job in the patent office in Bern would be available--if he got it. He had little money and wasn't sure what to do. He had submitted a doctoral thesis to Kleiner at the University of Zurich, so he went to Zurich to check if it had been accepted. It had not, so he withdrew it, partly to get his doctoral deposit of 220 francs back. He then went to Bern to wait for the job in the patent office.      He knew his money wouldn't last long, so he placed an ad in the Bern paper offering tutoring in math and physics. Within a short time he had two students: Maurice Solovine and Conrad Habicht. He had known Habicht earlier. Einstein had never been one for standing before a group and lecturing, and soon the tutoring ses- sions became discussion sessions with Einstein as group leader. Ein- stein, in fact, preferred to do the discussing as he walked, so many of their sessions took place with the three men on hiking trails. On one occasion they hiked to the peak of a nearby mountain during the night and didn't get back until the following morning.      Their discussion covered many areas: electricity, magnetism, dynamics, thermodynamics and even philosophy and logic. They studied books by Jules-Henri Poincar6, Ernst Mach, Karl Pearson, John Stuart Mill, and others. The money that Einstein brought in from the group, however, was small and he was always on the verge of being broke. The job at the patent office was still weeks away, but Einstein waited patiently and ate sparingly. The meeting continued regularly, and eventually the group began to call themselves the "Olympic Academy." It was a pretentious sounding name, but the three men never took themselves seri- ously; indeed, they loved to play practical jokes on one another. Einstein thoroughly enjoyed the discussions and there's no doubt that they helped develop his ideas. Later in life he said that it was more of an "academy" than some of the ones he was later associ- ated with.      Einstein was finally called in to the patent office for an inter- view by Haller. He was questioned extensively, then a few days later he was hired as Technical Expert Class III with a salary of 3,500 francs a year. It was more money than he had seen in a long time. He wrote Mileva telling her the good news, but mentioned nothing about a wedding. Her baby had been born by now and she was waiting word from him. Within a short time Einstein moved to a better apartment, but he had barely settled in when he re- ceived a letter from home. There was an emergency: his father had had a serious heart attack. Einstein rushed home and within few days his father died. He had always been close to him and was devastated. It took him years to get over it.      His job at the patent office was examining inventions to see if they were worthy of a patent, and that they were not infringing on any other patents. His work schedule left him with a considerable amount of spare time in which he was able to work on his own projects in the evenings. Several problems interested him. One was the problem of absolute motion, in other words, motion that was independent of a reference system. He was particularly interested in its relation to electric and magnetic fields. Newton had postu- lated that absolute motion existed; he couldn't explain why, but he was convinced that space itself could be regarded as a fixed frame of reference. Stars and galaxies would then have motion relative to space. To Newton time was also absolute; in other words, it was the same for all observers throughout the universe. But Einstein was not convinced. Something seemed to be wrong.    Einstein was also interested in proving the existence of atoms. As strange as it might seem, a number of well-known scientists, Ernst Mach and Friedrich Ostwald amongst them, still did not believe in the existence of atoms. Einstein decided it was time to prove once and for all that they existed, but he would have to do it theoretically. It would make a good problem for his doctoral thesis. He was also interested in Max Planck's new concept called "quanta," but it was too controversial for a thesis.     Soon after marrying Mileva, Einstein applied for a teaching position called a "privatdozent" at the University of Bern. It was an unpaid position, with fees being paid by the students, but it was a prerequisite to a professorship. He did not have a doctorate, but had published several papers and hoped they would be sufficient, but they weren't. He was turned down.     The "Olympic Academy" continued to flourish and the discussions helped Einstein see his way through the tangle of new ideas he was considering. His head was now whirling with ideas, and the time was ripe for their development. But alas, Solovine finally got a job teaching at a nearby town and left, and then a few months later Habicht left and the Academy dissolved. Einstein felt the loss; he needed people to talk to about his ideas. Then one day a notice appeared on the bulletin board at the patent office. A position was available. Einstein thought of his close friend Michele Besso, who was an engineer and would be ideal for the job. Furthermore, he had always taken an interest in Einstein's work. He would be an ideal sounding-board, and Einstein was also sure he would be helpful in other ways. He informed Besso of the position, and indeed Besso got it. To Einstein's chagrin he was actually taken on at a higher wage than Einstein.     The two men talked extensively about physics as they walked to and from work, and they frequently got together in the evenings. One of the problems Einstein was now interested in was "the electrodynamics of moving bodies," and it would soon form the basis of his special theory of relativity. His First Honorary Doctorate While still in the patent office in Bern, Einstein received a large envelope in the mail. Opening it he found a letter in fancy, colorful script. Thinking it was an advertisement of no importance he threw it in the wastebasket. Only later did he learn that it was the announcement that he, along with Marie Curie and Wilhelm Ostwald, would be awarded honorary doctorates by Geneva University. When university officials received no reply they asked one of his friends to check. The friend persuaded Einstein to go to Geneva without telling him why. Einstein was quite unprepared and surprised when he found out he was to be awarded an honorary degree. Copyright © 2000 Barry Parker. All rights reserved.

Table of Contents

List of Illustrationsp. 9
Prefacep. 13
1. Einstein As A Youthp. 17
2. The Michelson-Morley Experimentp. 33
The Etherp. 35
Michelsonp. 38
The Michelson-Morley Experimentp. 41
Attempted Explanationsp. 45
Strange Resultsp. 46
3. Special Relativityp. 47
The Foundations of Special Relativityp. 49
Consequences of Einstein's Point of Viewp. 56
Hey! Where Did All the Mass Come From?p. 60
Adding Velocities: Two and Two Equals Four ... Doesn't It?p. 62
Maxwell's Theoryp. 64
Energyp. 64
Waiting for a Reactionp. 65
4. Four-Dimensional Space-Time And Time Travelp. 67
Space-Time Diagramsp. 69
Time Travelp. 77
Time Travel and Science Fictionp. 80
Trip to a Starp. 81
A Professor at Lastp. 83
5. General Relativityp. 85
Inertia and Gravityp. 87
Einstein as a Professorp. 91
Professor in a Strange Landp. 93
Back to Zurichp. 97
The Big Pushp. 98
To Germanyp. 100
6. Gravity and Curved Space-Timep. 103
What is Gravity?p. 104
The Geometry of Space-Timep. 105
Spaces with Varying Curvaturep. 109
Einstein's Gravityp. 110
Tidal Forcesp. 112
Waves of Gravityp. 115
Gravitational Lensesp. 118
The Twin Paradox Revisitedp. 118
7. Testing the Theoryp. 121
Eddington and the 1919 Eclipsep. 122
Hyperspacep. 127
The Precession of Mercury's Orbitp. 128
Clocks in a Gravitational Fieldp. 130
Other Theories and Other Testsp. 134
Tests Using Quasars, Satellites, and Lasersp. 135
Antigravityp. 136
Einstein the Celebrityp. 137
8. Black Holes and Other Exotic Objectsp. 141
Tunnels in Spacep. 144
Oppie and His Croniesp. 146
Properties of a Black Holep. 150
Are There Other Types of Black Holes?p. 151
Extraction of Energyp. 155
Space-Time Diagramsp. 156
Probing a Black Holep. 161
Real Black Holes: The Candidatesp. 163
Mini and Exploding Black Holesp. 167
Journey Into a Black Holep. 169
Time Travel via Wormholesp. 170
Back to Einsteinp. 173
9. To the Ends of the Universep. 175
More Universesp. 177
Freidmannp. 178
The Expanding Universep. 180
The Laughing Giantp. 184
A Competitorp. 185
Radiation from Everywherep. 186
Creationp. 190
The Forces of Naturep. 197
Problems of the Big Bangp. 199
A Lumpy Universep. 200
Inflation Theoryp. 202
Fate of the Universep. 203
Einstein and Cosmologyp. 205
10. Searching for the Elusivep. 207
Working in the Darkp. 208
Einstein Throws in His Hatp. 212
What Was the Problem?p. 215
Final Realizationp. 216
He's Got GUTsp. 218
Stringing Alongp. 220
The Futurep. 223
11. Quantum Quandaryp. 225
Uncertainty and Realityp. 230
The EPR Paradoxp. 233
Schrodinger's Catp. 235
Bell's Inequalityp. 237
Conclusionsp. 239
12. Epiloguep. 241
Notesp. 247
Glossaryp. 257
Bibliographyp. 269
Indexp. 275