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Time travel is certainly one of the most fun topics in physics, but it has a serious side as well. I have received calls from people who want to know about recent developments in time travel because they wish to return to the past to rescue a loved one who died under tragic circumstances. I treat such calls with great seriousness. I have written this book partly to answer such questions. One reason that time travel is so fascinating is that we have such a great desire to do it.
Physicists like me who are investigating time travel are not currently at the point of taking out patents on a time machine. But we are investigating whether building one is possible in principle, under the laws of physics. It’s a high-stakes game played by some of the brightest people in the world: Einstein showed that time travel to the future is possible and started the discussion. Kurt Gödel, Kip Thorne, and Stephen Hawking have each been interested in the question of whether time travel to the past is possible. The answer to that question would both give new insights into how the universe works and possibly some clues as to how it began.
This book is a personal story, not a history of science. Imagine me as your guide, taking you to the summit of Mount Everest. The climb is sometimes challenging, sometimes easy, but I promise that we will ascend by the easiest possible route. It’s a path of ideas I know well, having marked some of the trail myself. Along the way, we will intersect the work of many of my colleagues. I have mentioned many of them to give you a fair idea of the other trailblazers of this terrain. Some contributions are emphasized and others briefly noted, in or out of historical sequence, as they play into telling my story. To those whose work I’ve not mentioned -- though it may be equally important but following a different route up the mountain -- I apologize in advance. We start our journey at base camp: the dream of time travel itself and the pathbreaking science fiction of H. G. Wells.
|1||Dreaming of Time Travel||3|
|2||Time Travel to the Future||33|
|3||Time Travel to the Past||76|
|4||Time Travel and the Beginning of the Universe||131|
|5||Report from the Future||200|
Barnes & Noble.com: Like many people, I'm fascinated by the idea of time travel. You give scenarios where time travel would be possible, but only by super-advanced civilizations, using cosmic strings, for example. If time travel is possible at all, is there some hope of achieving it before reaching such exalted heights?
Richard Gott: Time travel to the future is possible, and we are doing it in a small way even today. Einstein showed that rapidly moving clocks tick more slowly than ones on Earth. If you were to travel to a star 500 light-years away and return at 99.995 percent of the speed of light, you would age only 10 years during the trip -- but you would find Earth 1,000 years older when you returned. Our greatest time traveler so far is cosmonaut Sergei Avdeyev, who orbited the earth for 748 days in 3 space flights, with the result that he is about 1/50th of a second younger than he would have been if he had stayed home. Put another way, he has journeyed about 1/50th of a second into the future, because when he returned he found earth about 1/50th of a second further into the future than he expected. If, in the upcoming century, an astronaut were to go to the planet Mercury and spend 30 years living there before returning home, he would be about 22 seconds younger than if he had stayed on Earth. Clocks on Mercury tick more slowly than those on Earth, both because Mercury orbits the sun at higher speed and because it is deeper in the sun's gravitational field -- which Einstein showed also causes clocks to slow. How far we travel into the future is basically a matter of how much money we are willing to spend on the project. In the 21st century I think we will continue to see time travel to the future, but only in small jumps.
Time travel to the past is more difficult. It is allowed by Einstein's theory of gravity but it requires an extreme twisting of space, as might occur in wormholes or around rapidly contracting cosmic string loops (where you would likely end up trapped inside a black hole). To understand whether you could complete such a time travel journey to the past before being killed, we may need to understand the laws of quantum gravity -- this is one reason the problem is so interesting. Time travel to the past is a project only supercivilizations could attempt. Kip Thorne and his colleagues have proposed a wormhole solution propped open by the quantum vacuum state between electrically charged plates weighing 200 million times as much as the sun, while a cosmic string loop that you could circle to go back a year in time would weigh about half the mass of our galaxy. These are construction projects on a grand scale. Physicists like myself working on this are not yet at the point of taking out patents on time machines, but we are interested in knowing if it is possible in principle under the laws of physics, because that may provide clues to how the universe works -- and even how it began.
B&N.com: Your research is not on human time travel, per se, but on the theory that the universe created itself through a kind of time loop, like a jinn.
RG: Time loops allow unusual phenomena. First, consider your own path through space and time. It is called your world-line. It starts at your birth, snakes through all the events of your life, and ends at your death. If space and time are sufficiently twisted to allow time travel to the past, there may be some particles (called jinn) with circular world-lines, having no beginning and no end. Some famous time-travel science fiction stories have included such jinn. The pocket watch in the movie "Somewhere in Time" is an example. A time traveler in the story receives a watch from an old woman. He takes the watch back in time to give to that same woman when she was young. She saves it her whole life and returns the watch to him when she has become an old woman. The watch has a circular world-line -- it never went anywhere near a watch factory. In a variation on this theme, Robert Heinlein wrote a famous story, "All You Zombies," where a time traveler's convoluted visits to the past (one including a sex-change operation) allowed him to become both his own mother and father! Jinn particles are not just fascinating devices, but must be considered in calculating quantum probabilities in time travel situations.
In trying to understand the origin of the universe, Andrei Linde proposed that universes can give birth to other universes, like branches budding off a tree. This eventually produces an infinite fractal tree with an infinite number of universes. But where did the trunk come from? Li-Xin Li and I have proposed that one of the branches simply loops back in time to become the trunk. This small time loop at the very beginning of the universe allows the universe to be its own mother!
B&N.com: Along with time travel, you also describe many of the new discoveries in physics and cosmology. Is this a particularly exciting time to be working in these fields?
RG: We live, as most people will, in an epoch of high population. Since it is people who make discoveries, it is not surprising to find ourselves living in an epoch in which many exciting discoveries of all sorts are being made. In cosmology, we have seen extraordinary progress in the last century -- from Hubble's discovery in 1929 of the expansion of the universe to Penzias and Wilson's 1965 discovery of the cosmic microwave background radiation left over from the Big Bang itself. Breakthrough theoretical ideas, such as Alan Guth's inflation and Linde's chaotic inflation have led us to a picture of universes spawning universes. Recent measurements of the cosmic microwave background and distant supernovae have been in dramatic accord with such theoretical ideas. Giant surveys (like the Sloan Digital Sky Survey) are allowing us to begin mapping the universe in unprecedented detail, while advances in computers enable us to model the formation and clustering of galaxies to test our theories. Superstring theory offers us the hope of one day finding a "theory of everything," explaining and unifying all the laws of physics. These are all extremely exciting developments.
B&N.com: Is there anything else you'd like to add?
RG: Time travel research is one of the most fun topics in physics, but it has a serious side as well. Time travel was inconceivable in Newton's universe, but Einstein's universe it has become a possibility. Einstein started the discussion by showing that time travel to the future was possible. Kurt Gödel, one of the 20th century's most distinguished mathematicians, found a solution to Einstein's equations of gravity allowing time travel to the past -- a rotating universe. Kip Thorne and his colleagues found a different solution involving wormholes, and I found one involving cosmic strings. Trying to understand whether these solutions can be realized may require us to understand quantum gravity. As Li-Xin Li and I have argued, time travel solutions may even hold the key to how the universe began.
Posted March 9, 2012
Time Travel has been a questioning topic on many storytellers’ and scientists’ minds. Although this concept can seem very complicated, J. Richard Gott uses simple ways of explaining these complex ideas. He uses references such as fictional movies to better portray the possibilities of time travel. He also uses many pictures and graphs to explain the even more intricate parts of time travel.
It may seem impossible, but Gott proves that time travel has already happened, and will continue to become more improved. Gott explains how every astronaut that goes into space, time travels. Using Einstein’s Theory of Relativity, we must have two general assumptions: the speed of light is the fastest speed anything can travel, and the speed of light is the same to all observers. Using this theory we can show that when Astronauts go to space, they travel at extremely high speeds, therefore having time go “slower” for them. Relativity is the beginning of all Time Travel.
While Gott explains the mathematics behind time travel, he also uses fiction novels and movies to describe the possibilities of the future. Movies such as “Bill and Ted’s Excellent Adventure” and “Back to the Future” display how fiction becomes reality. We all like to read fiction novels and watch fiction movies because they are not real, so that we can imagine our own lives outside of the norm. Scientists take these ideas and put research into them to make them real. Many of the inventions today all come from the imaginations of artists we all enjoy. Imaginative ideas, such as an invisibility cloak, are coming ever closer to existence. Scientists in France have invented a device that can warp heat waves, so that they bend heat around an object, and keep the object at a certain temperature. There is only one more step to create the invisibility cloak that no one thought was possible. What we can take from this novel is that imagination is the driving force behind science, for all inventions come from the inspiration of creative artists.
This book creates a fascinating experience for any reader, although more preferably for one who is interested in physics. The book may incorporate complicated physics, including integrals, graphs, and other mathematical queries, but Gott expresses these terms in simple ways, so that the average reader can understand the physics behind time travel. All people should read this book. This book will educate one with fascinating knowledge about the unknown, and what future possibilities await us.
Some other novels related to physics are The Fabric of Reality and Why Toast Lands Jelly Side Down. The Fabric of Reality is a bit more complex book than Time Travel In Einstein’s Universe, as is contains more intense equations that a physicist would know. One without a physics background should not read this book. Why Toast Lands Jelly Side Down on the other hand is much more simple, it only incorporates the most basic physics equations, so it suits any person of any background.
Time Travel In Einstein's Universe is Possible
In Time Travel in Einstein's Universe: The Physical Possibilities of Travel Through Time J. Richard Gott uses Albert Einstein's theories to prove that time travel is possible, and explore the different ways of traveling to the future or past. Throughout the book Gott uses easily understandable diagrams and math to prove how it is possible. The major message of this book is that time travel could possibly be accomplished sometime in the future when the technology has advanced enough. He explains how one could travel backwards in time through wormholes in space or by traveling in warpdrive (moving faster than the speed of light). He also explains how traveling forward in time could be possible using Einstein's theory of relativity, and explores both using various theories. My favorite aspect of this book was the use of diagrams for explanations. The explanations paired with the diagrams and pictures help the reader to understand the more obscure theories. I also enjoyed the movie connections that the author made in the first chapter. He discussed the types of time travel in movies such as "Bill and Ted's Excellent Adventure" and "Back to the Future" and explained why they were or were not possible. However the authors ego hinders a good portion of the book while he proves and praises the theories that he produced. I think that anybody who is interested in time travel or even anybody who likes "Back to the Future" or "Bill and Ted's Excellent Adventure" should read this book. It gives many different methods for traveling through time which he proves using Einstein's theories and theories of other famous scientists while keeping good perspective on reality, and is very well explained making it fairly easy to understand. I would also recommend reading the book "A Brief History of Time" by Stephen Hawking because many of the theories that Gott uses in his book are explained more in depth in Hawking's book.
Overall I give this book four stars because it is very interesting and the concepts are explained adeptly enough for non-physicists to understand.
Posted August 8, 2004
This book is one that you just can't put down. There is obviously no storyline t it but the way it is put together is just perfect. Gott uses modern, everyday scenarios to make sure you fully understand the concept of what he's trying to teach you (i.e. using the 50% and 95% Copernican Argument to predict how long things like Manhatten and the human race will continue to exist.) I would definitely recommend this to anyone who has ever been remotely interested in astrophysics.Was this review helpful? Yes NoThank you for your feedback. Report this reviewThank you, this review has been flagged.
Posted November 13, 2003
This book is spectacular so long as you rip out the last chapter once you remove the book from its box. It wonderfully delves into the time travel concept from a physicist's perspective, showing how General Relativity makes time travel easily acceptable in theory (if not quite so easy in practice). Cosmic strings are a delight to read about. But what is the last chapter doing in there? It basically consists of a poorly reasoned, several-times-debunked statistical method that the author pats himself on the back for way too much. It should have been left out on account of irrelevance alone, not to mention its many flaws and the arrogance with which the author presents it. Gott is correct to suggest the importance of starting space travel sooner and more intensely than we might have otherwise thought necessary, but he needs to lay off a bit on the know-it-all self-admiration with which he praises himself for a statistical method that's weak, wrong, and useless in general.Was this review helpful? Yes NoThank you for your feedback. Report this reviewThank you, this review has been flagged.
Posted January 3, 2010
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