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A rising star in theoretical physics offers his awesome vision of our universe and beyond, all beginning with a simple question: Why does time move forward? Time moves forward, not backward, everyone knows you can’t unscramble an egg. In the hands of one of today’s hottest young physicists, that simple fact of breakfast becomes a doorway to understanding the Big Bang, the A rising star in theoretical physics offers his awesome vision of our universe and beyond, all beginning with a simple question: Why does time move forward? Time moves forward, not backward, everyone knows you can’t unscramble an egg. In the hands of one of today’s hottest young physicists, that simple fact of breakfast becomes a doorway to understanding the Big Bang, the universe, and other universes, too. In From Eternity to Here, Sean Carroll argues that the arrow of time, pointing resolutely from the past to the future, owes its existence to conditions before the Big Bang itself, a period modern cosmology of which Einstein never dreamed. Increasingly, though, physicists are going out into realms that make the theory of relativity seem like child’s play. Carroll’s scenario is not only elegant, it’s laid out in the same easy-to- understand language that has made his group blog, Cosmic Variance, the most popular physics blog on the Net. From Eternity to Here uses ideas at the cutting edge of theoretical physics to explore how properties of spacetime before the Big Bang can explain the flow of time we experience in our everyday lives. Carroll suggests that we live in a baby universe, part of a large family of universes in which many of our siblings experience an arrow of time running in the opposite direction. It’s an ambitious, fascinating picture of the universe on an ultra-large scale, one that will captivate fans of popular physics blockbusters like Elegant Universe and A Brief History of Time.


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A rising star in theoretical physics offers his awesome vision of our universe and beyond, all beginning with a simple question: Why does time move forward? Time moves forward, not backward, everyone knows you can’t unscramble an egg. In the hands of one of today’s hottest young physicists, that simple fact of breakfast becomes a doorway to understanding the Big Bang, the A rising star in theoretical physics offers his awesome vision of our universe and beyond, all beginning with a simple question: Why does time move forward? Time moves forward, not backward, everyone knows you can’t unscramble an egg. In the hands of one of today’s hottest young physicists, that simple fact of breakfast becomes a doorway to understanding the Big Bang, the universe, and other universes, too. In From Eternity to Here, Sean Carroll argues that the arrow of time, pointing resolutely from the past to the future, owes its existence to conditions before the Big Bang itself, a period modern cosmology of which Einstein never dreamed. Increasingly, though, physicists are going out into realms that make the theory of relativity seem like child’s play. Carroll’s scenario is not only elegant, it’s laid out in the same easy-to- understand language that has made his group blog, Cosmic Variance, the most popular physics blog on the Net. From Eternity to Here uses ideas at the cutting edge of theoretical physics to explore how properties of spacetime before the Big Bang can explain the flow of time we experience in our everyday lives. Carroll suggests that we live in a baby universe, part of a large family of universes in which many of our siblings experience an arrow of time running in the opposite direction. It’s an ambitious, fascinating picture of the universe on an ultra-large scale, one that will captivate fans of popular physics blockbusters like Elegant Universe and A Brief History of Time.

30 review for From Eternity to Here: The Quest for the Ultimate Theory of Time

  1. 5 out of 5

    Manny

    FREE From Eternity to Here COMPATIBILITY TEST Read through the following dialogue between two people, A and B. Underline all the sentences which you can imagine saying yourself. ____________________________________________ A: What are you thinking? B: Have you ever wondered why the future is different from the past? A: What do you mean, different? B: Well, you can remember the past, but you can't remember the future. Why? A: Like déjà vu? B: No, not déjà vu. Really remembering the future. A: But the futu FREE From Eternity to Here COMPATIBILITY TEST Read through the following dialogue between two people, A and B. Underline all the sentences which you can imagine saying yourself. ____________________________________________ A: What are you thinking? B: Have you ever wondered why the future is different from the past? A: What do you mean, different? B: Well, you can remember the past, but you can't remember the future. Why? A: Like déjà vu? B: No, not déjà vu. Really remembering the future. A: But the future doesn't exist yet. How can you remember something that hasn't happened? B: On the other hand, the only reason you think the past exists is that you can remember it. A: Hmm... maybe! But it would be very confusing to be able to remember the future. You'd have no reason to want to do anything. B: It's not just memory, it's everything! For example, you have photographs of things that have happened in the past, but you can't have a photograph of something that's going to happen in the future. A: But how could you have a photograph of something that's going to happen in the future? B: A camera takes pictures of things that happened in the past. Why couldn't a future-camera take pictures of things that happen in the future? A: Because you can't. It wouldn't work. B: But why not? A: What does that book say? B: It says we can tell the difference between past and future because we're close to the Big Bang. A: What's that got to do with it? B: Well, it's a bit complicated. Imagine that the universe stopped expanding after a while and then collapsed again--- A: Is it going to do that?? B: No, it isn't. But imagine it did. Now would the result look like the Big Bang, only backwards? A: I don't know. B: Well, it wouldn't! That's very interesting, isn't it? A: Let me have a look myself. Hm, hm, hm... so he's got this theory about baby universes that he developed with someone called Jennifer Chen. What's a baby universe? B: Ah, first you have to imagine that our own universe continues for several zillion years--- A: Wait, he dedicated the book to Jennifer! "To Jennifer, for all time". So he developed this weird theory with his girlfriend? That's so romantic! B: It might be a different Jennifer. Let me google it. A: It can't be. B: Oh, it is! His wife's also called Jennifer. Just a coincidence. A: How disappointing! ____________________________________________ Now count the total number of As and Bs in your answers. Mostly As: You are a normal person. Congratulations. Mostly Bs: You spend too much time thinking about things that no one understands. You might enjoy this book. Somewhere in between: Lower your entropy, goddammit. ____________________________________________ And so far we have... Mostly As: notgettingenough, Kat, Warwick, Lynne, Ted, Shayan Mostly Bs: Manny, Tatiana, Riku, Fionnuala, Matt, [Name Redacted], Ariel, Forrest, Shinjini, Saman, Kris, Samadrita, Sarah Lower your entropy, goddammit: Zahro, Ivonne, Stuti, Joe, Jim, Cecily, Kalliope, Rakhi, Eti, Elham, Mike Groot: Robert

  2. 4 out of 5

    Bradley

    This is some very impressive stuff. I've read a lot of nonfiction science books that sometimes had equations but mostly did not, but what I really wanted was a cohesive drive, an arrow to spear right through some of the biggest questions of our time... such as What Is Time. Sean Carroll manages to keep things very sharp between what is perfectly understood and all of the theories that are somewhat understood, and the other Cosmology stuff that's mostly just baffling. :) Any way you look at it, tho This is some very impressive stuff. I've read a lot of nonfiction science books that sometimes had equations but mostly did not, but what I really wanted was a cohesive drive, an arrow to spear right through some of the biggest questions of our time... such as What Is Time. Sean Carroll manages to keep things very sharp between what is perfectly understood and all of the theories that are somewhat understood, and the other Cosmology stuff that's mostly just baffling. :) Any way you look at it, though, this is not a book that gets derailed or goes off into super strange directions. He lays out all the foundations, from the opening definitions of Time and what we think it means, from the average to the rather advanced notions of space-time and curvature, Einstein's energy equation, speed of light, diliation, moving all the way to Black Holes. This is very solid stuff. Plus, we have a very coherent definition of Time as Entropy, showing us just how complicated it can get when time's arrow might just be the illusion that Hawking says it is. I really enjoyed that discussion. Of course, we come up with lots of possibilities and digressions that are always explored in SF, too, but most of these are just bylines, moving quickly by the Grandfather paradox, etc, to get right back on the main track. Yes. We have Equations. :) Fortunately, the author does a very good job about explaining them and even getting deeper into the extra areas that made this rather more interesting for me since I've read many science books and have heard most of this already. I recommend this for anyone interested in Time. :) Not time management. Just Time. :) We do touch rather heavily upon Cosmology by the end, too, which was a blast and a half, getting into many-universes theory and string theory, to name a few. And he makes it clear! :) Seriously. This was some sharp stuff. Very readable. It's not a general overview. You might say it's putting time's arrow right through the heart of a big question and staying on track all the way to the end.

  3. 5 out of 5

    Aerin

    In space, there should be no material difference between left and right, forward and backward, up and down. However, for us there is a substantive difference between up and down because we live in the spatial vicinity of a massive object - the earth - which exerts a gravitational pull on us. And in spacetime, there should be no material difference between past and future. But for us there is a substantive difference because we live in the temporal vicinity of a massive event - the Big Bang - whi In space, there should be no material difference between left and right, forward and backward, up and down. However, for us there is a substantive difference between up and down because we live in the spatial vicinity of a massive object - the earth - which exerts a gravitational pull on us. And in spacetime, there should be no material difference between past and future. But for us there is a substantive difference because we live in the temporal vicinity of a massive event - the Big Bang - which gave rise to the arrow of time. Or so Sean Carroll argues in From Eternity to Here The Quest for the Ultimate Theory of Time. He says that the reason we remember the past and not the future, the reason effects always follow causes and never vice versa, the reason we perceive time always moving in a particular direction, is because of entropy. For whatever reason (physicists collectively shrug their shoulders), the Big Bang was an extremely low-entropy event, and ever since entropy has been increasing and pulling the arrow of time with it. Even if the arrow were to somehow reverse and run time backwards, supposedly we would still remember the low-entropy direction as the "past", and feel we were moving toward the high-entropy "future". Entropy itself is an interesting concept, one that most of us are taught in high school physics class is synonymous with "disorder". But that's not really what it is - entropy measures "the number of microstates corresponding to each macrostate". Basically, the more possible configurations of all the particles within a substance, the higher the entropy, and the more likely the substance is to eventually reach that state. After all, there are many more ways egg molecules can be situated in an omelet than in an unbroken egg, where all the yolk molecules must cluster together, and the albumin, and the shell and so forth. It's just statistics that any given egg is likely to end up in the high-entropy condition. (And another name for these statistics is the Second Law of Thermodynamics.) Since everything is far more likely to be in a high-entropy condition than a low one, it remains a mystery why the universe currently has relatively low entropy, and apparently had even less in the past. Yet that seems to be the case, and so we need the Past Hypothesis: when considering the past, we ignore the statistically-preferred high-entropy condition, and assume that the closer we get in time to the Big Bang, the more the entropy decreases. Why? Well, that's the question the book grapples with, because nobody has the faintest clue. Carroll scoffs at popular concepts like the anthropic principle, irreversible temporal systems, and a symmetrical, entropy-decreasing Big Crunch, as irrelevant or inadequate to explain the mystery. Instead, he's fond of the idea of "baby universes", spawned spontaneously from the maximal-entropy atomic soup of impossibly ancient dead universes. The creation of the baby would have properties similar to the Big Bang - inflation, expansion, low entropy, an arrow of time, and so on. Maybe the reason we observe such crazily low levels of entropy is because our universe is just a toddler. Admittedly, this is a cool idea, but it's not really science. It's not remotely empirical, testable, or falsifiable (which Carroll freely admits). And veering off into crazy metaphysical theories is fun and all, but I mean... we could all be brains in jars, too, or the elaborate fever dream of some minor god. Who knows? I enjoyed this book, though. Its explanation of quantum mechanics was far more lucid and understandable than anything I'd read previously - and it uses cats, but more entertainingly (and humanely) than Schrödinger did. Its speculations on time travel and wormholes and multiple universes gave my inner sci fi geek plenty to chew on. And it introduced me to the concept of Boltzmann brains, which was worth the price of admission in and of itself. But mostly, I just found Carroll's writing to be clear, funny, and affecting. As an example, the following paragraph, which encapsulates everything I consider beautiful and fulfilling about science: We find ourselves, not as a central player in the life of the cosmos, but as a tiny epiphenomenon, flourishing for a brief moment as we ride a wave of increasing entropy from the Big Bang to the quiet emptiness of the future universe. Purpose and meaning are not to be found in the laws of nature, or in the plans of any external agent who made things that way; it is our job to create them. One of those purposes - among many - stems from our urge to explain the world around us the best we can. If our lives are brief and undirected, at least we can take pride in our mutual courage as we struggle to understand things much greater than ourselves. pg. 374

  4. 4 out of 5

    David

    This is a very well-written, and entertaining book on our understanding of the arrow of time. Entropy is a key concept, which deserves (and gets) lots of attention. The second law of thermodynamics states that, in a closed system, entropy can either stay the same or increase--it cannot decrease. Sean Carroll shows why the reversibility of physics at the particle level gives rise to a seeming paradox; if the physics of particles is just as correct with time switched backwards, why can't entropy d This is a very well-written, and entertaining book on our understanding of the arrow of time. Entropy is a key concept, which deserves (and gets) lots of attention. The second law of thermodynamics states that, in a closed system, entropy can either stay the same or increase--it cannot decrease. Sean Carroll shows why the reversibility of physics at the particle level gives rise to a seeming paradox; if the physics of particles is just as correct with time switched backwards, why can't entropy decrease? Carroll discusses this issue at length. I have often wondered, if the universe were to start contracting at some point (for example, if dark energy did not exist, causing inflation to accelerate), wouldn't entropy start decreasing then? Just as I was getting annoyed that the answer wasn't forthcoming, Carroll started addressing this very issue! He explained that a calculation of entropy requires including gravitational fields, especially in the realms of "lumpy" matter. For example, the single supermassive black hole in the center of our galaxy contains more entropy than all of the rest of the universe combined, excluding other black holes! Toward the end of the book, Carroll starts to wander into speculation; he clearly states that his opinion is a minority opinion, but that it is just as well supported as other ideas. The central question that he raises, is this; if the entropy of the universe is still relatively low, but always increases, then at an earlier stage the entropy of the universe must have been much much lower still. So, how did the entropy get that way, so very very low compared to what it would be if the universe were in "equilibrium". It is a very important question in cosmology, but I won't "spoil" your reading by giving away the answer here. Read the book, and discover a truly interesting, but highly speculative explanation of this conundrum.

  5. 5 out of 5

    Kristin

    If I could, I would give 5 stars to the first half of this book and 2 to the second. For the first 500 pages or so (in the iBook version), I was enthralled by Carroll's exceptional ability to lay down the fundamentals of physics and cosmology in clear, straightforward language with simple but highly effective illustrations. This book has by far the best description of general relativity (especially the equivalence principle) for the non-physicist that I have ever encountered. His explanation of If I could, I would give 5 stars to the first half of this book and 2 to the second. For the first 500 pages or so (in the iBook version), I was enthralled by Carroll's exceptional ability to lay down the fundamentals of physics and cosmology in clear, straightforward language with simple but highly effective illustrations. This book has by far the best description of general relativity (especially the equivalence principle) for the non-physicist that I have ever encountered. His explanation of dark matter and vacuum energy is also brilliant--I was all mixed up on those concepts before I read this book but now I feel I have at least some clarity (though in reality I'm probably as confused as ever). I also loved the discussion on black holes, white holes, and Hawking's black hole radiation. The chapter on quantum mechanics, the collapse of the quantum wave function, and the wave function of the universe (is this stuff for real?), and Miss Kitty is also superb. However, the book isn't really meant to be an introduction to the fundamentals of physics and cosmology. It is about the arrow of time (i.e., why we experience time as flowing from past to present to future) and the author's view that it connects not only to the origin of our universe but to a much broader cosmology. We're talking multi-verses, baby universes, and all sorts of other wild visions here. Carroll believes that they key to understanding time, the universe, and everything is...entropy. I would try to summarize entropy here but, quite honestly, I'm now terrified at the thought. Carroll spends about 1/3-2/3 of the book explaining and re-explaining it. It all started with some engineers in the 19th century who were determined to build more effective steam engines. But, in this book, entropy's reach extends far, far, FAR beyond that. And, whether you are convinced by Carroll's application of entropy/thermodynamics will determine your final views on this book. In the end, I wasn't totally convinced. Entropy is a slippery, fuzzy statistical concept, and it seemed to me that Carroll had no trouble defining and re-defining it on a whim to suit his argument. At times, this practice has completely ridiculous and nonsensical consequences (Boltzmann brains, for instance, which the author seems to believe are "out there"). And, I felt that Carroll spent way too much time chasing down dead ends, seemingly for its own sake. I did, however, find the end game--once we finally got there--to be really intriguing and imaginative. It will be interesting to see if his model--of our universe being one of many "baby universes" that bubbled up from an infinite, static, high-entropy background universe--is ever backed up by real data. What is it they like to say in physics? "Shut up and calculate?"

  6. 4 out of 5

    WarpDrive

    This is a very good book about some fundamental modern physics concepts (such as arrow of time, entropy, symmetry, time-reversibility, complexity, theory of information) and their complex inter-relationships. I found that this book has one of the best explanations of entropy for the layman, and the treatment of potentially complex areas such as symmetry, quantum mechanics and relativity, is very good - deeper than in most popular science books. Overall, a very enjoyable read, which would appeal This is a very good book about some fundamental modern physics concepts (such as arrow of time, entropy, symmetry, time-reversibility, complexity, theory of information) and their complex inter-relationships. I found that this book has one of the best explanations of entropy for the layman, and the treatment of potentially complex areas such as symmetry, quantum mechanics and relativity, is very good - deeper than in most popular science books. Overall, a very enjoyable read, which would appeal to a wide audience, from the mathematically challenged (as maths is very minimal), to individuals looking for a deeper treatment of modern physics than what found in most popular science books. Just a couple of areas where I found areas for improvement: - in the treatment of quantum mechanics, the collapse of the wave function is correctly regarded by the author as a potential problem of the so-called "Copenhagen interpretation": this is correct, but there are other interpretations (in particular, the DeBroglie-Bohm theory) that overcome this problem (yes they are non-local, but the author himself actually tends to agree with the non-locality position of this and similar approaches) - so a even brief mention of these alternatives would have made the book much more complete - whilst the concept of symmetry is very nicely illustrated and explained, unfortunately the very important concept of symmetry-breaking is not explained - which I think is baffling in a book which is supposed to deal with time reversibility and the arrow of time. Apart from these minor points, a very enjoyable and rewarding read.

  7. 4 out of 5

    Max

    Carroll offers a provocative explanation for the arrow of time. I found it fascinating, but those without a strong interest in physics may not. Most of the book is spent explaining the basic concepts he uses to make his case. I learned a great deal from these science lessons. In the last few chapters Carroll steps outside the mainstream. He carefully identifies what is speculative. His unconventional ideas true or not were thought provoking. Carroll defines time through its use to label and loca Carroll offers a provocative explanation for the arrow of time. I found it fascinating, but those without a strong interest in physics may not. Most of the book is spent explaining the basic concepts he uses to make his case. I learned a great deal from these science lessons. In the last few chapters Carroll steps outside the mainstream. He carefully identifies what is speculative. His unconventional ideas true or not were thought provoking. Carroll defines time through its use to label and locate events and its perception as something we move through. Unlike space, time has only one direction. Carroll explores this taking care to clarify difficult concepts such as the space of states, microstates, macrostates, time translation invariance, reversibility of the laws of physics and the conservation of information. We get brief but helpful discussions of special relativity, general relativity, quantum mechanics, light cones, black holes, and white holes all of which play into Carroll’s theme. Much of the book is devoted to entropy. The reason we proceed from past to future is entropy, the relentless decrease of order and useful energy. This comes from the second law of thermodynamics. Ultimately the universe will likely stabilize in a high entropy state. Carroll examines Boltzmann’s equation defining entropy and gives us many simple examples to help us understand it. Carroll explains the scientific meaning of entropy as disorder. Scientists do not use disorder in the general sense. That the universe is always going from lower to higher entropy indicates it started in a low entropy state. This is not a law of physics, but an assumption, a boundary condition called the Past Hypothesis. The Past Hypothesis is essential to construct a credible story of the universe. It is often construed to be due to the Big Bang. Perhaps but Carroll has other ideas. Carroll’s point of departure into the speculative part of the book is the question of how the universe began in a low entropy state. Carroll is searching for a credible theory of quantum gravity. He gives an approving nod to string theory admitting it is a work in progress. In one respect Carroll seems to be in line with some popular string theorists. He believes in the multiverse. He posits that universes are created by quantum fluctuations in empty space. These form bubbles that become baby universes that bud off from the universe that formed them, a process without beginning or end. This answers the anthropic principle, the idea that the universe is finely tuned for life, and the problem of first cause. Carroll takes care to craft his solution so that there are fixed space of states with reversible laws of physics and conservation of information. Most important to Carroll is that this is a way the universe could have started with low entropy. Throughout Carroll points out common assumptions that we may forget are assumptions such as the Past Hypothesis. Another is that the universe we can’t see is like the universe we can. There is no reason to believe that. We don’t know what lies outside our small visible slice. Also while there is no evidence of unusual influence from the unobservable universe on our slice, the observable universe is not a closed system. The second Law of thermodynamics only holds true in a closed system. Another common assumption is that the Big Bang model means a singularity was the beginning of time and space. Carroll views the Big Bang model working well as we look backwards until we reach the singularity at which point the laws of general relativity break down. Thus the conditions present in a singularity are unknown. Carroll accepts the theory of inflation because it is consistent with what we believe about the early universe, but as he notes that does not prove it is true. Obviously that can be said of Carroll’s multiverse; just because it can explain conditions such as low entropy doesn’t make it true. As Carroll points out the multiverse is not even a theory since it is not falsifiable. I enjoyed Carroll’s wild ride into the multiverse at the end of the book. It makes just as much sense to me to have multiple universes as it does to have only one, but then I am not a physicist. Carroll writes with enthusiasm and purpose. The basic physics he takes pains to explain he ties nicely together to support his ideas. I learned some worthwhile science, whether or not there is a multiverse. Recommended highly for those who were wondering why we always wake up tomorrow instead of yesterday.

  8. 4 out of 5

    D

    A fascinating course in physics: from Newton and statistical mechanics to special and general relativity and, of course, quantum mechanics, black holes evaporating and the kitchen sink. The author is a master in explaining things intuitively, there's hardly an equation in sight. Especially quantum mechanics is presented in such a way that you 'grok' it without noticing. He makes a strong case that time points to states with more entropy and then comes up with a sketch of a theory that ingeniousl A fascinating course in physics: from Newton and statistical mechanics to special and general relativity and, of course, quantum mechanics, black holes evaporating and the kitchen sink. The author is a master in explaining things intuitively, there's hardly an equation in sight. Especially quantum mechanics is presented in such a way that you 'grok' it without noticing. He makes a strong case that time points to states with more entropy and then comes up with a sketch of a theory that ingeniously combines things to end up with the appearance of low entropy baby verses, each expanding (and increasing in entropy) like our own. Recommended.

  9. 4 out of 5

    Marc

    I’ll be honest: this was a tough job. Sean Carroll really does his best to explain the basic issues of theoretical physics in a comprehensible and pleasant way. Certainly in the beginning he uses a lot of humour, nice literary references and a very patient style to successfully present the ins and outs of classical mechanics (from Newton to Einstein) and quantum mechanics (lots of cats involved). But somewhere halfway through, he starts with what is the logical main part when it comes to time as I’ll be honest: this was a tough job. Sean Carroll really does his best to explain the basic issues of theoretical physics in a comprehensible and pleasant way. Certainly in the beginning he uses a lot of humour, nice literary references and a very patient style to successfully present the ins and outs of classical mechanics (from Newton to Einstein) and quantum mechanics (lots of cats involved). But somewhere halfway through, he starts with what is the logical main part when it comes to time as a physical phenomenon: entropy. And from then on this book slowly becomes a difficult read. From as many as 20-something different perspectives, Carroll tries to answer the question why that entropy exists, how it defines the one-directional arrow of time, and why in our universe it runs from past to future (yep, apparently that is not an obvious question). The answer to that question seems to come down to the initial state of our universe, namely in low entropy. But why was it actually that low back then? From a logical point of view this seems to make no sense. To explain this Carroll jumps from one scenario and theory to another, and every time new issues pop up that make the proposed hypotheses unlikely. It has been cited in some reviews: this book looks like an infinite set of Russian dolls placed one inside another. But in the end Carroll has to conclude: we know too little (especially on quantum gravity) to give a definite answer on this time- and entropy question. But then, Carroll ventures into his own hypothesis (he calls it a prediction, not a theory), which is inspired by the multiversum theory (charming little baby universes are part of it). He admits that this is all very speculative, but he also defends that approach, because to him that is simply the way in which science advances. This was a very interesting book, which ultimately didn't provide a satisfactory answer to the question why time exists as it exists. But it does provide an honest insight into how theoretical science works, although at the cost of a mind boggling reading experience. (2.5 stars)

  10. 5 out of 5

    Mohamed al-Jamri

    This book asks and attempts to solve several important questions such as what is time? Why is there an arrow of time? Was there time before the Big Bang? Why did our part of the universe start in a low entropy state? Is time eternal? Is time travel possible? The author explains several cosmological and physical stuff such as the Big Bang, the Steady State model, special and general relativity. He does so using easy to understand language. However as I finished the first third, the book started to This book asks and attempts to solve several important questions such as what is time? Why is there an arrow of time? Was there time before the Big Bang? Why did our part of the universe start in a low entropy state? Is time eternal? Is time travel possible? The author explains several cosmological and physical stuff such as the Big Bang, the Steady State model, special and general relativity. He does so using easy to understand language. However as I finished the first third, the book started to become hard to follow and I eventually stopped reading by the middle of it.

  11. 5 out of 5

    Merilee

    OK, I cry uncle! I've read 373 out of 470 pages and I am lost. Life's too short. It's not Sean Carroll's fault...I just cannot conceive of multiverses and quantum gravity... OK, I cry uncle! I've read 373 out of 470 pages and I am lost. Life's too short. It's not Sean Carroll's fault...I just cannot conceive of multiverses and quantum gravity...

  12. 5 out of 5

    Hamid

    Figures such as Galileo, Newton, and Einstein are celebrated for proposing laws of physics that hadn’t previously been appreciated. But their accomplishments also share a common theme: They illuminate the universality of Nature. What happens here happens everywhere. Galileo showed that the heavens were messy and ever changing, just like conditions here on Earth; Newton understood that the same laws of gravity that accounted for falling apples could explain the motions of the planets; and Einstei Figures such as Galileo, Newton, and Einstein are celebrated for proposing laws of physics that hadn’t previously been appreciated. But their accomplishments also share a common theme: They illuminate the universality of Nature. What happens here happens everywhere. Galileo showed that the heavens were messy and ever changing, just like conditions here on Earth; Newton understood that the same laws of gravity that accounted for falling apples could explain the motions of the planets; and Einstein realized that space and time were different aspects of a single unified spacetime, and that the curvature of spacetime underlies the dynamics of the Solar System and the birth of the universe. Likewise, the rules governing entropy and time are common to our everyday lives and to the farthest stretches of the multiverse. We don’t yet know all the answers, but we’re on the threshold of making progress on some big questions. Over the course of this book, Sean Carroll investigates what we know about how time works, both in the smooth deterministic context of relativity and spacetime, and in the messy probabilistic world of statistical mechanics. He finally arrives at cosmology, and explores how our best theories of the universe fall embarrassingly short when confronted with the universe’s most obvious feature: the difference in entropy between early times and late times. Understanding a deeply puzzling feature of the natural world is a process that can go through many stages—we may be utterly clueless, we may understand how to state the problem but not have any good ideas about the answer, we may have several reasonable answers at our disposal but not know which (if any) are right, or we may have it all figured out. The arrow of time falls in between the second and third of these options—we can state the problem very clearly but have only a few vague ideas of what the answer might be. In such a situation, it’s appropriate to dwell on understanding the problem, and not become too wedded to any of the prospective solutions. A century from now, most everything Carroll covers in the first three parts of this book should remain standing. Relativity is on firm ground, as is quantum mechanics, and the framework of statistical mechanics. We are even confident in our understanding of the basic evolution of the universe, at least from a minute or so after the Big Bang up to today. But our current ideas about quantum gravity, the multiverse, and what happened at the Big Bang are still very speculative. They may grow into a robust understanding, but many of them may be completely abandoned. At this point it’s more important to understand the map of the territory than to squabble over what is the best route to take through it.

  13. 4 out of 5

    Sabin

    Very, very impressed with the author’s treatment of his subject material. The book is about time. Not about what we do with our time, not about how to manage our time more efficiently, not even about the history of timekeeping, time-travel, or other things that we can do in time and with time. Ok, it is a bit about each of these subjects, but it is essentially about why we have this concept. Why do we perceive time in the way we do and why is time such a difficult concept to grasp. Well it turns Very, very impressed with the author’s treatment of his subject material. The book is about time. Not about what we do with our time, not about how to manage our time more efficiently, not even about the history of timekeeping, time-travel, or other things that we can do in time and with time. Ok, it is a bit about each of these subjects, but it is essentially about why we have this concept. Why do we perceive time in the way we do and why is time such a difficult concept to grasp. Well it turns out that according to the reversible laws of physics in effect around us, time is just a construct by convention: it helps us order events, measure the duration between them and there’s also the fact that we see time as something which flows past us. But just like Terry Pratchett’s “atoms of justice” or “molecules of mercy” there is no fundamental particle of time. The physical process which makes us imagine time is the decay of useful energy, or the increase of entropy. It quite straightforward actually, you notice it as you age: you get weaker, internal organs perform worse, there’s an increasing chance that something will fail, and so on. So the evolution from a low-entropy state towards a higher entropy state is the direction of the arrow of time. And now comes the interesting question. “Why?” Why should there be an arrow of time, a preferred direction, from a low-entropy past to a high-entropy future. Caroll states from the outset that we don’t actually know the answer, but that there are some things we do know. And Caroll hopes they can help point us in the right direction. Instead of an answer to that question, what we get in this book is a very thorough exploration of the concept of entropy in thermodynamics, information theory, black hole cosmology and how it ties together with quantum mechanics. This is not another way to look at the world around us, but a way to challenge the reader to think seriously about an issue with almost no practical implications to our day to day life. The nature of time is right there, on the same level with the beginning of life, consciousness and the nature of reality: we could function very well without knowing any of the details. But by thinking about such issues, a person sees oneself as part of a privileged group, the human species, and their personal existence as a chance event in the great scheme of things. To me it feels like a kind of spiritual liberation. A book of non-fiction always runs the risk of requiring too much specialised knowledge from the reader to properly understand the arguments therein, but, on the other extreme, it can get really dull if it spends too much time on basic information. The middle ground is hard to find and it depends heavily on the reader’s familiarity with the topic. For my part, this book was almost perfect. It filled a lot of holes in my sketchy understanding of entropy and showed me how to think about relativity past its basic implications, but the quantum mechanics part was a bit sketchy. I could follow his arguments, but I was left hungry for more information. Caroll discusses the concept of entropy in depth because it is central to his theory, then gives a whirlwind tour of the main statements in special and general relativity, and also of the most popular interpretations of quantum mechanics. He concludes that the nature of time is still an open issue, without much hope of being solved with our current understanding of the physical laws of the universe, at least until quantum gravity is finally integrated into a unified system of laws. It seems that since we get different configurations of matter when we account for entropy at first without and then with gravity, we will need to understand what happens inside of black holes and on the other side of their event horizon, where quantum gravity becomes important. Since 2010, when Caroll wrote the book, we have made a few more discoveries concerning the nature of gravity, but from what I can gather there is still no definitive theory to integrate the theory of gravity from general relativity with quantum physics. So the answer may still lie out there. I guess one person’s enjoyment of a science book comes down to how much they can actually follow the author’s line of reasoning and understand the author’s conclusions. So for light reading or an introduction and background information you could do worse than read something by James Gleick, but if you feel ready to go to the next level I definitely recommend Caroll. It is demanding, frustrating at times, but well worth the time invested, and has a great bibliography, with suggested reading material both for the specialist and for the reader of popular non-fiction.

  14. 4 out of 5

    Todd Martin

    Science and journalism are two very different disciplines and require a different set of skill sets. Those with skill in one area may or may not have talent in the other. I’m not sure about Sean Carroll’s skills as a scientist, but I have little praise for his talents as a writer. Carroll seems incapable of explaining things clearly. He attempts to illustrate points throughout the book with convoluted examples that appear to be intended to confuse rather than illuminate. He even manages to make v Science and journalism are two very different disciplines and require a different set of skill sets. Those with skill in one area may or may not have talent in the other. I’m not sure about Sean Carroll’s skills as a scientist, but I have little praise for his talents as a writer. Carroll seems incapable of explaining things clearly. He attempts to illustrate points throughout the book with convoluted examples that appear to be intended to confuse rather than illuminate. He even manages to make very simple topics (ice cooling water in a glass, or the uncertainty principle for example) a confusing, over-complicated muddle. Couple the above with a dry, meandering writing style that goes on for close to 500 pages and you are left with a reading experience that can best be described as pure drudgery. In the end, those that already understand the concepts covered will be able to follow Carroll’s tortuous examples, but are unlikely to learn anything new. Those not familiar with the subject matter will probably not be able to follow Carroll’s examples, and are also unlikely to learn anything new. ‘Time’ is therefore better spent elsewhere (let me suggest Brian Greene’s “Fabric of the Cosmos”). So what is the ‘ultimate theory of time’? Time is an inherent property of the universe, it goes forwards and not backwards because entropy would decrease if it did (a violation of the 2nd law of thermodynamics). That’s it.

  15. 5 out of 5

    Tony Heyl

    Time is both a simple and yet complicated scientific question. I looked up books about time after seeing one of the Through the Wormhole shows on Science Channel. This is actually a really well put together book. Most of the book is about entropy and the evolution of the universe, so it makes sense that the content itself goes from the very simple to the very complicated, bring you along the way without making you feel like an idiot. The equations and explanations are also done in a way to reall Time is both a simple and yet complicated scientific question. I looked up books about time after seeing one of the Through the Wormhole shows on Science Channel. This is actually a really well put together book. Most of the book is about entropy and the evolution of the universe, so it makes sense that the content itself goes from the very simple to the very complicated, bring you along the way without making you feel like an idiot. The equations and explanations are also done in a way to really tease out how they came to be formulated so that you understand the timeline of understanding time and can put things into context. The way that charts and examples are done is good too because it's not like you have to move to the next page to understand what the text is saying. By the end of the book, not only did I have a much better picture of time, but also of how a multiverse would work, and it really does make sense. Not the best science book I've read because it is complex at times, but I definitely think it is quality.

  16. 5 out of 5

    Sean

    In the realm of popular physics books, this one is a three-legged mule. It doesn't even have much to say about time, aside from an unbelievably long-winded explanation of entropy. The writing is simplistic in the extreme, yet manages to obscure more than it explains. Carroll obviously wishes he was Brian Greene. He is not. Had to skim the second half of it. In the realm of popular physics books, this one is a three-legged mule. It doesn't even have much to say about time, aside from an unbelievably long-winded explanation of entropy. The writing is simplistic in the extreme, yet manages to obscure more than it explains. Carroll obviously wishes he was Brian Greene. He is not. Had to skim the second half of it.

  17. 4 out of 5

    Nicholas

    Simply the best popular physics book I've ever read. Carroll is amazingly lucid, practical and totally excited about the subject while being conscious of the problems inherent in understanding something that is so fundamental to our existence that we take it for granted: time. What is time? Does it exist naturally, or is it emergent from some other property of the universe? These are the grand questions that drive From Eternity to Here. In fact, the questions are so grand, and so monumental, Car Simply the best popular physics book I've ever read. Carroll is amazingly lucid, practical and totally excited about the subject while being conscious of the problems inherent in understanding something that is so fundamental to our existence that we take it for granted: time. What is time? Does it exist naturally, or is it emergent from some other property of the universe? These are the grand questions that drive From Eternity to Here. In fact, the questions are so grand, and so monumental, Carroll can't help but comment on the scope of modern physics from classical mechanics and relativity to the absurd realities of quantum mechanics. Within From Eternity the lay reader will find a candid and clear discussion of pretty much anything physics related a non-specialist would want to know (and perhaps a few things you didn't). The book is divided into roughly four parts - each dealing with an aspect that explains several key features about time. Of primary focus to Carroll is the arrow of time - a fundamental asymmetry in the flow of time. How is it that we can remember the past, but not the future? It sounds like a nonsensical question at first glance, but when you really think about it, there is no logical reason for why it should be so. The first part of the book attempts to nail down what we even mean by time, and to elucidate some of its properties so that we can better understand what it is we're looking for when constructing a theory of time. Next, Carroll takes us on a whirlwind tour of Einstein's theories of relativity and the way that they distort our common sense notion of what time is and how it's supposed to function. In particular, Carroll emphasizes that subjective nature of time, not in the figurative sense we're all used to (This class feels like it's taking forever!), but in a very literal sense through the exploration of light cones and the time bending effects of black holes. Perhaps the most interesting part of the book follows thereafter. Carroll ties the evolution of time and its direction to the laws of thermodynamics, in particular to statistical mechanic descriptions of the second law: entropy always tends to increase. Here we see asymmetry manifest and perhaps the first clue as to why we perceive time "flowing" in a single direction, or even existing at all. The tendency of any closed system is to always be more and more entropic (here we can insert the word disorganized, but very carefully). In common parlance, any system tends toward the most likely state we should find it in - mostly equilibrium. Think of a box of gas that initially has all of the gas restricted to one side in its initial condition. If we watched such a box over time, what would we find? Most likely, we'd find that in the future, the gas would have dispersed until it reached equilibrium throughout the box, at which point it stops evolving. So goes the universe according to Carroll. For some reason that we're not one hundred percent clear on, the universe just after the Big Bang contained very low entropy. Our experience of change and time rests on the natural working of that system toward a more natural high entropy condition. The last section is highly speculative, but exciting to think about. Here Carroll expands upon a number of theories about the evolution of the universe, its origins and its ultimate destination. Admittedly, there is little evidence from any of the proposals, but they're all fantastic to think about. Carroll seems to succeed more than anything in making you feel smaller and more insignificant than you thought possible. This is an impressive feat given the series of substantial widenings in perspective given to us by scientists from Galileo to Hubble. But it's not a bad thing. On the contrary, there's a wonderful sense of order and determinism in the evolution of the universe as presented by Carroll that's mind-blowing to think about. As a reader, you really can't help but be infected by Carroll's own excitement and optimism that science will ultimately unlock even the deepest mysteries of where we came from and where we're going. Probably not for people who have no concept of physics whatsoever, but if you've read any popular physics books by Greene or Kaku, you'll find that Carroll is much more down to earth. The stuff in the latter section tends toward the esoteric, but it's presented clearly and with as much caution as possible. Pick it up. It's worth your while.

  18. 5 out of 5

    Terence

    Unlike my usual practice since joining GoodReads, I very deliberately did not take notes while reading From Eternity to Here. I wanted to enjoy myself with an interesting topic (cosmology) and not be overly concerned with learning anything - the nonfiction analog of the fictional brain candy I read. But this is the post-GoodReads era of my life so am compelled to offer some note to the interested reader. Thus: The problem under discussion here is the "arrow of time" - why, unlike the physical prin Unlike my usual practice since joining GoodReads, I very deliberately did not take notes while reading From Eternity to Here. I wanted to enjoy myself with an interesting topic (cosmology) and not be overly concerned with learning anything - the nonfiction analog of the fictional brain candy I read. But this is the post-GoodReads era of my life so am compelled to offer some note to the interested reader. Thus: The problem under discussion here is the "arrow of time" - why, unlike the physical principles of space, do the principles of time appear irreversible? It turns out we simply don't know. We know enough about quantum mechanics and classical gravity to make reasonable guesses but absent a theory of quantum gravity we're pretty much fumbling around in a very dark room. Carroll has his own favored answer - which has to do with the multiverse, de Sitter spaces, infinite entropy, low-entropy states and baby universes, and preserves the reversibility of time (though not within a particular universe (sorry, "Dr. Who" fans) - but he's honest enough to say it's unverifiable with the present state of knowledge and lays out other promising competitors. I thought Carroll padded the laying out of the problem (and why it is a problem), and he's another author who has a tendency to make cute, folksy, annoying asides but if you're interested in cosmology this is a book worthy of your unrecoverable time. (In an aside - Reading this book brought to mind one of the worst books I've ever read - John Horgan's The End of Science Facing the Limits of Knowledge in the Twilight of the Scientific Age Helix Books, where the author argues that we've pretty much come to the end of scientific advance and are only mopping up a few loose ends here and there. This is one of the few books that truly disgusted me. Most of my one-stars are simply books that I didn't like but this one made me feel intellectually assaulted. In the light of what we're discovering in space, consciousness and genetics (among the sciences that I'm interested in), Horgan's short-sightedness appears especially appalling.)

  19. 5 out of 5

    Nelson

    Not for the faint of heart. This MIT professor is definitely guarding the tower. I made it through about 70% of the book before my brain exploded. I'm still picking up the pieces. Not for the faint of heart. This MIT professor is definitely guarding the tower. I made it through about 70% of the book before my brain exploded. I'm still picking up the pieces.

  20. 5 out of 5

    Alex Zakharov

    Great read, under proper expectations. The central theme is the puzzle of macroscopic irreversibility which we are all intuitively familiar with - eggs don’t spontaneously unbreak from the frying pan and the milk doesn’t unmix from your morning latte. The puzzle is that at the microscopic level the fundamental laws of physics are perfectly reversible, so why does the Second Law of thermodynamics hold in every situation that we know of? More specifically, Carroll seeks the explanation for why the Great read, under proper expectations. The central theme is the puzzle of macroscopic irreversibility which we are all intuitively familiar with - eggs don’t spontaneously unbreak from the frying pan and the milk doesn’t unmix from your morning latte. The puzzle is that at the microscopic level the fundamental laws of physics are perfectly reversible, so why does the Second Law of thermodynamics hold in every situation that we know of? More specifically, Carroll seeks the explanation for why the time flows in one direction only. Frankly, nobody knows the answer, and even in order to ask the question meaningfully Carroll is forced to cover the basics of relativity, gravity, entropy, thermodynamics, evolution of early universe and quantum field theory. This is a lot of ground to cover and the man refuses to use any equations! Sure, intuition is often useful, but “the unreasonable effectiveness of mathematics in the natural sciences” is not accidental and avoiding equations altogether is a disservice to your audience, no matter what your publishers tell you. And so, the chapters are really hit and miss. For example, the overview of special and general relativity were disappointing (Brian Greene’s and Jeffrey Bennett’s pop introductions are better). Similarly, for clear overview of primordial nucleosynthesis, plasma, and recombination epoch I would go with Max Tegmark. Let’s move on to entropy – the subject is notoriously confusing so I won’t hold too much grudge against the author. In fact he covers Boltzmann entropy better than most, but once he moves out of thermodynamic equilibrium into Shannon, Gibbs and free energy the absence of any equations muddies up the “intuitive” explanation. On the plus side there are number of areas where Carroll is fantastic - black hole thermodynamics, Hawkins radiation and microscopic reversibility were all excellent. The various flavors of Boltzmann brain arguments and the havoc they wreak on the inviolability of arrow of time are by themselves worth the price of the book. And in the end Carroll does make a convincing case for the necessity and arbitrariness of the “Past Hypothesis”. In other words, we fully concede that we cannot derive macroscopic irreversibility from the fundamental laws of physics, and we simply must assume low-entropy early universe as the boundary condition. And it is that boundary condition that sets up the directionality of the Second Law and One-way Arrow of Time. The “Past Hypothesis” seems to be the mainstream view today, in a sense that we have to assume it until we find a better explanation. Naturally, there is no dearth of principled suggestions that attempt to avoid the necessity of assumption (e.g. bubble universes, cyclical time, string-theoretic “branes”), but clearly the question is still open. Carroll himself has a speculative theory (the Carrol-Chen model) where there is a background de Sitter space, in equilibrium and without arrow of time. Against this background, quantum fluctuations occasionally give rise to “baby universes” that start out in a low-entropy state and have local arrows of time (backwards or forward!). These baby universes eventually dilute back into the background, resulting in an overall time-symmetric multiverse. Yep, a little crazy, but wait till you get to the next paragraph. The book was published in 2010 and since then there were further developments in the field. I particularly liked the tasty 2014 marriage of quantum computing and spacetime, where perhaps for the first time in history computer scientists contributed to theoretical physics. Yes, I’m referring to the whole ER=EPR conjecture, and the dissolution of the “Firewall Paradox” with the help of computational complexity. In that context Leonard Susskind explicitly relates space to quantum entanglement, and time to the growth of quantum computational complexity. If this plays out then “Past Hypothesis” won’t be necessary, but till then I will leave you with this thought: “Those who think of metaphysics as the most unconstrained or speculative of disciplines are misinformed; compared with cosmology, metaphysics is pedestrian and unimaginative.” —Stephen Toulmin

  21. 5 out of 5

    Simón

    A good friend of mine, who recently got his PhD. in Quantum Physics, bought me this book as a present a couple of weeks ago. He told me it was very good to get a better understanding of the Universe and the role of (the arrow of) time in it. He was right, and I have enjoyed Sean Carroll's From Eternity to Here: The Quest for the Ultimate Theory of Time very much. I have learnt greatly about the origin of the Universe and its potential fate (view spoiler)[as a sad, cooling, ever-expanding, empt A good friend of mine, who recently got his PhD. in Quantum Physics, bought me this book as a present a couple of weeks ago. He told me it was very good to get a better understanding of the Universe and the role of (the arrow of) time in it. He was right, and I have enjoyed Sean Carroll's From Eternity to Here: The Quest for the Ultimate Theory of Time very much. I have learnt greatly about the origin of the Universe and its potential fate (view spoiler)[as a sad, cooling, ever-expanding, emptiness (hide spoiler)] , about time travel and its feasibility, about symmetry in the laws of physics, about the arrow of time, about entropy... There were several things I didn't like, though: the text has a large number of notes. However, in a style decision I can't understand, these notes are all grouped together at the end of the book, instead of being regular footnotes. While some of them were large enough to justify the need for extra space, jumping several hundred pages to find a bibliographical reference was almost like the written version of being Rickroll'ed. The book also gets more difficult to understand as we progress through different theories. While this makes sense, as we cover more and more complex concepts, I think the amount of care put by the writer at the beginning to make this work understandable gets a bit relaxed later on. In any case, I enjoyed a lot reading From Eternity to Here, and it has already allowed me to talk with my friend about some of the things he researches about!

  22. 5 out of 5

    Mishehu

    Brilliant. Challenging. Enormously thought-provoking. A bit repetitive? In places. A model of clarity? For the most part. But come on, low star reviewers. What do you expect from a discursive (i.e., non mathematical) treatment of so complex a topic? The author makes heavy use of metaphor? How the hell else is he to make abstruse and -- let's face it -- oftentimes pretty bizarre ideas accessible to a non-specialist readership? You were bored? Again, my low-star confreres, why the #%^* did you bot Brilliant. Challenging. Enormously thought-provoking. A bit repetitive? In places. A model of clarity? For the most part. But come on, low star reviewers. What do you expect from a discursive (i.e., non mathematical) treatment of so complex a topic? The author makes heavy use of metaphor? How the hell else is he to make abstruse and -- let's face it -- oftentimes pretty bizarre ideas accessible to a non-specialist readership? You were bored? Again, my low-star confreres, why the #%^* did you bother reading past the first chapter? Bottom line: this is a first-rate piece of popular science writing. By the time you've finished reading it you may not fully understand what time is or why it points in the direction it does, but you'll understand well why cosmologists pose these questions in the first place and where answers to them may one day lie. My sincere thanks to you, Dr. Carroll, for taking what must have been considerable time from your own research to put in the immense effort that writing this book must have entailed. I join the ranks of 5-star readers who were completely wowed by the results.

  23. 4 out of 5

    Daniel R.

    This book is a through and frequently tedious exploration for a theory of time. Pay close attention to the word "Quest" in the subtitle. This books poses many questions that don't have answers yet and instead focuses on the various theories that currently exist. The book starts with an introduction to possible definitions of what time is, the role of entropy, and the Second Law of Thermodynamics. With that foundation it dives into microscopic constituents, macroscopic systems, and quantum mechan This book is a through and frequently tedious exploration for a theory of time. Pay close attention to the word "Quest" in the subtitle. This books poses many questions that don't have answers yet and instead focuses on the various theories that currently exist. The book starts with an introduction to possible definitions of what time is, the role of entropy, and the Second Law of Thermodynamics. With that foundation it dives into microscopic constituents, macroscopic systems, and quantum mechanics before finishing off with inflation, the reversibility of time, and multiverses. I found as I went along the tractability became further removed from everyday life and ended up almost entirely in the realm of theoretical physics and dare I say philosophy. If you are interested in understanding the current state of thinking about what time is, the origins of the universe, and similar topics the author's writing is excellent and the copious footnotes helpful. It just felt like it took an eternity to read.

  24. 4 out of 5

    Rupinder

    An honest, fascinating and surprisingly engaging book about the enigmatic concept of time and its relationship with other equally perplexing concepts of Entropy and Big Bang. The best feature of the book was the honest admission by the author of ideas that have been robustly tested and verified, as well as those which are yet to be accepted by scientists. In the process, Mr. Carroll conveys the excitement and uncertainty around the development of new ideas in Science. The book is richly sprinkled An honest, fascinating and surprisingly engaging book about the enigmatic concept of time and its relationship with other equally perplexing concepts of Entropy and Big Bang. The best feature of the book was the honest admission by the author of ideas that have been robustly tested and verified, as well as those which are yet to be accepted by scientists. In the process, Mr. Carroll conveys the excitement and uncertainty around the development of new ideas in Science. The book is richly sprinkled with personal anecdotes, historical curiosities and various missteps as well as intellectual triumphs of scientists. Additionally, the relationship between time and cosmology is richly elucidated, which was kinda surprising to me. I have to admit that I never thought too deeply about the concept of time before reading this book. All in all, a rewarding book about the latest developments in thinking about this crucial concept in Physics.

  25. 4 out of 5

    Matthew

    The writing is just not interesting enough. This is a survey book, not a scientific study, and I guess I have been spoiled by all of the great humor, wit, and presentation that modern science survey writers have brought to bear on this type of work. The material here is not new to me, though, to be sure, some of the concepts I have never fully wrapped my head around. Nevertheless, if I'm going to read a survey book like this I want the material within to be presented in an entertaining manner. The writing is just not interesting enough. This is a survey book, not a scientific study, and I guess I have been spoiled by all of the great humor, wit, and presentation that modern science survey writers have brought to bear on this type of work. The material here is not new to me, though, to be sure, some of the concepts I have never fully wrapped my head around. Nevertheless, if I'm going to read a survey book like this I want the material within to be presented in an entertaining manner.

  26. 5 out of 5

    Lara

    Actually, yeah, I think I'm done with this one--I just can't seem to get interested, even though it's definitely a fascinating topic. I feel like maybe it's bogged down by too many examples or something, and thus I'm finding it really, really tedious. I can see how it might be a great book for folks that haven't really read anything about the basics of physics before, because I do feel like he's explaining things pretty clearly, but I'm not really getting anything out of it, other than annoyed. Actually, yeah, I think I'm done with this one--I just can't seem to get interested, even though it's definitely a fascinating topic. I feel like maybe it's bogged down by too many examples or something, and thus I'm finding it really, really tedious. I can see how it might be a great book for folks that haven't really read anything about the basics of physics before, because I do feel like he's explaining things pretty clearly, but I'm not really getting anything out of it, other than annoyed. I guess I am not exactly known for my patience...

  27. 4 out of 5

    Ramon van Dam

    Very impressive. Carroll isn't afraid to dive into the unknown and speculate wildly, but he makes sure to acknowledge it when that is the case. I have to admit several sections went a bit over my head (even after reading a lot of relatively similar books), but the author kept me hooked with lots of examples and analogies. Highly recommended for everybody that is interested in astrophysics, but it's probably not suited as a first entry into the subject. Very impressive. Carroll isn't afraid to dive into the unknown and speculate wildly, but he makes sure to acknowledge it when that is the case. I have to admit several sections went a bit over my head (even after reading a lot of relatively similar books), but the author kept me hooked with lots of examples and analogies. Highly recommended for everybody that is interested in astrophysics, but it's probably not suited as a first entry into the subject.

  28. 4 out of 5

    Per André

    It started out really interesting and to the point about the essence of time, and how time relates to relativity and quantum mechanics. Gradually, it morphed into a book about the author's favorite topic: Entropy. The book never really recovered. It's well written, but I'm still in search of a great book on time. It started out really interesting and to the point about the essence of time, and how time relates to relativity and quantum mechanics. Gradually, it morphed into a book about the author's favorite topic: Entropy. The book never really recovered. It's well written, but I'm still in search of a great book on time.

  29. 5 out of 5

    Roman Faminou

    This book is extremely good but is definitely not popular science the way I imagine it. It's tough to get through for someone without a background in physics, and I found myself going much slower than with most other books and still not getting everything. Part of me wishes I knew more about the subject before reading as I would have appreciated the information much more. This book is extremely good but is definitely not popular science the way I imagine it. It's tough to get through for someone without a background in physics, and I found myself going much slower than with most other books and still not getting everything. Part of me wishes I knew more about the subject before reading as I would have appreciated the information much more.

  30. 5 out of 5

    William Schram

    From Eternity To Here by Sean Carroll is an excellent book on the nature of time itself. The book is for the layman and is quite well-written, with its focus being on the Arrow of Time and why it exists. Through his musings, we find content on Information Theory, Statistical Thermodynamics and so on. This book touches on a great many subjects in Physics. The book doesn’t have many equations but it does take some understanding of the Second Law of Thermodynamics. That is the law that states that t From Eternity To Here by Sean Carroll is an excellent book on the nature of time itself. The book is for the layman and is quite well-written, with its focus being on the Arrow of Time and why it exists. Through his musings, we find content on Information Theory, Statistical Thermodynamics and so on. This book touches on a great many subjects in Physics. The book doesn’t have many equations but it does take some understanding of the Second Law of Thermodynamics. That is the law that states that things tend toward disorder. While it is possible to unbreak an egg, it is extremely unlikely. Most physical equations don’t have a preferred direction in time. This makes it easy to calculate certain things. However, that is not the same for our experiences of the world as a whole. To see such a phenomenon as the unbreaking of an egg; or cream, sugar, and coffee unmixing into their constituent parts would be akin to watching a movie in reverse. Here’s the crux of the matter, it isn’t forbidden for such things to happen. Like I mentioned before, it is quite unlikely for a floor to hit all the molecules of a broken egg back into place, but that doesn’t make it completely impossible. Using these ideas, we can extrapolate back in time to the Big Bang. Supposedly, the time of the Big Bang was a situation in which the Universe was perfectly ordered and had extremely low entropy. We can infer this since the entropy of the universe tends to increase with time. If the Universe started out at a high entropy state, nothing would happen, and I would not be here to write this review. While the book doesn’t have many equations as I mentioned, the ones that it does contain are pretty famous. Well, to some, I suppose. Einstein’s E=mc squared is almost ubiquitous, but while his Field Equation for General Relativity is famous to a select few, I can’t imagine many people recognizing that one. As it does cover all these things, relativity comes into play; with light cones, Spacetime, Black Holes, and all of that good stuff. Throughout the book, we find references to such luminaries as Ludwig Boltzmann, Sadi Carnot, Rudolf Clausius, James Clerk Maxwell, and others. Along with the founders of Thermodynamics and other disciplines, we also follow some more modern scientists. This book is really good, as I might have mentioned before. If you can find it, I feel it is worth a look.

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