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scott_h_119's review against another edition
4.0
Great book. It is essential to our understanding of the universe that we understand time. this angle, though, "what is time itself?" is rarely addressed in other works on cosmology. The fact that this book tries to fill that gap is absolutely admirable. It gets heady near the end - as books of this kind are wont to do - but finishes strong. I'm glad I stuck with it.
canttalknow_reading's review against another edition
4.0
Heavy but rewarding book on the origin of the universe and why there is an arrow of time.
johndsouza's review against another edition
3.0
Starts out well, but then gets a little too deep for my amateur tastes in the latter half of the book.
zeteticzymurgy's review against another edition
4.0
This book was good, but very dense. I don't think I would have appreciated it without having a pretty hefty background of popular physics book. That said, it was nice to read a book that took a deep dive into topics that usually get glossed over in popular science books. In particular, I learned a lot about both inflation theory and the holographic principle, which were really interesting. I especially appreciated the discussion of the holographic principle, because it seems (after reading the discussion here) that every popular-level discussion of it I've ever consumed is mis- and/or overstating it.
I docked a star because the book ended with a whimper rather than a bang, but I'll admit that's not entirely fair. The book was more of a "call to arms" regarding the problem of the arrow of time, and thus wasn't aiming to provide an answer, but rather explicitly posing the problem in full. Also, I'm sure this will let the book age better than other science books that finish by getting lost in aimless speculation or wetting themselves over the flavor-of-the-month experimental result at the time of publishing. (Carroll basically admits consciously avoiding this in the postscript.) Nevertheless, I can't deny the book somewhat fizzled out at the end, and that detracted a bit from the reading experience.
I'd recommend this to people who've already consumed a healthy amount of popular physics books (Hawking, Brian Greene, etc), but probably not for folks without that background.
I docked a star because the book ended with a whimper rather than a bang, but I'll admit that's not entirely fair. The book was more of a "call to arms" regarding the problem of the arrow of time, and thus wasn't aiming to provide an answer, but rather explicitly posing the problem in full. Also, I'm sure this will let the book age better than other science books that finish by getting lost in aimless speculation or wetting themselves over the flavor-of-the-month experimental result at the time of publishing. (Carroll basically admits consciously avoiding this in the postscript.) Nevertheless, I can't deny the book somewhat fizzled out at the end, and that detracted a bit from the reading experience.
I'd recommend this to people who've already consumed a healthy amount of popular physics books (Hawking, Brian Greene, etc), but probably not for folks without that background.
missnorth's review against another edition
3.0
This book covers some mind-bending scenarios. My favorite being the idea that the big bang might have happened because entropy sometimes "defies" the second law due to reality's vastness and it's bound to happen eventually. While I loved learning about the latest theories on time, I felt the author took too roundabout a path to get to his points. Sometimes I'd read pages into a theory (like the backwards entropy above) and still not understand whether the theory has been rejected or whether its still on the table. But if you're looking for a good history of a scientific field, this will satisfy your curiosity.
paigemcloughlin's review against another edition
5.0
Damn time does a number on all of us Seanny boy. Old Ted Talk by the author from 11 years ago.
https://www.youtube.com/watch?v=WMaTyg8wR4Y
I am rereading this book again. I have read I think most of Carroll's popular books. This one is one of my favorites because it deals with entropy, time's arrow, cosmology, the inflationary big bang, Boltzmann Brains, and multiverses. This is his earliest popular work and I think his best and the most fun. I like his something deeply hidden as well but this book is my fave.
update 10/4/2021 This book covers the big bang, time, and entropy and how all three are inextricably linked in a conundrum of the universe. Entropy is always increasing but why did it start so low at the beginning. If the universe was going to come into being it is astronomically more like to start at near maximum entropy but it didn't the beginning was very special. We wouldn't be here (except as a Boltzmann brain and you don't want to be a Boltzmann brain) if the universe didn't start at shockingly low entropy, Excellent romp through high level physics and cosmology.
Update 10/3/2022 (I still use four digits for the year because I can't accept that we are no longer living in the twentieth century). Anyway early book by Carroll that has all the themes of Carroll's later Career. Time, Entropy, Multiverse, Many-worlds interpretation, Inflationary Cosmology, Boltzmann Brains. People can be damned consistent, can't they?
Anyway, I put detail in the page updates. Have fun.
https://youtu.be/kfffy12uQ7g
https://youtu.be/kii-s2eDZps
https://youtu.be/yKbJ9leUNDE
https://youtu.be/3AMCcYnAsdQ
https://youtu.be/MTFY0H4EZx4
https://youtu.be/sAMlGyaUz4M
https://youtu.be/HxTnqKuNygE
https://youtu.be/mg0hueOyoAw
https://www.youtube.com/watch?v=WMaTyg8wR4Y
I am rereading this book again. I have read I think most of Carroll's popular books. This one is one of my favorites because it deals with entropy, time's arrow, cosmology, the inflationary big bang, Boltzmann Brains, and multiverses. This is his earliest popular work and I think his best and the most fun. I like his something deeply hidden as well but this book is my fave.
update 10/4/2021 This book covers the big bang, time, and entropy and how all three are inextricably linked in a conundrum of the universe. Entropy is always increasing but why did it start so low at the beginning. If the universe was going to come into being it is astronomically more like to start at near maximum entropy but it didn't the beginning was very special. We wouldn't be here (except as a Boltzmann brain and you don't want to be a Boltzmann brain) if the universe didn't start at shockingly low entropy, Excellent romp through high level physics and cosmology.
Update 10/3/2022 (I still use four digits for the year because I can't accept that we are no longer living in the twentieth century). Anyway early book by Carroll that has all the themes of Carroll's later Career. Time, Entropy, Multiverse, Many-worlds interpretation, Inflationary Cosmology, Boltzmann Brains. People can be damned consistent, can't they?
Anyway, I put detail in the page updates. Have fun.
https://youtu.be/kfffy12uQ7g
https://youtu.be/kii-s2eDZps
https://youtu.be/yKbJ9leUNDE
https://youtu.be/3AMCcYnAsdQ
https://youtu.be/MTFY0H4EZx4
https://youtu.be/sAMlGyaUz4M
https://youtu.be/HxTnqKuNygE
https://youtu.be/mg0hueOyoAw
sense_of_history's review against another edition
A fascinating book, about a subject that interests me greatly: why does time exist and why does it always flow in one direction? Of course, we end up with the inevitable second law of thermodynamics and the concept of entropy. Carroll really does his best to explain the consequences of that strange concept, and especially the mysteries that linger around it. But for the time being, science does not succeed in formulating a truly satisfactory answer, and so doesn’t Carroll. See my review in my general account Marc: https://www.goodreads.com/review/show/2938063217?type=review#rating_229494305.
I was somewhat disappointed by the lack of a clear answer to that basic question about time. But nevertheless Carroll in this book introduces a number of lines of thought that stimulated me in my current reading program about time experience and temporality. For example, he refers to an interesting remark in John Pirsigs' cult book [b:Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values|629|Zen and the Art of Motorcycle Maintenance An Inquiry Into Values|Robert M. Pirsig|https://i.gr-assets.com/images/S/compressed.photo.goodreads.com/books/1410136019l/629._SY75_.jpg|175720], namely that the ancient Greeks apparently “saw the future as something that came upon them from behind their backs, with the past receding away before their eyes”. I do not know where Pirsig got this from (Plato/Aristotle?), but it is a view that intrigues because it goes against our intuitive feeling in western modernity that a person always is facing the future and has the past in his back. Interesting to ponder about that one.
Another notion that comes up in this book is our intuitive sense about the past as fixed, unchangeable, as opposed to the future that seems like open to many possibilities. Theoretical physics seriously challenges this view: in quantum physics cause and effect do not appear to be unambiguously linked to each other and - at least in theory - can also occur in reverse order. That uncertainty actually fits in with the post-modern historiography of the last decades, which places a great deal of emphasis on perception and representation. In an extreme version of that current the past seems to be open to infinite variability. I don't agree with that extreme way of looking at the past, but you can't just wipe it off the table: every glance at the past is coloured by the present and the context of the observer, and the 'represented' past can therefore undergo considerable change over time.
The observation that we are living in a 4-dimensional universe, where spatial aspects take on 3 dimensions, but time is limited to only 1, also stimulates the imagination. I understand from Carroll that (in connection with the issue about entropy) scientists still cannot really give a clear explanation for that one time dimension (there are theoretical models that take into account multiple temporal dimensions, but frankly this line of thinking seems very much like pure science fiction). And so we arrive at what may be the best quote that this book contains: "But the question remains: "what is time?" The response from the American physicist John Wheeler is worth remembering: "Time is nature's way of keeping everything from happening at once.” It may seem a very laconic way of representing things (not taking into account the quantum mechanical issues), but this statement certainly is unequivocal.
(rating 2.5 stars)
I was somewhat disappointed by the lack of a clear answer to that basic question about time. But nevertheless Carroll in this book introduces a number of lines of thought that stimulated me in my current reading program about time experience and temporality. For example, he refers to an interesting remark in John Pirsigs' cult book [b:Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values|629|Zen and the Art of Motorcycle Maintenance An Inquiry Into Values|Robert M. Pirsig|https://i.gr-assets.com/images/S/compressed.photo.goodreads.com/books/1410136019l/629._SY75_.jpg|175720], namely that the ancient Greeks apparently “saw the future as something that came upon them from behind their backs, with the past receding away before their eyes”. I do not know where Pirsig got this from (Plato/Aristotle?), but it is a view that intrigues because it goes against our intuitive feeling in western modernity that a person always is facing the future and has the past in his back. Interesting to ponder about that one.
Another notion that comes up in this book is our intuitive sense about the past as fixed, unchangeable, as opposed to the future that seems like open to many possibilities. Theoretical physics seriously challenges this view: in quantum physics cause and effect do not appear to be unambiguously linked to each other and - at least in theory - can also occur in reverse order. That uncertainty actually fits in with the post-modern historiography of the last decades, which places a great deal of emphasis on perception and representation. In an extreme version of that current the past seems to be open to infinite variability. I don't agree with that extreme way of looking at the past, but you can't just wipe it off the table: every glance at the past is coloured by the present and the context of the observer, and the 'represented' past can therefore undergo considerable change over time.
The observation that we are living in a 4-dimensional universe, where spatial aspects take on 3 dimensions, but time is limited to only 1, also stimulates the imagination. I understand from Carroll that (in connection with the issue about entropy) scientists still cannot really give a clear explanation for that one time dimension (there are theoretical models that take into account multiple temporal dimensions, but frankly this line of thinking seems very much like pure science fiction). And so we arrive at what may be the best quote that this book contains: "But the question remains: "what is time?" The response from the American physicist John Wheeler is worth remembering: "Time is nature's way of keeping everything from happening at once.” It may seem a very laconic way of representing things (not taking into account the quantum mechanical issues), but this statement certainly is unequivocal.
(rating 2.5 stars)