From Eternity to Here | Sean Carroll | 2010 | 464 pages
In From Eternity to Here, Carroll, a theoretical physicist and cosmologist, offers the [mostly, it seems] universally accepted principles of entropy as a foundation for a new theory of time’s arrow- one that suggests that time moves in simultaneously opposite directions among countless universes [context: we’re all living on one of a few billion rocks inside one of these universes].
Carroll looks closely at entropy, which in rough terms is the measure of a system's disorder or lack of predictability, plays in our past and future. The level of disorder in our universe, as dictated by the second law of thermodynamics, creeps up over time. According to the theory, the moment of the birth of our universe- the Big Bang- was a period of extraordinarily low entropy, and cosmic disorder and chaos have underpinned the expansion of the universe ever since.
Only Carroll argues that might not be the case. He suggests that too broad an application of entropy as an explanation for our expanding universe and those in our galactic neighborhood misses the possibility [probability, to him] that universes may not all expand indefinitely, and some are in fact experiencing time in reverse, which would introduce a tremendous amount of uncertainty into our current understanding of the role time and space plays in four dimensional universes like ours.
I didn’t get large parts of this thing. The book is both fascinating and frustrating; Carroll’s ideas are electrifying reinterpretations of time and space for anyone who is at all intellectually curious, but the book is stuffed with long and complex conceptual workouts seemingly better suited for a physics book or paper. His attempt at producing a laymen’s guide to his theory on this mark fails, but if you are up to the challenge, it’s a nice exercise to try and follow the machinations of a clearly brilliant mind.