From Eternity to Here

From Eternity to Here

Sean Carroll is a scientist with a deep appreciation of the mystery of time: Why does it appear to “flow” from the past to the future and not vice versa? In From Eternity to Here, he offers an engaging tour of ideas from thermodynamics and cosmology, showing how they suggest a resolution.

In his first section, Carroll reviews the Second Law of Thermodynamics—the dictum that entropy (a measure of disorder) in a closed system only increases or stays the same—along with an overview of cosmic evolution from the Big Bang onward. He follows this with a look at how Einstein’s relativity theories altered our notions of time, and ponders the paradoxes inherent in “closed timelike curves,” which—if permitted by the laws of physics—would let us visit the past.

Carroll next focuses more deeply on the notion of entropy. He shows that it is natural for entropy to increase on average, but only if we assume a “Past Hypothesis” that it was very low in the universe’s distant past. In his final section, Carroll draws on the notion of a multiverse to suggest an answer to the directionality of the arrow of time. Imagine, says Carroll, that our universe is just one of many; specifically, imagine that “eternal inflation” is a real phenomenon, with parent universes constantly giving birth to baby ones. It can be shown that these baby universes start out with low entropy—as did our own universe at the era of the Big Bang. Time’s direction is a product of this initial state of low entropy in our universe.

Puzzled by time? From Eternity to Here puts a cosmic perspective on an age-old mystery.

“… a wonderfully accessible account of some of the most profound mysteries of modern physics” —Sir Roger Penrose, University of Oxford, author of The Road to Reality and The Emperor’s New Mind

Hardcover: 320 pages

Publisher: Dutton ( October 15, 2009 )

Item #: 34-2885

ISBN: 9780525951339

Product Dimensions: 6.0 x 9.0 x 0.0 inches

Product Weight: 20.0 ounces