By Dan Vergano, USA TODAY
That’s because the public-minded scientist is walking readers through his just-released From Eternity to Here: The Quest for the Ultimate Theory of Time. Every Tuesday, he guides folks through a chapter in an online book club.
Ain’t the Internet grand, folks? This is the closest most of us will get to taking a Caltech class.
“Time is something we are all familiar with, but most of us don’t think about,” says Carroll. “Thinking about it a little more deeply can lead us to some grand speculation.”
In the book, Carroll recounts the history of scientists thinking about the “arrow of time,” the clock’s curiously one-dimensional march ever onward (we have up and down, right and left, backwards and forwards, but time just zips along ever forward). In particular, he revisits some of the 19th century thinkers, such as statistical physicist Ludwig Boltzmann, overshadowed today by 20th century icons like Einstein.
Boltzmann and colleagues put entropy, energy’s tendency toward disorder, on a statistical basis, offering a physics interpretation of time. Time results from entropy sending events, everything from the egg scrambled for your breakfast to stars running out of steam over billions of years, heading relentlessly one-way, never to unscramble themselves or restart their fires again.
One of the mysteries of the universe is its beginning in a highly-ordered low-entropy state, a hot, dense ball of energy some 13.7 billion years ago called the Big Bang. (Which was low-entropy in the sense that its energy was so useful for making stars, galaxies, planets, people and everything else, energy once spent that it couldn’t be re-ordered like that breakfast egg that could be scrambled, poached or served sunny side up, but never put back together again.) “Why highly-ordered but not perfectly ordered,” Carroll asks, pointing to…