“Entropy shakes its angry fist at you for being clever enough to organize the world.” -Brandon Sanderson
The universe was born hot, dense, expanding, full of matter, antimatter and radiation… and in a low-entropy state. If entropy is a measure of disorder, though, that sure does sound like an awfully high-entropy state, not a low-entropy one. So why, when we talk about the Universe, do we say that the early Universe had such low entropy?
The answer has much more to do with a comparison to the entropy of the Universe today, as well as in the far future. Today, the entropy is some quadrillion (or 10^15) times larger than it was around 13.8 billion years ago. And if we extrapolate into the very far future, it will be another 100 quintillion (10^20) times bigger than it is today. But what’s responsible for the difference?
(And sorry, no Comments of the Week tomorrow; come back next week for a double dose, and I’ll see you for more science here on Monday!)