The Origin of the Universe and the Arrow of Time

Abstract

One of the most obvious facts about the universe is that the past is different from the future. We can remember yesterday, but not tomorrow; we can turn an egg into an omelet, but can't turn an omelet into an egg. That's the arrow of time, which is consistent throughout the observable universe. The arrow can be explained by assuming that the very early universe was extremely orderly, and disorder has been increasing ever since. But why did the universe start out so orderly? I will talk about the nature of time, the origin of entropy, and how what happened before the Big Bang may be responsible for the arrow of time we observe today.