From The Los Angeles Times:
In his studies of entropy and the irreversibility of time, Caltech physicist Sean Carroll is exploring the idea that our universe is part of a larger structure.Caltech physicist Sean M. Carroll has been wrestling with the mystery of time. Most physical laws work equally well going backward or forward, yet time flows only in one direction. Writing in this month’s Scientific American, Carroll suggests that entropy, the tendency of physical systems to become more disordered over time, plays a crucial role. Carroll sat down recently at Caltech to explain his theory.
What’s the problem with time?
The irreversibility of time is sort of the most obvious unanswered question in cosmology.
Time has been talked about in cosmology for many years, but we have a toolbox now we didn’t used to have.
We have general relativity, string theory, discoveries in particle physics that we can use to help us find the right answer.
What does entropy have to do with all this?
The most obvious fact about the history of the universe is the growth of entropy from the early times to the late times.
The fact that you can turn eggs into omelets but not vice versa is a thing we know from our kitchens.
You don’t need to spend millions of dollars on telescopes to discover it.