So if you'd like, you could define life as being the ability to control and lower the entropy of some system. But there's always a total increase in the entropy of the entire environment.

Exactly. Yeah, yeah. So we take sunlight, which is pretty low entropy when it reaches us. We absorb it, we use its energy for stuff and we radiate heat away, which is much higher entropy. So we basically cannibalize off the entropy, the low entropy of starlight to be able to do all the cool stuff. So I'm a cosmologist and from that perspective, there's some interesting questions raised by the arrow of time and the second law of thermodynamics. After all, we've seen our 13.8 billion year cosmic history since the Big Bang, there has been an arrow of time the whole time. And that means the entropy of the universe has steadily increased as our universe is expanded and cool. But that means that if our universe is to be in the state we find it in today, it must have been in a very, very low entropy state in the Big Bang. And we don't know how or why it wound up in such an unlikely state. It's kind of like saying that our universes dice were all facing one shortly after the Big Bang. And we don't know why. We don't know how they wound up that way or what physical mechanism might have led to that. If you'd like to learn more about the arrow of time, I really want to recommend to you. Sean Carroll wrote this great book some years ago called From Eternity to Hear. He touched us on all the ideas we talked about in this podcast and digs a lot deeper into them. So that's my shout out to Sean in this great book.

This episode was produced and edited by me, Shalma Wegzman. Research and Writing is done by Dan Hooper and I. Dan is a theoretical physicist at Fermilab and the University of Chicago and is the author of many books, including most recently, at the edge of time, exploring the mysteries of our universes for a second. All music in Live This Universe is produced by Jake Klinebaum. Thank you so much for your support and for listening. And we hope you tune in next time to Why This Universe. Thank you.