It's season three of the joy of why, and I still have a lot of questions, like, why do birds flock and fish school?

You see the group behaving as this sort of undulating fluid. It's really the density and the turning of the individuals that percolates across the group.

What is this thing we call time? The English word time covers a lot of ground.

When I say the time is what clocks measure, that's more than an operational statement.

Why does altruism exist in the animal kingdom? We're part of a social species, which depends upon

altruism to help us stay coordinated and bring us all the benefits

that we need to make it through this life. And where, where is Janelle Levin? Jana.

I'm here, astrophysicist and co-host. Ready for anything. That's right. This time around,

I'm bringing in the A team.

And we are definitely going to be challenged by curiosities and connections from the macro to the

micro. It's the dream of a serious neuroscientist to be able to get these big psychological terms,

consciousness, ego, down to a single molecule or a single

methyl group. You might say we've solved the mystery, but I think it would be more accurate to say

that we've wrapped all the mysteries into one, which is why was there a big bang in the first place?

And there are millions of ways to explore this world of ours.

When you do good mathematics, it's not just pushing symbols around.

You do feel like there is some actual object that you're trying to understand.

So brace yourselves.

Get ready to learn.

What's the worst that could happen?

The worst thing would be if all of the problems were solved.

I'm Steve Strogetz.

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