This is CBSI in the world. I'm John Batchel with Greg Branach, a cosmochemist, a staff scientist at Lawrence Livermore Labs, and the author of Impact, a new book about asteroids and things that fall to Earth. But reasoning backwards, like a detective, no, as a detective, Greg is going to take us to the asteroid belt.

And what the asteroid belt and other objects in our solar system called planets, not all of them are planets, but it's important to mention that the building blocks of planets are everywhere. What they tell us about

the formation of our solar system. So far, Greg, my understanding is the planets have moved.

Why is the asteroid belt where it is after Mars? What does it represent?

That's a great question. And you're right. The planets have moved over the course of history of the solar system.

And particularly the large planets, Jupiter and Saturn, they encompass a huge amount of mass in our solar system, not in part of the sun.

And their kind of gravitational interactions with the Sun are what cause things to kind of move around because they're so large and they play such an important role.

And the reason the asteroid belt is where it is is because of this movement of the planets.

There are different resonances, basically, kind of zones that are gravitationally, you know, well set up to be.

And that's one of the zones where a lot of the

sweepings from the asteroid, or sweepings from the solar system ended up in that asteroid belt.

And the asteroid belt is the origin of many of these rocks that fall on Earth.

And not entirely, but many of them. And they're very large asteroids, and then they're

small asteroids. And I understand

there have been collisions. And sometimes you can walk the cat backwards to where the collision

took place. There was a NASA probe to Series and Vesta. Is that the other one? And are those

planetesimals or large asteroids?

There are many words for them.

Are they the origins of some of our meteors?

Have we linked things that fall to Earth from those large asteroids?

Yeah, particularly Vesta.

We're able to kind of match what we know Vesta is made of from spectral lines using these probes that we send up and ground-based telescopes, two samples we have on the ground that we can look at in the lab. And there's a pretty good match. And so we believe a lot of these samples, or at least one group of these samples, has come from Vesta. And we've done this with, you know, of things like Mars as well, the moon, and we can kind of figure out where some of these

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