This is John Batchel, conversation with Miroslav Broche for Charles University, writing most recently in Nature magazine,

the origin of meteorites falling to Earth.

Five million years ago, seven million years ago, 40 million years ago, collisions in the asteroid belt sent meteorites all through the inner solar system,

finding their way to Earth. The big news, however, is what happened 466 million years ago.

And here, Professor Broch, Miroslav Broch, explains how it is that the Cambrian age, 500 million years ago, 466 million years ago,

meteorites from that collision are still raining down on Earth.

And what they did to Earth when they rained down here, what they changed,

it's a revelation about how we live in our solar system of violence and risk and chance.

Miroslav Broche, 466 million years ago, meteorites.

What does it mean?

More of this tonight.

It should be bigger, and it's very important to stress that we actually do have meteorites

from this event falling on Earth today.

It was very difficult to understand why such an old breakup is able to deliver something on Earth today.

Approximately one half of el-condroit meteorites exhibit this radiometric spike.

It's called shock age 466 million years.

Our discovery is actually that 466 million years ago, there was a breakup in

the asteroid belt, but a substantial part of these fragments are accumulated back onto the body.

So it was not a complete disruption and complete ejection. A part of the

material was reaccumulated back. And it was essentially preserved in the asteroid belt. And then

the second collision occurred, which ejected fragments which we still observe and

find on earth today.

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