This is CBS, I Am The World. I'm John Bachelor. The world, the planet, the globe we have,

continents, and the theory of continent of drift is not a hundred years old. And yet,

where did the continents come from? A question I never asked until I read in Nature magazine,

giant impacts and the origin and evolution of continents. I welcome Tim Johnson, the executive

editor of Geological Magazine, as well as the deputy head of the School of Earth and Planetary

Sciences, Curtin University, Western Australia. Tim and his colleagues published in Nature magazine,

the premier peer-reviewed magazine on planet Earth that we're about to talk about. And they

approach the story of where did the continents come from, from Pilbara Crata. That's the oldest

pieces of the Earth that we have access to. There are many of them around the world and we'll

touch on a few of them. The Pilbara Crata is in Western Australia. And the question is asked,

what in this Crata, this ancient rock tells us the contest between the

bottom-up plume creation of continents coming up from the interior of the Earth to form the

surface of these continents that then start to break apart and drift versus the giant impact creation

of the continents that's top down. Tim, a very good day to you. Thank you very much for this.

And it's a joy to talk about the formation of something I never knew to ask. So we begin immediately

to make distinctions of the ancient Earth. You tell me the 4.5 billion years ago, to 4 billion

years ago, is called the Hadian period as in Hades. What happened then that creates the

conditions we're about to discuss? Good day to you, Tim. Good day to you. Thank you for inviting me.

It's nice to be here. So the Hadian, yes, he's named after the facts that it resembled Hadis,

a hellish world, but that's the brick definition. The Latin definition is actually based on

the word hidden. And that's probably appropriate because we know so little about the Earth in

that theion. So as you say, the Earth accrued it around 4.5 billion years ago. Shortly after that,

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