by Richard I. Gibson
The basic structure of the earth had formed by about 300,000,000 years after it began. This involved the further separation of denser and lighter materials, as well as things like water and gases being emitted to form the oceans and atmosphere.
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Image by Kelvinsong, via Wikipedia, under Creative Commons license.
The earths crust is as thin as 3 miles? Where?
ReplyDeleteOceanic crust is typically 3-5 miles thick under the oceans. Continental crust is much thicker, around 25 miles, but thinner in places and significantly thicker under mountain ranges. http://volcano.oregonstate.edu/education/vwlessons/lessons/Earths_layers/Earths_layers4.html
DeleteWas there already a solid core 300 million years after the Earth's formation, or was the core all liquid? And today, 4 billion years later, is the solid core slowly growing at the expense of the liquid core, or is its size static? A more comprehensive question could be this: which of these two is larger, heat generation by radioactive decay or heat loss by convection to the surface? In other words, is the interior of the Earth slowly cooling down or slowly heating up?
ReplyDeleteExcellent question. I'll add it to the list of future episodes because I think it will take some research - which is to say, the answer isn't simple. Thanks!
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