7: An Ocean of Magma

Earth's first oceans were hundreds of times deeper than the Pacific and made of molten rock. Where did they come from, where did they go? What stuff was in them, how do we know? Today, let's dive in and see how these oceans turned into today's mantle.

Extra credit: Drink a glass of ice water, watch The Core (2003), or see if you can find a garnet in your home or a museum.