14
Oct
Some scientists think Earth's oceans formed when icy comets hit the planet. But new research suggests a different origin for the oceans: they simply seeped out of the center of the Earth.
The finding, published in Science, suggests that a reservoir of water is hidden in the Earth's mantle, more than 400 miles below the surface. Try to refrain from imagining expanses of underground seas: all this water, three times the volume of water on the surface, is trapped inside rocks.
