A massive ocean floor lurks near Earth's core. Now, seismic imaging has revealed that it likely surrounds much — if not all — of the core.
This thin, dense layer is lodged roughly 2,000 miles (3,200 kilometers) below Earth's surface, between the core and the planet's middle layer, called the mantle. And it might encompass the entire core-mantle boundary, according to a study published April 5 in the journal Science Advances.
