In the mid-20th century, when people looked at a map of the world, they saw the familiar continents surrounded by vast, ...

The image below shows a bathymetric map of the ocean floor, where pink denotes the shallowest water (continental shelves and ...

The map depicts the mid-ocean ridge zigzagging its way around the world. It looks like if you ran your fingers over the paper, you'd be able to feel where it rises and falls.

The image below shows a bathymetric map of the ocean floor, where pink denotes the shallowest water (continental shelves and oceanic plateaus), compared with the yellow-green of mid-ocean ridges ...

Deep Gravity. To map the seafloor, the satellites detect ripples and dips in the ocean's surface. Ridges and seamounts, or undersea mountains, are massive enough to exert a gravitational pull that ...

Topographic or satellite maps of Earth may reveal ridges and troughs that crisscross flat plains on the ocean floor, making it seem as though the entire ocean floor has been mapped out, Ferrini said.