This process occurs on the deep ocean floor, where light cannot penetrate ... focus on deep-sea areas in the Pacific Ocean, including parts of the hadal zone, which extends to depths of 36,000 ...

The stronger currents, known as "giant whirlpools" or eddies, may reach the seafloor at the deepest parts of the ocean ... of sediment on the ocean floor over tens of millions of years.

More finely detailed maps of the surface of Mars may exist than of the remotest parts of the ocean floor. Scientists don’t often explore their slopes firsthand—or even their shallower summits ...