A “roll cloud” spotted off the coast of Portugal looked like something out of a movie. Here’s the science behind it.

By . Anna Skinner is a Newsweek senior reporter based in Indianapolis. Her focus is reporting on the climate, environment and weather but she also reports on other topics for the National News Team.

Reporter. Humanity has only explored 0.001% of the deep sea, ... The deep sea refers to the part of the ocean below 200 meters (656 ft.), at which light begins to disappear.