OCEAN FLOOR OPTICS : GLOBAL ESSAY

FAR down on the ocean floor, Earth is recycling its own skin. At certain boundaries, the huge plates of rock that make up the planet's crust crash into or over each other, pushing old crust below. At other junctures, these tectonic plates are spreading apart, allowing magma to bubble up and create entirely new stretches of seafloor. But the process is subtle and difficult to catch in action.…