Planet Plates, Metal Moon, and Comet Cocktails
Caleb Scharf: Earth’s plate tectonics seem to be unique in the solar system. This constant production and recycling of a mostly crystallized outer layer not only speeds up the cooling of a rocky planet but seems to play a critical role in long-term climate stabilization and the resupply of chemical energy to the surface. But a key factor is the speed of plate subduction (where crust plunges back into the planetary mantle). A new study by Sobolev and Brown in Nature proposes a special connection between this speed and the lubricating nature of sediments coming from exposed continents on a world.