Astronomy 101: From the Sun and Moon to Wormholes and Warp Drive, Key Theories, Discoveries, and Facts about the Universe (Adams 101 Series)

by Carolyn Collins Petersen

tectonism. This affects the outer layer of a planet or a moon, and it happens very slowly. It’s caused by heat escaping from under the crust of the planet. As it does, it warps the surface, causing it to fold or create faults (fractures).