Cosmic Snowmen Gained Their Unique Shape After Gently Spiraling Into Each Other

Planetesimals start out as collections of pebble-sized objects that are bound together by gravity into a rotating cloud. But sometimes the cloud may collapse inward, self-destructing and forming two separate planetesimals. The new study’s simulations show that after this gravitational collapse happens, the planetesimals’ orbits bring them closer to each other until they gently come into contact. They then stick together, solidifying the snowman shape.