I saw this a few days ago on my cell phone – Collision liquified the 4th-largest asteroid, turning it into a dwarf planet: https://arstechnica.com/science/2019/10/collision-liquified-the-4th-largest-astroid-turning-it-into-a-dwarf-planet/ and thought it would make a good Space Saturdays post.
The bodies of our Solar System’s asteroid belt have violent pasts. Some, like the dwarf planet Ceres, have seen their interiors restructured under the force of gravity while having their surfaces blasted by collisions. Smaller asteroids have experienced collisions that completely shattered them, leaving their debris’ weak gravity to pull the pieces together into a rubble pile. Now, new images of the fourth-largest body in the asteroid belt, Hygiea, suggest it has a history that’s somewhere between the two. After suffering a shattering collision in the distant past, the body’s remains had enough gravitational pull to shape it into a dwarf planet.