Why aren't asteroids round?
Most asteroids are too small for their gravity to pull them into a ball, so they stay lumpy, like potatoes or peanuts.
Planets and big moons are round because they are so heavy that their gravity pulls everything towards the centre equally, squashing them into a ball. But most asteroids are much smaller and lighter, so their gravity is too weak to do this.
Imagine a giant lump of clay. If it were the size of a planet, its own weight would squeeze it into a sphere. If it were the size of a hill, it would keep whatever shape it had. Asteroids are like that hill. They keep the shapes made by collisions over billions of years.
Spacecraft photos show asteroids of all kinds of shapes. Itokawa looks like a sea otter or a peanut. Eros looks like a stretched saddle. Ryugu and Bennu look like spinning tops, with a ridge around the middle. Some asteroids are made of two lumps stuck together, called contact binaries.
Only the very largest asteroid, Ceres, about 940 kilometres across, is big enough to be nearly round, which is why it is called a dwarf planet. Vesta, about 525 kilometres across, is almost round but has a giant crater that took a bite out of it. Scientists think a body needs to be several hundred kilometres across for gravity to make it round.