Why are Planets Round but Asteroids are Not?

All planets orbiting the Sun are spherical (round like a ball). This is because they were spinning at incredible speeds when they broke away from the Sun.

However, asteroids (minor planets) come in all sorts of shapes. Between Mars and Jupiter, millions of asteroids orbit the Sun. Astronomers have found that while there are about 200 asteroids larger than 100 km, they are not perfectly round. Instead, they look like irregular, broken chunks of rock.

Scientists believe asteroids are rocks broken off by celestial collisions. For example, an asteroid named Ida is square-shaped, while others like Vesta and Pallas look like giant jagged rocks. They are constantly colliding with each other and breaking into even smaller pieces.