QUESTION:
Why are planets round?

Answer from Richard Glover on March 20, 1996:
Your question about why planets are round is very good. Planets and other
Celestial bodies are round mainly because of a force called gravity. this
force pulls on the dust and gasses in space, creating an object like the
sun. A disc of dust, rocks, and gasses will sometimes orbit this star.
the gravity of specific objects will pull some of this debris in and
create a larger mass. After spinning and attracting more particles, the
"Planetesimal" will become a planet. It will be round because the gravity
has uniformly pulled in particles.
Think of a marble as the center of gravity. As the marble spins through space
it attracts particles from every side. These build up and spin and create a
bigger ball.