Re: Why are planets all basically spherical?

Hiya,

Thanks for your question. This is basically just a result of the force of 
gravity! Gravity pulls the particles and components that form the planets 
together to be as close as possible; the most efficient way for this to 
happen is to form a sphere, which gets the most "stuff" as close as 
possible to the centre. 

Those planets, like Jupiter, which are noticably flattened obtain their 
shape from their rotation, which pushes outward the equitorial reigons 
(which are moving faster than the poles)

Chris Lintott