Why are planets round?
Planets are basically round because gravity pulls uniformly in all spatial directions, in other words, a round shape tends to result from a spinning object with a large gravitational pull.
But did you know that this pull from gravity can be strong enough to create a bulge at a planets equator hindering the lovely round shape?
It s true; but scientists tell us roundness boils down to mass, size and rotational speed. So clearly, size matters.