The Earth is round because it is a large body, and gravity tends to make large bodies round because that is the gravitational efficient configuration for the matter to be in.\n\nThere are a few reasons you can encounter non-round bodies in space:\n\n1) the object is small (for example asteroids), so it's gravity has less say proportionally on the shape\n\n2) It has experienced a catastrophic collision with a large body\n\n3) It is under very strong rotational or tidal forces\n\n4) It is expelling matter/energy in the form of cosmic jets, nova ejecta, etc.
why is the earth round?