Which the universe does not because,it was the first thing that exploded.
But, if theres no force affecting it, it should have a uniformed rate of expansion, which it doesnt, its expanding faster.
does anyone know what is the speed of gravity? is it instantenous?
Its a force, the bigger the mass, the higher the attraction. EDIT: And yes, Czae is right (Forgot to mention that bit!)
Is it not anti gravity that pushes all things apart in the universe?
Some say the universe is stretching, with the clusters of matter drifting apart due to the expansion... Imagine putting dots on a flacid (I love that word) ballon with a felt tip pen then blowing it up... That effect... So whatever is making it expand, is certianly out there, yet somehow, I cannot see it being gravity, or a anti version of it.
In the words of a wise man... "God knows" ;)