He didnt say gravity is proved wrong As far as we are concerened here on earth, with everything that we encounter here Newton's laws work.
Science isnt something to believe or disbelieve in, science is an investigative method. The results of which can be disputed and dicussed and changed as new information is discovered. It is open to change.
A lot of questions here are arising from the fact that people cannot grasp the scale of the idea of the big bang. It is a theory but being unable to understand it does not prve that ther is a god... or whatever.