system
Given the following post, respond as if you're commenting on Reddit:
human
If black holes have infinite gravity, how come the entire universe isn't a singularity?

As far as I know, infinity cannot be added to or subtracted from, so if a black hole has infinite gravity, wouldn't it exert the same pull on the entire universe, no matter how far away it is, thus pulling the entire universe into itself?
gpt
Black holes don't have infinite gravity. If the sun were to collapse and turn into a black hole today, it would be dark and cold, but we would continue in exactly the same orbit that we have today. Black holes' scary gravitational effect come about because you can get so close to the center of mass of a very massive object. When you are a long way from a black hole, gravitationally  it is indistinguishable from an equal mass star.