How can a black hole have mass if its a hole?
A non-rotating black hole isn’t really a hole. It’s called a hole because things “fall into it” and can’t get out. But it’s no more a hole than the Earth is a hole that a satellite risks falling into at any point. Sometimes the phrase “gavity well” is used instead. Larry Niven wrote a story called “At the Bottom of a Hole” The “Hole” in question is Mars, and the protagonist, a “Belter”, accustomed to living in space, is stuck there, down on the surface “at the bottom of a hole”.
