How are some black holes’ event horizons bigger than others?

Question

If their mass is always contained in a singularity and their density is infinite, how are some black holes supermassive and others are not?

In: 5

Answer 1

“Massive” usually means a thing has a lot of volume, but in astrophysics it means it has a lot of mass.

When things have a lot of mass sometimes they become smaller because of their own gravity so we can’t use their size to measure how “big” they are.

Even though all the black holes are compressed to the max (infinite density), some have more mass in there than others, and since mass is what causes gravity and gravity is what causes event horizons, some have bigger event horizons.