system
Given the following post, respond as if you're commenting on Reddit:
human
How do Black Holes exist?  How do we know?

A friend of mine doesn't believe in Black Holes especially with the complex ideals.  Please tell me something that I can just read to him to prove/explain to him how Black Holes exist and why we know its there.
gpt
Black holes don't emit light so we can't directly see them, but because they have lots of gravity, some objects get locked into orbit around them just like the earth orbits the sun. We know they're there because we see stuff orbiting around them with telescopes.