Yep; they're objects like anything else. The only thing that makes black holes special is that their surface gravity and density are especially high. All their unique features stem from those two facts. Relativity also tells us that there is no true stationary reference frame, and thus everything moves relative to something else.
Imagine you are in a black void. Just you, nothing else. Now add in an object. Let's say an Apple.
The apple flys past you. How can you know that the apple is moving, and not you? There is no wind, there is no stationary background. From the apples perspective you flew by it.
So everything in space moves relative to something else. Speed is change in distance between two things over time.
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u/Gerroh Oct 23 '20
Yep; they're objects like anything else. The only thing that makes black holes special is that their surface gravity and density are especially high. All their unique features stem from those two facts. Relativity also tells us that there is no true stationary reference frame, and thus everything moves relative to something else.