system
Given the following post, respond as if you're commenting on Reddit:
human
Can black holes move?

This may be a silly question, but bare with me.

Could in theory a black hole have momentum like say a comet.  Traveling different galaxies and sucking up things that get close to it?

If so, what would happen if it passed through or collided with something like our sun?
gpt
Yes, black holes can and do move.  Keep in mind that all movement is relative -- if you are stationary compared to a black hole then it is not moving, while if you are passing by it at some speed then the black hole is moving.  There is no such thing as absolute movement.  Whether a black hole has momentum or not is entirely based on your choice of reference frame in which to observe the black hole.

But, while black holes move around inside galaxies, they don't generally have enough relative momentum to travel between galaxies.  They, like all other celestial bodies, tend to occupy a single galaxy.

If a black hole collided with our Sun, depending on the size and mass of the black hole it would likely consume at least part of the star and disrupt the rest.  Our orbit and solar system would be thrown into chaos and we would all die.  Fortunately, this is statistically very, very unlikely to happen which is why it hasn't happened already.  Space is *incredibly* vast, and black holes and other stars are quite dense and tiny compared to the distances between them.  Even when the Milky Way eventually collides with Andromeda and the two galaxies merge, our solar system is probably going to be perfectly fine and all the stars will just fly past and between each other, mostly unaffected.