Can black holes really suck things up?

Yes and no. If you are more than twice the diameter of the black hole away from it, the black hole acts just like any other mass and will only affect you if you happen to dive directly for it. If you are inside this limit, however, the mathematics show that no stable orbits are possible because of a phenomenon predicted in general relativity called 'frame dragging' or the 'Lenz-Tirring Effect'.

Black holes, in general, do not suck, unless you find them on your final exam. Then they can suck big time. The above image is from Terry Herter's Cornell University astronomy course online notes.

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