system
Given the following post, respond as if you're commenting on Reddit:
human
How close to Earth could a black hole get without us noticing?
gpt
It depends on the mass of the black hole. A black hole with the mass of, say, a person (which would be absolutely tiny) could pass through the Earth and we'd be none the wiser. If one with the mass of the Sun passed by, well, the consequences would be about as catastrophic as if another star passed through - our orbit would be disrupted, and so on.

The important thing to remember is that black holes aren't some sort of cosmic vacuum cleaner. For example, if you replaced the Sun with a solar-mass black hole, our orbit wouldn't be affected at all, because its gravitational field would be pretty much exactly the same. Black holes are special because they're *compact*. If you were a mile away from the center of the Sun, you'd only feel the gravity from the Sun's mass interior to you, which is a tiny fraction of its overall mass. But if you were a mile away from a black hole with the Sun's mass, you'd feel *all* that mass pulling on you, because it's compacted into a much smaller area.