If a Black Hole came near Earth, would everything go dark?
In astronomy the term “near” has a somewhat different meaning than the rest of humanity uses. Alpha Centauri at about 24 trillion miles is very near. So is the M31 galaxy in Andromeda, at least when compared with most galaxies. If an asteroid wanders by us at a 200,000 mile closest point of approach it is considered very near indeed. If your black hole entered the solar system, depending where the planets were at any moment, yes, bad things would happen, but no, things would not go dark. A black hole has the mass of a large star, so its gravity would effect our systems planetary orbits. Under certain circumstances our solar system could lose planets. Collisions could take place, but would be unlikely. Tides could be very high. It depends on how close to earth the object would pass. It is quite possible one could wander through without doing any real damage.
