Many people view black holes as a massive cosmic recycling center. I know that, when I was younger, I
always thought of a black hole as being the universe’s vacuum cleaner, sucking up everything within its
path. As dramatic and as cool as it may sound, it is not quite true. I am afraid that this is a common
misconception about black holes.
When we look out into the universe, we find that most galaxies have a supermassive black hole at their
cores. The galaxies that don’t are mostly dwarf galaxies or irregular galaxies. Although there are plenty of
cases where a dwarf galaxy has a black hole at its core, a general rule of thumb is that an irregular galaxy
doesn’t, though there are some exceptions.
So should we expect to be eventually sucked into our supermassive black hole some day? Well, I
wouldn’t hold your breath or wait around. Our sun and some 200 billion other stars have been in a pretty
well defined orbit around the center of the Milky Way for billions of years and would continue for
indefinitely if it weren’t for the eventual collision with Andromeda.
The reason for this is that the same physics that determines the orbit of planets around the sun also
governs the movements of stars around the center of the Milky Way. Everything in our solar system orbits
around the sun, and has been doing the same for billions of years. This is because the sun is pretty much
the same mass as it was 4.7 billion years ago. If you were to replace our sun with a black hole of the
same mass the Earth and all the other planets would continue to do what they’ve been doing, the only
real difference would be that life wouldn’t be able to exist because it would be very cold without the sun’s
warmth. In short, a black hole is just a mass like any other