[Dracus]

I have done some more research.

There is no limit in principle to how much or how little mass a black hole can have. Any amount of mass at all can in principle be made to form a black hole if you
compress it to a high enough density. We suspect that most of the black holes that are actually out there were produced in the deaths of massive stars, and so we expect
those black holes to weigh about as much as a massive star. A typical mass for such a stellar black hole would be about 10 times the mass of the Sun, or about 10^{31}
kilograms. (Here I'm using scientific notation: 10^{31} means a 1 with 31 zeroes after it, or 10,000,000,000,000,000,000,000,000,000,000.) Astronomers also suspect that
many galaxies harbor extremely massive black holes at their centers. These are thought to weigh about a million times as much as the Sun, or 10^{36} kilograms.

The more massive a black hole is, the more space it takes up. In fact, the Schwarzschild radius (which means the radius of the horizon) and the mass are directly
proportional to one another: if one black hole weighs ten times as much as another, its radius is ten times as large. A black hole with a mass equal to that of the Sun
would have a radius of 3 kilometers. So a typical 10-solar-mass black hole would have a radius of 30 kilometers, and a million-solar-mass black hole at the center of a
galaxy would have a radius of 3 million kilometers. Three million kilometers may sound like a lot, but it's actually not so big by astronomical standards. The Sun, for
example, has a radius of about 700,000 kilometers, and so that supermassive black hole has a radius only about four times bigger than the Sun.

A black hole has a "horizon," which means a region from which you can't escape. If you cross the horizon, you're doomed to eventually hit the singularity. But
as long as you stay outside of the horizon, you can avoid getting sucked in. In fact, to someone well outside of the horizon, the gravitational field surrounding a black hole
is no different from the field surrounding any other object of the same mass. In other words, a one-solar-mass black hole is no better than any other one-solar-mass
object (such as, for example, the Sun) at "sucking in" distant objects.

A black hole in a close orbit around a star can pull the top layers of the star off the surface and
down its own gravity well. Once the material passes beyond the black hole's event horizon, it is
gone, and more stuff can be consumed by the black hole. You are left with a slightly larger black
hole, and a slightly less massive star, so the black hole can pull a little more material off the star.
This continues until the star is gone, and the black hole's hunger is yet unabated.