In previous entries we discussed the topic of what happens when a person falls into a black hole. In particular we followed the course of events for an extremely massive type of black hole called a supermassive black hole. It turns out that, like shoes, black holes come in a variety of sizes.
There are postulated to be primordial black holes, or tiny ones at or smaller than the mass of the Earth which may have been formed close to the time of the Big Bang. There are also black holes that have weights approximately equal to a few times that of the Sun. At the extreme end of the mass range, there are also black holes that have weights 10-100 million times that of the Sun, the 'supermassive black holes.'
Such heavyweights are found in the centers of every large galaxy for which we have the ability to measure their presence. Even our own Milky Way galaxy appears to harbor a supermassive black hole in its center. Although we find them in the centers of galaxies in all cases, astronomers still do not understand exactly how a supermassive black hole was able to become a basic part of the anatomy of a galaxy.
We think that individual stars with masses of about 8 times the mass of the Sun or larger can form a black hole at the end of their lives. Over time, one can imagine that these dense ‘stellar mass
black holes’ eventually make their way to the center of the galaxy in which they were born. In turn, such smaller black holes and other stars and gas get assimilated into the supermassive black holes.
So it is not a big mystery that a supermassive black hole should grow over time by eating any material that falls into it. And I find that the public often have an intuition for such exotic events.
Interestingly, a supermassive black hole suffers from 'heatburn.' As the black hole consumes material in its belly, an enormous amount of energy comes back up. As an example, when just one star the size of the Sun falls into a black hole enough energy is produced to outshine the entire galaxy!
Unfortunately, there are no Tums tablets large enough to help, and
lucky for us, the Sun is no where near to this supermassive black hole! As the joke goes, a black hole walks into a bar and exclaims suddenly, ‘Hey where did everybody go?’