When I say compacted, I mean really, ridiculously, unbelievably compacted. To the point where a black hole the size of a marble would have more mass than the entire Earth. Despite that, there are actually micro black holes that are so imperceptibly small that they have about the same mass as a flea's egg. On the other hand, there are black holes in that same category that have approximately the same mass as the moon. Is that sinking in? The smallest category of black holes range in mass from about the same as a flea's egg to about the same as the freaking moon.
|At black hole density, this would sink to the core of the Earth and cause very bad things.|
The next category up contains stellar black holes, which get up to about the size of Manhattan and have about ten times the mass of the sun. After that comes intermediate-mass black holes, which is where it starts getting harder to fathom. These get up to the size of the Earth and have the mass of one thousand suns.
Then we get into the last category. The supermassive black holes. These puppies are some of the biggest things in the known universe. They can reach up to 10 Astronomical Units in size. That's 10 times the distance between the Earth and the sun, which is about 93 million miles. Times ten. At that size, their mass could be the same as one billion suns. Supermassive black holes are, therefore, rather aptly named. Scientists believe that they exist at the center of every galaxy in the universe, which means we are currently orbiting a star which is itself orbiting an incredibly enormous distortion in space and time.
|The bright spot in the center is light being warped and consumed|
One more thing, and I think you know what it is. It's the burning question that always creeps up from the back of your mind when you think about black holes. What happens when you go into one? The answer, mostly, is that we don't know. What we do know, however, is what it would look like to observers.
So let's say your friend is in a spaceship headed toward a black hole, toward the point of no return known as the event horizon. As the ship gets closer, it seems to slow down - time is dilated in such a way that anything close to the event horizon appears to be moving slower and slower, until finally the movement is so small that it can't be seen. Eventually, it stops. As far as you're concerned, your friend is frozen in time forever. But that's just you. Your buddy will experience whatever there is to experience in the black hole. Probably death, I'm sure, but as it happens, time around him will pass. Infinitely.
Holy shit. That might be a little too heavy, so here's a puppy: