Black Hole Facts

Artist's concept of a black hole from top down. Image credit: NASA

One of the most awe inspiring phenomenon in space is the black hole. Black hole facts are searched for every day. Amateur astronomers as well as the professionals often ponder questions related to black holes. So, for the fun of it and because we want to help educate you, we here on Universe Today decided to put together a few black holes facts to intrigue your mind and satisfy a little of your curiosity.

Fact 1

As black hole facts go, this is basic one. A black hole is a place where the gravity well is so great that a gravitational time dilation has occurred. This causes time to stop. This causes an event horizon into which objects can fall or be pulled, but those objects will never reappear. That is the basic definition according to Einstein’s theory of general relativity.

Fact 2

There is no limit to how small or how large a black hole can be. The size and mass of a black hole are directly related. The more massive a black hole is, the more space it takes up. In fact, the Schwarzschild radius ( the radius of the event horizon of a black hole) and the mass are directly proportional to one another. Therefore, if one black hole weighs ten times as much as another, its radius is ten times as large. For example, a black hole with a mass equal to that of our Sun would have a radius of 3 kilometers, a typical 10-solar-mass black hole would have a radius of 30 kilometers, and so on.

Fact 3

The nearest black hole is 1,600 light years away. That is about 16 quadrillion kilometers for Earth.

Fact 4

One the interesting black hole facts is that they can not suck up all of the matter in the Universe. Each black hole has its own event horizon, much like the gravitational field of a planet. If matter is not in that horizon it will never get sucked into the black hole.

Fact 5

This one tips the scales on the heavy end as black hole facts go: there is a super massive black hole at the center of the Milky Way galaxy. It weighs in at about 4 million solar masses. Luckily, there is no reason to worry. This giant sucker is over 30,000 light years away.

Fact 6

The last of the black hole facts I have to offer today is that many theorists believe that a black hole can eventually evaporate. How is that? Steven Hawking proposed that black holes were not entirely black. They emit radiation. The energy that produces the radiation comes from the mass of the black hole. As the radiation is emitted, the black hole loses mass. The black hole emits more radiation the smaller it gets. In effect, a black hole evaporates more quickly as it shrinks.

These black hole facts are just a few of the little tidbits and teasers that you can find by doing some research. Here is a list of a few more. Here on Universe Today we have a great article about a practical use for black holes: as spacecraft engines. No one can get to a black hole without space travel. Astronomy Cast offers a good.

Sources: NASA Imagine the Universe, NRAO,