Black Holes: Huge monsters?

 Learn about Black Holes: Part 1

Black holes are some of the strangest and most fascinating objects in outer space. They're extremely dense, with such strong gravitational attraction that even light cannot escape their grasp if it comes near enough. Most famously, black holes were predicted by Einstein's theory of relativity (1916), which showed that when a massive star dies in a supernova explosion, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the sun, the force of gravity overwhelms all other forces and produces a black hole. After decades of black holes being known as only theoretical objects, the first physical black hole ever discovered was spotted in 1971. 

Because light cannot get out, people can't see black holes. They are invisible. Space telescopes with special tools can't help find black holes directly; they see how stars and gases that are very close to black holes act differently than other stars. Astronomers must rely on detecting the radiation black holes emit as dust and gas are drawn into these dense creatures. Scientists can study stars to find out if they are flying around or orbiting a black hole.

They do not go around space eating stars, moons, and planets. Earth will not fall into a black hole because no black hole is close enough to the solar system for the earth to do that. Even if a black hole, the same mass as the sun, were to take the place of the sun, Earth still would not fall in. The black hole would have the same gravity as the sun. Earth and the other planets would orbit the black hole as they orbit the sun now (the sun will never turn into a black hole. The sun is not a big enough star to make a black hole). 

The main things to consider when learning about black holes are event horizons and singularities. The event horizon is that boundary of a black hole where even light can't escape if it crossed. The singularity is a single point in space-time where the mass of a black hole is concentrated. Let's learn more about these in the upcoming posts.