What is a black hole in space? Have you ever thought, what creates a black hole and what is inside the black hole? A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. Black holes are exotic structures where gravitational fields are so powerful that they trap everything, even light. They were first postulated by Albert Einsteins theory of general relativity. This can happen when a star is dying.
Facts about Black Holes
1. The closer you get to a black hole, the slower time runs.
2. Material that gets too close to a black hole gets sucked in and can never escape.
3. Black holes do not emit radiation on their own.
4. Though they are black they are invisible to us.
5. The density of a black hole is so great it would be like taking the whole Earth and crashing into a volume smaller than a marble!.
Formation of Black Holes and What is a Black Hole in space
If there is enough mass, the gravity of collapsing core will compress it so much that it can become a black hole. Stellar mass black hole has a few times mass of the sun. But there are also monsters, called super massive black holes. These are present in the centers of galaxies and are huge. They can be millions or billions of times the mass of sun! these are probably formed during the formation of galaxies. In a milky way, we are having Sagittarius A* as our super-massive black hole.
Black Hole Characteristics
Although black holes come in a variety of masses and sizes, their structures are all alike. A black holes entire mass concentrate in an almost infinitely small and dense point called a singularity. It surrounds by the event horizon. A rotating black hole surrounds by the ergo-sphere, a region in which the black hole drags space itself.
Size of the Black Holes
The more massive a black hole is, the more space it takes up. 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.