Black Hole Overview
A black hole is a region in space that pulls everything surrounding it towards itself that even light cannot escape. The Escape velocity of a black hole is more than the velocity of light which is 3 x 10 ^ 8 and since nothing is faster than light, it is impossible to escape from a black hole once you pass its event horizon. The event horizon of a black hole is the boundary of no return surrounding the black hole.
How can we see a black hole?
Black holes don’t let any visible light out and they seem like an empty region of space. That we can’t see a black hole or the surrounding matter doesn’t mean there is nothing in one. This is because of its strong gravitational field. The things inside of a black hole are lightly packed and cannot escape.
As a black hole gravity attracts matter and gas, it creates a swirling area known as the Acceleration disk. An acceleration disk is a structure often circumstellar disk formed by diffuse material in orbital motion around a massive central body. And because these different particles around a black hole move extremely fast, they start to heat up and emit x-rays and gamma rays. So, using specific telescopes and satellites, we can detect those rays and assume there is a black hole present.
Another way to spot a black hole is to notice the weird motion of interstellar material and stars that might point to the strong gravitational field beside them. The interstellar medium comprises primarily of hydrogen, followed by helium with trace amounts of carbon, oxygen, and nitrogen comparatively to hydrogen. The thermal pressures of these phases are in rough equilibrium with one another.
Types of Black holes
- Stellar Black holes
- Intermediate-mass black holes
- Supermassive black holes
- Ultra-massive black holes
- Stellar Black holes: They are formed when a massive star explodes with a much power that it shines brighter than the entire galaxy of stars. We call this occurrence the Supernova. A perfect example of a Stellar black hole is Cygnus X-1.
- Intermediate massive black holes: They are bigger black holes whose mass is about hundreds to thousands of times bigger than that of the earth’s sun.
- Supermassive black holes: As the name suggests, they are supermassive, one of those as with most galaxies, sits right at the middle of our galaxy, the milky-way. It’s called the Sagittarius A*. It has a mass that is 4.6 million times more than that of our sun. Another black hole that is supermassive is the 3C 186, which is 8 billion light-years away from us.Sagittarius A*
- Ultra massive black holes: As if the supermassive black hole is not big enough, we present to you a bigger one than Sagittarius A* and 3C 186. It is called the Ultra massive black hole. Examples of black holes under this category are the Holm 15A and the mighty Ton 618. We call it mighty because it is the most massive black hole to be discovered. It has a mass of 66 billion solar masses.