A black hole is a mysterious region in space, where the force of gravitation is so strong that nothing can come out of it. Even electromagnetic radiation such as light can not escape the black hole. Because of this, we can not see the black holes with our naked eyes. Only space telescopes with special tools can help in seeing black holes. Black holes can happen only if a star is dying.
Black holes can be of any size. Even it can as tiny as an atom, but the mass of that black hole might be as large as a mountain.
According to the general relativity theory, adequately compressed mass in the space can form a Black hole. According to scientists, the smallest black holes were formed when the universe evolved. Stellar black holes were formed due to supernova.
Even scientists can not see black holes. If the stars go close to black holes, a high volume of light is made. Scientists with the help of satellite and special telescopes will identify those spots with black holes.
In April 2019, scientists were able to catch the image of a black hole. NASA released the first-ever photo of black holes on 19th April 2019.
image source -ichef.bbci.co.uk
A region of space having a gravitational field so intense that no matter or radiation can escape. Or in informal way "a place where money or lost items apparently disappear without trace"......
A black hole is a region of spacetime exhibiting gravitational acceleration so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. An artist's drawing a black hole named Cygnus X-1. It formed when a large star caved in. This black hole pulls matter from blue star beside it.
Black hole is a “place” in space that has gravitational pull so strong that nothing can pass through it – not even the light.
Interestingly, we can’t see black holes. They are invisible. They are dark (hence called “black”) because, again, lights cannot pass through them due to unimaginable gravitational pull.
So, how do scientists observe and know that there is a black hole?
Well, they don’t necessarily see the black hole but rather observe how stars and gas react around this “place”. Due to strong gravitational pull, gas and stars behave differently when orbiting around the black hole. When they are close to such a region, a high energy light is produced, which can be seen using satellites and telescopes. This light helps them conclude about the black hole presence and its possible size.
Black holes are of many different sizes. Some are as small as just one atom. And then there are those who have the mass equal to 4 million suns.
· Small black holes are called, well, small black holes.
· Black holes with up to 20 times the mass of the sun are called “Stellar”.
· The largest black holes are called “supermassive”.
Black holes are too far away from the solar system. So, they cannot destroy the earth. In fact, the nearest black hole from earth is 1,600 light years away.
(Courtesy: Quanta Magazine)
Coming to how black holes are formed?
The smallest ones are believed to have formed when the universe came into being.
The stellar ones are formed when old stars die and there’s a powerful explosion (called Supernova). This explosion is so powerful that the gravity overcomes the rule that keeps the building blocks of atoms from occupying the same space. This massive density creates a black hole.
In black hole, time is believed to be slow when compared to ours. This is in accordance with Einstein’s theory of General Relativity which states that time is affected by how fast you go. So, when something “falls” in the black hole, it travels an extreme speed. So, its time gets slower.
There’s a lot to be known about Black holes, including what’s beyond them. There’s plenty of fascination around them. Scientists around the world are actively working to know more about them.
(Courtesy: The Verge)
Of course, we would be dead (and so will our children) until anything substantial comes out from such studies and researches. But it’s incredible to even think that beyond that one point there could be another universe, is it not? It’s so fascinating to think about something that’s fundamental to our universe’s existence.
Hope this answers your question. :)