Black hole is a body whose gravitational field is so strong that nothing can come out of it- even electromagnetic waves (sunlight) also cannot escape from it. 

When a body has so much mass that it due to its own gravitational force, the body starts shrinking. As the radius decreases, the gravitational force becomes even more stronger. Eventually, the body keeps shrinking- shrinking and shrinking and becomes a point. Though how this happens, i.e. becoming a point of not or what happens after that, is still not known to scientists.

If anything falls into it, that things can never escape from it. It is like a swirling demon in universe that easts up all the things that come within its range called event horizon.

Do we need to fear from Black Holes! Our nearest black hole is at such a distance that we are not in danger for the next hundred years. Also, our sun is also not so big that it becomes a black hole.

Let’s talk about some strange things about black holes.

1. Black holes are not infinitely small. The more gravitational effects will increase, the smaller the star center will grow. Small, and small, and small … At one time it will come that it will reach such a size which is called Plank Length. This is a unit which is not possible in quantum mechanics. How long this is! 1 Planck Unit = 10-34 Meters

2. Everything near the black hole is bizarre- Black hole distorts the time-space with its gravity

3. Going into black hole causes death in a strange way- Assuming that the feet of a person are near the black hole, it will mean that the gravitational force on its feet will be much more than its head. This difference will be so much that the feet of that person will be pulled from the earth by its gravity to millions of times more force. The person will pull out and become like a long thread, and after that it will be broken.

4. There is too much glow around the black hole- The substance that falls in a black hole starts to orbit around the black hole. Due to excessive friction between the particles of matter, its temperature becomes high, this temperature reaches to millions of degrees. The substance at very high temperatures becomes very bright.

6. Black holes also rotate.