Black holes were once considered objects of science fiction. But now, they have been proved reality and are one of the most interesting objects in the universe. 

Black holes are known for their very strong gravity. Their gravity is so strong that no object can escape after being pulled into their gravitational field, not even light can escape from it. They are very massive objects that are 10 times to a few billion times the mass of our sun.

The thing that makes black holes to have a very strong gravity is its compactness. All the matter of a black hole is compressed so much that it only occupies a very small point in space, also called a singularity.

There are many ways a black hole is born, but most black holes are formed when a large star dies. When a large star dies, it then suddenly bursts into the universe’s most powerful explosion, a supernova. 

After the supernova, the remaining core of the star undergoes a sudden collapse due to its own gravity. The matter is compressed so much that the density reaches infinity at the center and a black hole is formed. Due to its infinite density, the gravity at the center of the black hole becomes infinite and it is called a singularity. You can consider a singularity a very small point with infinite gravity and density where the laws of physics, as we know them, are called breaks. 

Black holes can’t be seen with the naked eye or with a telescope because light cannot escape its gravity. Scientists found black holes by observing the light and objects around it. Black holes are perfect spheres and are featureless objects. 

Black holes can have many shapes and sizes, some the size of cities and others half the size of our solar system. But scientists are still not sure, what could be in a black hole?