What is "Singularity"?

A Singularity or Gravitational Singularity is a point in space-time where the mass of an object becomes infinitely denser and infinitely smaller. This is the place where all the laws of physics as we know it ceases to exist.

According to Singularity, before the big bang, all the matter, and energy of the universe were crushed to a point where the volume becomes zero(many times smaller than the size of an atom).

And then Quantum fluctuations kicked in, which resulted in the big bang and the ever-expanding universe as we know it.

With the help of Einstein’s "Theory of Relativity", physicists claimed that singularities exist inside the black holes.

According to Schwarzchild Radius, any object can become a black hole if its mass is crushed to a point where the volume becomes zero. At this point the curvature of space-time becomes infinite, and time becomes meaningless.

Nothing can escape from this point including light, because of the infinite gravitational force.

If it’s the case, then we will never be able to fully understand the singularity inside a black hole.

For example, your friend somehow got into the center of a black hole to research singularity. You send a message asking about what's happening inside. He receives your message and sends a reply to you. But you'll never receive his message as nothing inside can escape from it.