What is Singularity?
Imagine throwing a ball in the center of black hole. The mass of ball will become zero and all the matter will be converted into energy! This means that the density at the center of black hole if infinite because the finite mass (in case of ball) is compressed to zero inside blackhole. Thus, at this point where the property becomes infinite is called “Singularity”. Seems interesting, Right? Let us go a bit deeper into this mind-blowing concept!
· Gravitational Singularity
Current theory suggests that, as an object falls into a black hole and approaches the singularity at the center, it will become stretched out or “spaghettified” due to the increasing differential in gravitational attraction on different parts of it, before apparently losing dimensionality completely and disappearing permanently into the singularity. An observer watching from a distance outside, though, would have a different view of the event. According to relative theory, they would see the object moving slower and slower as it approaches the black hole until it comes to a complete halt at the event horizon hence never actually falling into the black hole.
· Formation of Singularities
Singularities form by a collapse of a star, where star with high enough mass (above 30 times the sun) would shrink under its own gravity and force until it becomes a single, one dimensional point. When it forms, space and time would be infinite in there.
Let us look at this example. If a person were to stand on a collapsing star right before the singularity forms, and they sent a signal every second to a nearby observer, time and space would slow down as the singularity is being formed. The observer would hear the signal slowing down.
· If stars could become singularities, then Sun could also become a Black Hole!
This statement is quite astonishing but do not worry because the mass of Sun is too small to become a singularity! if our sun decreased to the size of the nucleus of an atom. It would be very dense. However, our sun does not have a high enough mass to become a black hole. It is well below the Chandrasekhar limit (maximum mass of a stable white dwarf star), which means it will shrink to a white dwarf, with radius of a few thousand miles. It can’t become a black hole because it is too small.
· A black hole’s singularity will remain hidden forever!
According to a hypothesis, behind horizon the singularity of blackhole remains concealed. This is because Singularity in blackhole is always surrounded by an area which does not allow light to escape! Hence cannot be directly observed.
Therefore, due to it is nature we will never be able to know or understand singularity completely. Although an observer can send signals inside the black hole, but it is not possible to get any signals back! So, the secrets and myths of blackhole will remain safe forever.
· Time stops in Singularity due to gravitation.
Black hole is perfectly black because nothing can escape it, not even time! It’s gravitational pull so powerful, that it distorts and wraps time and light. Now imagine a clock moving closer to a blackhole, the observer can detect the time getting slowed and slowed. When the clock reaches event horizon, the time will eventually stop. And in singularity the concept of time will be lost!
· Does this Universe come from a singularity?
Modern theories suggest that Big Bang occur due to the presence of Singularity, also known as Initial Singularity. The initial singularity is part of the Planck epoch (an era Big Bang cosmology immediately after the event which began the known universe), the earliest period in the history of the universe.
The initial singularity was a gravitational singularity of seemingly infinite density thought to have contained all the mass and space-time of the Universe. Quantum fluctuations caused it to rapidly expand in the Big Bang, hence, creating the present-day Universe.
