Black Hole

Ever wondered what are black holes? They were first introduced in the early 1900s by Albert Einstein through his theory of general relativity. His endeavour led to an intense observation and research effort that has continued for over 100 years. Black holes are objects with so much mass that no force in the observable universe can prevent the escape of their gravitational pull, including light. The surface of a black hole is called the event horizon. It is a light crossing region at which no light can escape, trapping anything inside its gravitational pull. 

The Black Hole Theory

It is thought that stellar-sized, i.e., equivalent to the size of a star (20 times larger than our sun), black holes form when massive stars collapse at their end of life. The black hole theory states that black holes are not points in space but highly heated and flattened stellar remnants that, for various reasons, have a strong gravitational field. Models also show how this may change over time due to angular momentum slowing or “flattening”.

What Are Black Holes Made of?

Black holes are made of the same matter as stars: hydrogen and helium. The difference between black holes and stars is that a black hole has so much mass that its gravitational pull is more substantial than even light. They are believed to be formed from a small star that collapses at the end of its life cycle. 

As a star collapses, it becomes smaller and smaller until it reaches a critical size where it matches supersonic speed (velocity more significant than the speed of light). When this happens, gravity causes the core to collapse into a small and dense point with a potent gravitational force.

Types of Black Holes

• Stellar Black Holes: Stellar black holes form when massive stars undergo gravitational collapse at the end of their evolution. 

• Intermediate Black Holes: Intermediate black holes are the remains of massive stars that collapse into black holes after their core energy source is exhausted.

• Supermassive Black Holes: Supermassive black holes can be found in the centre of galaxies, and the reason for their existence is still not known.

Some important aspects of A Black Hole

Accretion disks

Black holes contain large amounts of light-sized “accretion disks”. Accretion happens due to gravitational acceleration and friction from gas streaming past the surface of a black hole. The shape of the accretion disc can be approximated from classical calculations and thermal radiation emission from the disc while it is still cooling.

Event Horizon

There is a limit to how close an object or matter can approach a black hole called the event horizon. The matter can escape and pass beyond this boundary, but nothing can escape its gravity. The event horizon is thought to have been created by a spinning vortex (a cloud of space dust). It becomes more spherical as it attracts objects in orbit around it, which causes it to spin faster. A star that has passed its life cycle stage collapses into a dense object with so much mass that light cannot escape from the object’s gravity.

What Is Inside a Black Hole?

One of the most puzzling questions is what is inside a black hole. There is a central core of space-time, an event horizon, just outside the black hole. According to current observations and simulations, this region is surrounded by a superheated accretion disk. There is a zone of falling toward the event horizon at the event horizon. That results in orbits with higher and higher energies until the black hole’s gravity becomes so strong that not even light can escape its pull. This zone is known as the “Photon Sphere”. Material entering this sphere cannot escape and will be trapped forever.

Conclusion

Black holes are mysterious objects that we still do not fully understand. So far, we know they are objects with so much mass that no force in the observable universe can prevent the escape of their gravitational pull, including light. Black holes are made of the same matter as stars: hydrogen and helium. The difference between black holes and stars is that a black hole has so much mass that its gravitational pull is more substantial than even light. They are believed to be formed from a small star that collapses at the end of its life cycle. Much research has been done into the theory of black holes, but there is still no clear picture of how they form or how they grow or shrink over time.