Have you ever heard about Black Holes? What are they, where are they found? If not, let me give you answers to all these questions.
Black holes are some of the most fascinating and mysterious objects in the universe. They are extremely dense regions of space where gravity is so strong that nothing, not even light, can escape. These form when massive stars die and collapse in on themselves. The resulting black hole is incredibly small and dense, with a gravitational pull so strong that it can suck in nearby matter, including stars and gas.

Black holes are often surrounded by a disc of hot gas and dust, called the accretion disc. This disc is heated by the black hole’s gravity and can emit X-rays and other forms of radiation.

In simple words, a black hole is a place in space where gravity is so strong that nothing, not even light, can escape. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying. Because no light can escape, people can’t see black holes. They are invisible. The pictures of black holes are captured by special X-ray cameras, which can detect various forms of radiation, found in observatories or satellites. The Event Horizon Telescope (EHT) captured the first picture of a black hole in 2019.

The largest black hole ever captured is TON 618, with a mass of 66 billion Suns! It is located about 18.2 billion light-years away from Earth.

A black hole is divided into six parts:

Accretion Disc
A disc of superheated gas and dust whirls around a black hole at immense speeds, producing electromagnetic radiation (X-rays, optical, infrared, and radio) that reveals the black hole’s location. Some of this material is doomed to cross the event horizon, while other parts may be forced out to create jets.

Event Horizon
This is the radius around a singularity where matter and energy cannot escape the black hole’s gravity: the point of no return. This is the ‘black’ part of the black hole.

Relativistic Jets
When a black hole feeds on a star, gas, or dust, the meal produces jets of particles and radiation blasting out from the black hole’s poles at near-light speed. They can extend thousands of light-years into space.

Singularity
A singularity is a point in the centre of a black hole where the laws of physics as we know them break down. It is a point of infinite density and gravity, where matter is compressed into an infinitely small space.

Photon Sphere
The photon sphere is a region around a black hole where the gravity is so strong that light can orbit the black hole. It’s like a special path where light can travel in a circle. This is because the black hole’s gravity bends the path of light so much that it can go in a full circle. The black hole itself, however, is dark.

Innermost Stable Orbit
The inner edge of an accretion disc is the last space where material can orbit safely without the risk of falling past the point of no return.

Black holes are found all over the universe. They can be found in the centres of galaxies, like the one in the centre of our own Milky Way galaxy. They can also be found in binary star systems, where they orbit another star.

These are truly the most fascinating and mysterious objects in the universe. They are incredibly powerful and can teach us a lot about gravity and the nature of space and time.

Hitarthsinh Gohil (VIII-G)