Black Holes?

The theory of General Relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole.A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiations such as light can escape from inside it.

General Relativity:

General Relativity is a theory of gravitation(1907-1915).It developed with the equivalence principle which states that accelarated motion and being at rest in a gravitational field are physically identical.
Hence, an object in free fall is falling because that is how objects move when there is no force being exerted on them.
But in classical mechanics we know that an object free falls due to the force of gravity.
To resolve this difficulty Einsten first proposed that the space-time is curved by introducing Einsten Field Equation,which relates the curvature of space-time with mass,energy and momentum.
So, Einsten conclude that the rays of light bend in the presence of gravitaional field.

Origin of Singularity:

Einsten predicts the existence of singularity in the densest objects in the universe.Singularity in physics is the point where density is infinite,volume is zero and gravity is infinite which is better known as Black Holes.Even light cannot escape from the gravitational pull of the black holes.

Event Horizon Telescope:

The Event Horizon Telescope (EHT) make it possible that we can now see the real image of a Black Hole.The EHT captured a Black Hole at the centre of Messier 87 (M87) galaxy, 50 million light years away and 6.5 billion times heavier than Sun.

Note: Ours Earth’s Galaxy is Milky Way.
Light year is the distance travelled by light in one year.
1 Light year = 9.461×10^15 metre

Basic Fundamentals:

When the mass tends to infinity and volume tends to zero,the supermassive object warps space-time in such a way that even light cannot escape.Thus is the fundamental science that underlines Black Holes.

Event Horizon:

The boundary of a balck hole is termed Event Horizon .Objects that go beyond the Event Horizon are lost in the fuzzy whirlpool of space-time;hence the term Point of No Return.

Stephen Hawking Theory:

From Stephen Hawking’s groundbreaking work,we know that black holes aren’t totally black.They are able to emit jets of Plasma as well as create particle-antiparticle pairs near the Event Horizon.When matter comes close to the Event Horizon,it forms an orbiting disc due to the black hole’s gravity.Chunks of matter grind against each other,creating massive friction and releasing huge amounts of energy.The spinning warms up the disc.Thus,matter close to the Event Horizon glows brightly with heat equivalent to several hundreds of stars.
It is this bright glow which was imaged by the EHT’s network of eight radio telescopes.

Thus, the above study gives us clues to the fundamental nature of gravity,energy matter,space,time,space-time geometry and so on.