Black holes are predicted by Einstein's theory of general relativity and are formed when massive stars collapse at the end of their life cycle. They have immense gravitational pull such that not even light can escape, creating a region of space-time known as the event horizon. Beyond this point, time stops and space ceases to exist, forming a gravitational singularity. Though small, black holes have such intense gravity that they can affect objects orbiting much larger stars and galaxies.

1. Black Hole

2. History
The Theory of General relativity was given by ALbert Einstein, which is about
the mysterious force which holds the moon around the Earth, the planets
around the sun and our solar system in the milky way.
Now, Einstein discovered that space and time are actually connected working
as one and heavy matter such as stars and planets bends & curves th space
time. This curvature defines the matter’s gravitational field, obliging the planets
to rotate around the sun and not even light can escape this curvature.

3. AFTER a few days of publication of his theory, Einstein received a letter
from another German astrophysicist Karl Schwarzchild, who had derived the
equation to calculate the distortion in space-time generated by a star.
Now, it was during a conference in paris, when a major mathematical flaw
was pointed out in the schwarzchild solution, which was later on called the-
“Schwarzchild Singularity”

4. When put simply, this singularity resembles an impenetrable black bubble,
where time stops and space ceases to exist.
After some observations, it was observed that this black sphere was
present at the centre of all celestial objects, let it be our milky way, our sun
or let it be Earth.
In our sun, this singularity is just 3 to 4 kilometers wide, & for it to become
visible, the entire mass of the sun would have to be condensed into this
sphere. Thus, Black holes are extremely dense and small in size. And being so
massive, they have such immense gravitational pull, not even light can escape.

5. Properties of a Black Hole
1) Photon Sphere
When light approaches a black hole, it doesn’t necessarily get sucked into the
black hole. Instead it starts orbiting the black hole. This point is called the
photon sphere, where, theoretically, you could see the back of your head on
your side, because the light bouncing off the back of your head would travel
all the way round the black hole & come back to your face. The light paths
are bent in a circle due to the immense gravitational pull of the black hole,
which causes the light to orbit the black hole.

6. The Point of No Return...
The EVENT HORIZON is the point which is infamously known as “the point of
no return” or “the edge of the world”, because that’s where time stops & you
can be sure of your now-inevitable death. Once you cross that point, you will
be stretched infinitely, the smallest molecules of matter inside you will be
violently “ripped” . The effect of this stretching is so significant, the scientists
don't call this stretching, but instead, they have termed the word-
Spaghettification