Black holes were first predicted by Einstein's theory of relativity in 1916. They are regions of space where gravity is so strong that not even light can escape. Black holes are formed when massive stars collapse at the end of their life cycles. There are two main types - stellar black holes, which are 10-20 times the mass of our sun, and supermassive black holes at the centers of galaxies, which can be millions of times more massive than the sun. Though once theoretical, black holes are now understood to exist throughout the universe and have profound effects on the structure and evolution of galaxies.

1. By
Amita Vadlamudi

3.  Black holes are arguably the most bizarre and
fascinating things in outer space. For years,
people have conjured up theories about black
holes but their existence was first predicted by
Albert Einstein in 1916 with his general theory
of relativity. However, the term ‘black hole’
was coined much later in 1967, by American
astronomer John Wheeler.

4.  A black hole is defined as a dense place in
space where the gravitational pull is so strong
that even light cannot manage to escape. If
anything ventures too close, be it a star or
spaceship, it will be compressed and stretched
by a process called spaghettification. As no
light can get out of it, people cannot see black
holes.

5.  Black holes are most commonly formed as the
result of a supernova, the death of a massive
star. When a star has worn out the internal
thermonuclear fuels in its core, the core is
rendered unstable. This causes the core to
gravitationally fall inwards upon itself,
explaining the nature of the black hole.

6.  Scientists have theorized several types of black holes,
including stellar, supermassive, intermediate and
miniature. Out of these, stellar and supermassive black
holes are most common.
 Stellar Black Holes
 They are formed by the death of massive stars. They
are about 10 to 20 times the mass of the sun. It is
believed that there could be millions of stellar black
holes scattered throughout the universe.
 Supermassive Black Holes
 Supermassive black holes are huge and can be millions
of times the mass of the sun. Scientists believe they
exist at the center of every large galaxy, including the
Milky Way.

7.  While black holes remain relatively unknown
up until the 20th century, there is more data on
their existence today. An unknown number of
black holes exist in the universe, constantly
altering entire galaxies and defying the concept
of space and time.