A black hole is a region in space where the
pulling force of gravity is so strong that
light is not able to escape.
The strong gravity occurs because matter has
been pressed into a tiny space.
This compression can take place at the end
of a star's life.
Some black holes are a result of dying stars.
Because no light can escape, black holes are
invisible.
However, space telescopes with special instruments
can help find black holes.
They can observe the behavior of material
and stars that are very close to black holes.
How Big Are Black Holes?
Black holes can come in a range of sizes,
but there are three main types of black holes.
The black hole's mass and size determine what
kind it is.
The smallest ones are known as primordial
black holes.
Scientists believe this type of black hole
is as small as a single atom but with the
mass of a large mountain.
The most common type of medium-sized black
holes is called "stellar."
The mass of a stellar black hole can be up
to 20 times greater than the mass of the sun
and can fit inside a ball with a diameter
of about 10 miles.
Dozens of stellar mass black holes may exist
within the Milky Way galaxy.
The largest black holes are called "supermassive."
These black holes have masses greater than
1 million suns combined and would fit inside
a ball with a diameter about the size of the
solar system.
Scientific evidence suggests that every large
galaxy contains a supermassive black hole
at its center.
The supermassive black hole at the center
of the Milky Way galaxy is called Sagittarius
A. It has a mass equal to about 4 million
suns and would fit inside a ball with a diameter
about the size of the sun.
How Do Black Holes Form?
Primordial black holes are thought to have
formed in the early universe, soon after the
big bang.
Stellar black holes form when the center of
a very massive star collapses in upon itself.
This collapse also causes a supernova, or
an exploding star, that blasts part of the
star into space.
Scientists think supermassive black holes
formed at the same time as the galaxy they
are in.
The size of the supermassive black hole is
related to the size and mass of the galaxy
it is in.
Thank you and subscribe to please helium flash for more videos
