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The Earth and Beyond

Stars  -  Life Cycle  -  Supernova  -  Neutron Star  -  Black Hole.

A large star will become highly unstable at the end of its red giant phase.
It can contract very rapidly
and undergo a violent explosion called a supernova.

During the explosion the star can become intensely bright
for a very short period of time.
A single supernova can be as bright
as all the other stars in the galaxy added together.

The outer part of the star,
which may contain a large number of heavy elements,
is blown into space and can form the substance of new solar systems.

The central core of the star is compressed
into a super-dense material and forms a neutron star.
The core is made of neutrons squashed together (see Atomic Structure)
and may be one million times as dense as a white dwarf.
This very dense material has a very high gravity
(if you are not sure what a neutron is,
see the GCSE Chemistry site).

If the core of a neutron star is very big
then the gravity is so great that the material becomes infinitely squashed.
It is now so small that it hardly exists at all
but the gravity is so enormous that not even light can escape it.
It is called a black hole and anything nearby
gets attracted inside and crushed out of existence.
Black holes make up part of what is called dark matter.

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Copyright © 2008 Dr. Colin France. All Rights Reserved.