CyberSpace! - the life of a star

Did you know...

...that a pulsar is a neutron star that emits pulsed radio signals?

...that a protostar is a portion of a nebula that is about to form into a new star?

...that some stars are 600,000 times as bright as the Sun?

Most stars are created from interstellar nebulae. These clouds of gas and dust are the birthplace of many stars. The particles within these clouds compress under their own gravity and, due to increased atomic collisions and other factors, heat up greatly. The new star then begins to fuse hydrogen atoms into helium. The majority of a star's life is spent in the fusion process, when its core is using up the elements within.

So, the larger the mass of a star, the shorter its life will be. When that process begins to come to an end, there are several possibilities:

for a Sun-sized star (1 solar mass):
1.		The star will eventually expand up to one hundred times its size, becoming a "red giant."
2.		As the helium in its core is used up, the star begins to shrink.
3.		The gravitational force in its core becomes so great that it crushes the star, creating a "white dwarf."
4.		The white dwarf continues for a long period of time to give off excess light.

for a small star:
1.		The star exhausts its fuel.
2.		The gravitational force from within its center overpowers the star and it is crushed into a "brown dwarf."

for a large star (10 solar masses):
1.		The star exhausts its fuel and begins to expand.
2.		The star expands into a huge fireball - a "supergiant."
3.		The supergiant explodes violently, radiating an immense amount of energy. This explosion is the "supernova." Many nebulae come from supernovae - the Crab Nebula is one of these. Four supernovae have been observed in the last thousand years: The Chinese witnessed one in 1054 AD, Tycho Brahe in 1572, Kepler in 1604, and the most recent occurred in 1987.
4.		The reamining part of the star is crushed by gravity and supercompressed into an extremely dense ball of matter - a "neutron star." Neutron stars are so named because they are compressed so much that the protons and electrons within the atoms are crushed together into neutrons. Pulsars are a type of neutron star that rotates and emit radio waves, sometimes resulting in a bit of unnecessary excitement by astronomers on Earth. (The regular radio pulse of the pulsar was initially thought to be a signal from an alien race.) The Crab pulsar is a neutron star in the Crab Nebula.

for an extremely large star (30 solar masses):
1.		The star exhausts its fuel and begins to expand.
2.		The star expands into a supergiant and experiences a supernova explosion.
3.		The huge mass of the star causes such powerful gravitational forces from the center that it becomes infinitely compressed.
4.		The resulting object is called a "black hole," from which nothing can escape. A black hole is also known as a singularity, from which scientists believe the universe was created. Theoretically, the universe could compress itself back into a singularity and explode, beginning the process again and repeating forever.