A Quick Explanation
Did you know that most neutron stars are the size of Rhode Island (2,710 km2 ) and a thimbleful of neutron star would weigh over 100 million tons? This is because a neutron star is a dying star that has contracted upon itself. A star is a large ball of gas in which hydrogen fuses with itself to create helium which then does the same. Once the produced element cannot fuse with itself due to lack of energy, the star collapses rapidly onto the center point. This can result in two events. The collapse of the star could be so violent that it tears a hole in space time creating a black hole, a singularity that absorbs everything within its event horizon. . If the star is very large it can become a supernova which is an explosion that can be seen millions of light years away. During the supernova, the immense pressure at the core of the explosion causes large amounts of matter to be compressed into a small space. All the matter of presses together so tightly that electrons, neutrons, and protons are separated into different layers. A neutron star with the diameter of Brooklyn, New York would contain 500 000 times the mass of earth.
Composition of a Neutron Star
Sources:
http://listverse.com/2007/12/19/top-20-amazing-science-facts/
http://en.wikipedia.org/wiki/Neutron_stars
