Basic Formation Huge clouds of dust and gas exist in space. Shockwaves from supernovas make the dust and gas condense together. The temperature rises in the cloud and causes a fusion.

Red Giants Once a star has used up the hydrogen in its core for fusion, the fusion takes place outside of the core. The core then heats up and expands, making the star larger and more luminous.

White Dwarfs Once a red giant has used up all of its hydrogen, it creates a planetary nebula. Once the nebula stops, only the core of the red giant remains. Stars will usually end their lives in this state.

Neutron Stars If a star is seven times the size of the sun, it will become a red giant fairly quickly. When its fusion stops, a central iron core remains. The temperature heats up dramatically and causes a supernova. A neutron star is the mass that remains.

Black Holes Neutron stars will eventually collapse because of gravity. They are then squeezed into a very small area and become very dense with a huge gravitational pull. This pull sucks in everything around it. http://www.seed.slb.com/en/scictr/lab/byo_star/index.htm