The Birth & Death of Stars By John Busza

How Stars Are Formed All stars are created from gases and materials swirling around in space These gases are found in nebulas, such as the one in the background Gases and materials clump together until a gravitational pull is created More and more gases and materials are brought close together Once a the mass is large, dense, and hot enough, nuclear fusion begins

The Life of a Star A star uses nuclear fusion to produce energy The larger a star is, the less time it will produce energy A star the size of the sun will last for about 10 billion years, a star smaller than the sun for about 100 billion years, a giant star for a few million years, and a supergiant star for a million years

The Death of a Star Different stars have different deaths A star the size of the sun or smaller will condense into a dwarf star and simply fade away over time A giant star will create a supernova and then condense into a neutron star, which may create a pulsar A supergiant star will create a supernova and then condense into a black hole, which may create a quasar

Supernovas A supernova is created when a giant or supergiant star dies The core of the star collapses and creates a colossal explosion Supernovas are visible for a short time, and send huge amounts of gases and material into space These materials usually create nebulas

Black Holes Black holes are formed from the remains of a supernova from a supergiant star These remains are packed into one tiny, extremely dense mass The gravitational pull is so strong that nothing can escape, even light, hence the name “black hole” It is believed that there is a black hole in the centre of our galaxy

Pulsars Pulsars occur when a neutron star is very small and dense This size creates large amounts of electromagnetic radiation, which is only visible on the two opposite poles of the star A pulsar is a very rare event

Quasars Quasar is short for QUASi-stellAR radio source A quasar occurs when a stars output level is greatly reduced, and then suddenly increased This only occurs when it is being sucked into a giant black hole

Works Cited List Hamade, R. (1996). Black Holes. Retrieved May 18, 2006, from Cambridge Relativity and Cosmology Web site: http://www.damtp.cam.ac.uk/user/gr/public/credits.html Hirsch, A.J. (1999). Science 9. Scarborough, Ontario: Nelson. Sipiera, P. (1997). Black Holes. New York, New York: Children's Press. Pulsar. (2005). In Wikipedia [Web]. Retrieved May20, 2006, from http://en.wikipedia.org/wiki/Pulsar Quasar. (2005). In Wikipedia [Web]. Retrieved May20, 2006, from http://en.wikipedia.org/wiki/Quasar Tyler, P. (2003). Supernova. Retrieved May 16, 2006, from NASA'S HEARSARC Web site: http://heasarc.gsfc.nasa.gov/docs/snr.html