Monday, March 10, 2008

The Formation of Stars and Galaxies in the Universe

For a while after the Big Bang the Universe had almost no structure.  The Universe was a void filled with sparse amounts of Hydrogen, Helium (formed by early fusing of Hydrogen under high pressure), dark matter, and dark energy.  Then, as the Universe cooled, dark matter clumped together.  Gravity attracted gases and more dark matter to add to the clump.  A proto-galaxy had formed.  Within a proto-galaxy, pressurized gases formed the first stars.  It is believed that these stars had no metal content.  As the Universe continued to expand more galaxies formed, the very galaxies we look at today were created.  Developing proto-galaxies have been seen through telescopes about 13.2 billion light years away, making the age of the Universe there about 500 million years.

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