There are many theories for the begining of our universe, none more agreed on than the big bang theory. Before the big bang time and matter did not exist, there was just an infinetly dense point in nothing. Many people misconcieve the big bang as being an explosion in space, however it is nothing of the sort, it was an explosion of space.

Imediatly after the explosion everything was extremely hot. So hot that the positive pull of protons on electrons couldn't cause them to orbit the protons, electrons moved freely. Once the universe cooled down to enough, electrons started becoming pulled in by protons.

Gravity started to pull small particles into large clumps of bigger particles. These swirling particles would eventually become stars, and planets.

Total Information Sources from "Origins if Our Universe" Section:

LaRocco , Chris LaRocco , and Blair  Rothstein. " THE BIG BANG ." University of Michigan. N.p., n.d. Web. 18 Nov. 2009. http://www.umich.edu/~gs265/bigbang.htm.

"Lecture 1 : From the Big Bang to Stars." University of Turku. N.p., n.d. Web. 18 Nov. 2009. www.astro.utu.fi/~cflynn/Stars/l1.html.

"Solar System Formation." Astronomy Online. N.p., n.d. Web. 18 Nov. 2009. http://astronomyonline.org/SolarSystem/SolarSystemFormation.asp.

"  Solar System Formation." Windows to the Universe. N.p., 18 Jan. 1999. Web. 18 Nov. 2009. http://www.windows.ucar.edu/tour/link=/our_solar_system/formation.html.