Jill

 The Big Bang. -univerise has a begining (between 13 and 20 billion years ago) -singularity (very very small and very very hot) everything came from an intial tiny ball of inifinite density which expanded into the universe we know today. -expansion (continually expanding)

The Formation of the Solar System - explosion of a nearby supernova - squeezing of resulting cloud -> cloud collapses under its own gravity -> solar nebula forms - nebula spins, becomes hotter and denser in the center -particles stick together and form clumps -> moons and planets. planets like Earth form near the hot center because rocky material could stand the heat. Planets like Jupiter formed farther away from the center. - cloud continues to fall in, center becomes extremely hot and eventually became a star (the Sun, this reaction had enough pressure to trigger the nuclear reactions that power the Sun). then there was a stellar wind cause by solar explosions that blew the rest of the dust (helium and hydrogen). the wind was more powerful near the Sun. this is why the inner planets are more rocky than outer planets.

__**References**__

[9] [|http://www.big-bang-theory.com] [10] http://www.windows.ucar.edu/tour/link=/our_solar_system/formation.html [11] http://www.nasa.gov/worldbook/solarsystem_worldbook.html