Standard Big Bang Cosmology

• Sometime in the distant past there was nothing – space and time did not exist

• Vacuum fluctuations created a singularity that was very hot and dense

• The Universe expanded from this singularity

• As it expanded, it cooled

• Photons became quarks
• Quarks became neutrons and protons
• Neutrons and protons made atoms
• Atoms clumped together to make stars and galaxies