A Summary of the History of the Universe

Time from Big Bang	Temperature/K	Nature of Universe
	Infinite	Infinitesimally small, infinitely dense. There is believed to be only one unified force, with the fundamental forces we know today acting as one force. The laws of physics are unknown before this point
		The era of inflation. The Universe expands by a factor of aroundtimes in volume.
		The fundamental forces have separated from the single unified force and are now distinct.
		All particles – quarks and leptons included – exist in a soup, with no two particles in combination.
		Quarks combine to form neutrons and protons.
		Nuclei start to form.
years		Atoms start to form as electrons combine with nuclei. The universe becomes transparent to electromagnetic radiation, which can now move freely through space as photons.
years to present	declining to 2.7	Stars, galaxies and planets form. The whole history of the Universe has been one of expansion, with all parts of the Universe receding from all other parts.