Era	Epoch	Time after Big Bang	Major Events / Physical Processes
Radiation Era	Planck Epoch	0 – 10⁻⁴³ s	Quantum gravity dominates; laws of physics not yet unified.
	Grand Unified Epoch	10⁻⁴³ – 10⁻³⁶ s	Strong force separates from electroweak force.
	Inflationary Epoch	10⁻³⁶ – 10⁻³² s	Universe undergoes exponential expansion; seeds of structure formed.
	Electroweak Epoch	10⁻³² – 10⁻¹² s	Electromagnetic and weak forces separate.
	Quark Epoch	10⁻¹² – 10⁻⁶ s	Universe filled with quarks, leptons, and gauge bosons.
	Hadron Epoch	10⁻⁶ – 1 s	Quarks combine to form protons and neutrons.
	Lepton Epoch	1 – 10 s	Leptons dominate; annihilations of particle-antiparticle pairs occur.
	Nuclear (Nucleosynthesis) Epoch	3 – 20 min	Formation of light nuclei (H, He, Li).
Matter Era	Atomic Epoch	~380,000 years	Recombination occurs; neutral atoms form; Cosmic Microwave Background released.
	Galactic Epoch	~200 million years	First galaxies form; large-scale structure begins.
	Stellar Epoch	~400 million years onward	First stars form; reionization begins; galaxies evolve.
Dark Energy Era	Present Epoch	~9.8 billion years onward	Dark energy dominates expansion; accelerated expansion; universe structure develops.
	Future Epochs	Future	Possible fates include continued expansion, heat death, or other scenarios depending on cosmological models.