Cosmic

Proposed Origin: The observable universe evolved from an early hot, extremely dense state.

This pre-origin theory is acceptable for ΛCDM cosmology. But if tied to metaphysics, it should be separated.

The Big Bang Theory

The start of cosmic expansion

Energy/particle epochs: fractions of a second onward

Atoms (recombination): ~13.7996 BYA

Cosmic Dark Ages: ~13.8 to ~13.6 BYA

First stars form: ~13.6–13.7 BYA

Ignition of First stars (Pop III): Population III stars remain theoretical unobserved despite strong indirect evidence.

Reionization begins: the ultraviolet light from early stars ionizes hydrogen.

First galaxies:  Forms from dark matter halos.

Galaxies grow: Through mergers and star formation.

First generations of stars: Synthesis of heavy elements (carbon, oxygen, iron) via nuclear fusion and supernovae. 

Heavy elements: Seed future planetary systems.

The Milky Way: Forms and evolves during this period.

Star formation rate: Peaks and then declines.

Spiral galaxies (like Milky Way): Develop stable structures.

Multiple generations of stars: Enriched interstellar space with metals. Conditions for rocky planets become common.

Solar system forms: ~4.57 BYA → 

• A region of the Milky Way collapses into a protoplanetary disk. 

• The Sun ignites at the center. 

• Planets, moons, asteroids, and comets form from remaining material.

Earth forms: ~4.54 BYA

Earth accretion and differentiation

Magma oceans and intense volcanism

Heavy meteoritic bombardment

Moon formation

Early atmosphere from outgassing

Evidence of liquid water (zircons)

Zircon crystals and meteorites as primary evidence