01
Cosmic Expansion
On sufficiently large scales, the Universe is expanding. The observed recession of distant galaxies is described within general-relativistic cosmological models rather than as ordinary motion through static space.
v ≈ H₀d
02
Cosmic Microwave Background
The cosmic microwave background is relic electromagnetic radiation from the early Universe, observed today at microwave wavelengths after cosmic expansion cooled and redshifted it.
03
Cosmic Composition
Modern cosmological models attribute the majority of the Universe's mass-energy budget to dark matter and dark energy, with ordinary baryonic matter forming a comparatively small fraction.
04
Early Universe
- Early hot dense plasma.
- Primordial nucleosynthesis.
- Recombination and photon decoupling.
- Formation of the first stars.
- Growth of galaxies and large-scale structure.