origin of the observable universe ~13.8 billion years ago
initial state of extreme density and temperature, expanding and cooling ever since
first seconds: quarks, leptons, photons; first minutes: hydrogen, helium nucleosynthesis
cosmic microwave background radiation: snapshot of the universe at 380,000 years
expansion governed by gravity, dark matter, dark energy
stars formed from hydrogen clouds, nucleosynthesis forged heavier elements up to iron
galaxies, clusters, cosmic web: large-scale structure emerged from quantum fluctuations
the arrow of time and entropy originate here
link to cosmology: the study of the universe's origin, structure, and fate
all geological time, all biology, all civilization trace back to this singular event