Cosmology and the Early Universe

Concepts describing the origin, large-scale structure and composition of the universe as a whole: the Big Bang theory and the cosmic inflation thought to have preceded it, the cosmic microwave background radiation left over from that early hot state, the cosmological constant, dark energy and dark matter that dominate the universe's present-day mass and expansion, the redshift used to measure the recession of distant galaxies, and Olbers' paradox about the darkness of the night sky. Belongs here: a concept about the universe's origin, expansion or overall composition. Does not belong here: a concept about a single spacecraft maneuver or orbit, grouped under Orbital Mechanics and Spaceflight Engineering, or a concept about extraterrestrial life, grouped under Astrobiology and the Search for Life.