Stars and galaxies
Once enough matter is collected, gravity becomes the dominant organizer. It creates stars, stellar systems, galaxies and larger structures.
Star formationDense regions of gas collapse under gravity and can form protostars.
Stellar evolutionNuclear reactions support long-lived stars; mass strongly influences their later evolution.
ElementsStars and related high-energy processes produce many of the chemical elements found in planets and life.
GalaxiesStars, gas, dust and other components form enormous gravitationally bound systems.
Compact objectsWhite dwarfs, neutron stars and relativistic collapse probe matter and gravity under extreme conditions.