Astronomers estimate star temperature from color, spectra, and physical models. Here’s how those measurements work and why they matter.

Learn what a star is, how it produces light, what types exist, and how stars are born, live, and die.

Explore why stars vary in temperature, from mass and fusion rate to color, composition, and life stage.

Learn what scientists mean by the biggest known star, how it’s measured, and which stellar giants top the current list.

Learn how stars stay stable for millions or billions of years through the balance between gravity and internal pressure.

Learn how astronomers use star color to estimate temperature, why blue stars are hotter than red ones, and what other factors affect stellar color.

Learn how massive stars collapse into neutron stars, from core fusion failure to supernova rebound, proto-neutron stars, and pulsars.

Learn how astronomers measure galaxy size using radii, light profiles, redshift, and modern survey data across different galaxy types.

Galaxies preserve clues to cosmic evolution, from the first stars to dark matter. Learn how their light, structure, and motion map the universe’s past.