Constituents of a Galaxy

The budged of ordinary (i.e., baryonic) matter in the Universe and within galaxies, as a function of cosmic time. As cosmic time increases, the amount of baryons in galaxies grows. Inside galaxies, the initial gas-dominated phase changes towards a stellar mass-dominated regime observed today. Use the scrollbar to see how these changes occur throughout cosmic history.

All baryons

Baryons within galaxies

Move the slider to select a particular cosmic age
  • baryons in galaxy
  • stars
  • atomic + molecular gas
  • atomic gas
  • molecular gas