| Abstract: | Soon after the discovery of the expansion of the universe, astronomers hoped to determine the parameters of the universe by
comparing distant galaxies with nearby ones. Observing distant galaxies, however, meant observing them as they were long ago.
A crucial assumption in these studies was that galaxies hardly change, in the time scale of the expansion of the universe.
Beatrice Tinsley was one of the first astronomers to point out that galaxies do change. Here we discuss a simplified model
of galactic evolution, and show that the comparison of its prediction with observations uncovers clues to how galaxies evolve
with time |
