Having the infrared data from Spitzer allows us to measure the star formation rates very accurately because we are no longer blinded by dust.
This is an exceptional period of time for astronomy, because for the first time we are able to combine data from almost all of the important wavelengths.
We are finding that mergers do not appear to play the dominant role in star formation, because we see normal-looking, undisturbed galaxies that are undergoing large amounts of star formation.
We have now been able to track star formation in galaxies out to modest distances, more than half the age of the universe, and we find that all galaxies, big or small, seem to be fading gradually so that they are less active today than they were further back in time.
