Galaxies Die from the Inside Out

When the first stars and galaxies started to form, it was like a spark of a massive chain reaction where the vast amounts of gas and dust that had clumped together were quickly converted into dense, luminous star clusters. ┬áThis was the beginning of the formation of the heavier elements that would eventually make up all that we see on the planet Earth. ┬áBut when did this massive tirade of star formation end? When we look at galaxies in the present epoch, most don’t form stars very rapidly at all, and giant elliptical galaxies are all but devoid of gas,...