Galaxies the way they were
Wednesday, April 3, 2013 - 07:30
in Astronomy & Space
(Phys.org) —Galaxies today come very roughly in two types: reddish, elliptically shaped collections of older stars, and bluer, spiral shaped objects dominated by young stars. The conventional wisdom is that the two types are related to one another, ellipticals representing an older, more evolved stage of galaxies. Astronomers have discovered during the past decade that these two categories seem also to apply to galaxies in the early universe. In particular, galaxies so distant from us that their light has been traveling for about eleven and one-half billion years, 84% of the age of the universe, also generally fall into these two groups.