Universal Census of the Universe

04-Feb-2010: Using data from the NASA/ESA Hubble Space Telescope, astronomers have, for the first time, created a demographic census of galaxy types and shapes from a time before the Earth and the Sun existed, to the present day. The results show that, contrary to contemporary thought, more than half of the present-day spiral galaxies had so-called peculiar shapes only 6 billion years ago, which, if confirmed, highlights the importance of collisions and mergers in the recent past of many galaxies. It also provides clues for the unique status of our own galaxy, the Milky Way.

The results: Some 6 billion years ago, peculiar-shaped galaxies held the majority, at some 52 percent of the galaxy types in the sample. Spirals accounted for only 31 percent. Today, spirals make up some 72 percent of the sample, versus 10 percent for the peculiars. The proportion of the population in each sample accounted for by elliptical galaxies and spiral-elliptical hybrids remained virtually constant.