Oldest Spiral Galaxy DiscoveredCategory: Science & Technology
Posted: July 20, 2012 04:44AM
A quick look through the image archives for the Hubble Space Telescope reveals a variety of different structures to galaxies. Primarily you will find massive elliptical galaxies and more elegant spiral and barred-spiral galaxies, but there are also a number of unusual galaxies whose structures have been disrupted by recent collisions. All of these galaxies are relatively young galaxies, as it takes time for those structures to develop, but researchers have just found a spiral galaxy from when the Universe was only three billion years old.
Named BX442, the spiral galaxy was found by astronomers in part from the University of California, Los Angeles with Hubble while examining 300 galaxies at about the same distance. Upon finding this galaxy the researchers turned to the W.M. Keck Observatory to collect spectroscopic information which proves it is indeed a single galaxy, and not two. It is large enough to have been multiple galaxies though as only 30 other galaxies in this survey weigh as much.
The researchers now have to figure out how this galaxy got its spiral. Current cosmological theory would say this structure should either not exist or be very unlikely to form that far in the past. The current suggestion by the astronomers are that it formed from the collision of a great many smaller galaxies, and this idea is aided by the presence of a dwarf galaxy also visible in the image. BX442 will definitely be studied more as it provides a link between the primitive galaxies and the younger ones we are more familiar with.