Quirks & Quarks

Super spiral galaxies are beautiful giants

Spiral galaxies were thought to be limited in size, but astronomers have discovered rare examples more than ten times the size of the Milky Way.

Astronomers discover improbably large spiral galaxies

Super spiral galaxies from the Sloan Digital Sky Survey (NASA/SDSS)
Most galaxies in the universe are small - by cosmological standards - and, like our Milky Way galaxy, have attractive delicate spiral structures. Until now, the large galaxies that astronomers have discovered, on the other hand, have been what are known as elliptical galaxies - which are unstructured jumbles of stars.

Astronomers had thought, in fact, that this had to be the case, and that spiral galaxies can't grow big, and that elliptical galaxies were formed from smaller galaxies crashing together and chaotically mixing.

Dr. Patrick Ogle, an astrophysicist with the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, has found a new, rare kind of "super spiral" galaxy - ten times the size of our galaxy - that seems to form from mergers, but somehow forms new spiral arms. Theorists will now have to determine just how this kind of galactic collision can happen.

Related Links

- Paper in the Astrophysical Journal
- NASA Jet Propulsion Lab release
Sky and Telescope story
Scientific American story