By Ron Cowen
Once a cannibal, always a cannibal.
A new survey is adding to the evidence that Andromeda, the Milky Way’s sister galaxy, has not only grown bigger in the past by feasting on smaller galaxies, but is continuing to do so.
In constructing one of the most detailed images of the large spiral galaxy and a wide region around it, Mike J. Irwin of the University of Cambridge in England and his colleagues found 14 previously unknown globular clusters surrounding Andromeda. These groupings of hundreds of thousands of ancient stars all lie far from Andromeda’s disk. Astronomers have theorized that globular clusters, which are common at the outskirts of large galaxies, are remnants of small galaxies devoured long ago.