New 'Alien Invader' Star Clusters Found in Milky Way

02-27-2010 • sciencedaily.com

As many as one quarter of the star clusters in our Milky Way -- many more than previously thought -- are invaders from other galaxies, according to a new study. The report also suggests there may be as many as six dwarf galaxies yet to be discovered within the Milky Way rather than the two that were previously confirmed. "Some of the stars and star clusters you see when you look into space at night are aliens from another galaxy, just not the green-skinned type you find in a Hollywood movie. These 'alien' star clusters that have made their way into our galaxy over the last few billion years," says Terry Bridges, an astronomer at Queen's University in Kingston, Canada. The study (co-authored by Duncan Forbes of Swinburne University of Technology in Australia) has been accepted for publication in the Monthly Notices of the Royal Astronomical Society. Previously, astronomers had suspected that some star clusters, which contain from 100,000 to a million stars each, were foreign to our galaxy, but it was difficult to identify which ones.