Dr. Terry Bridges, an astronomer at Queen’s University, has discovered that as many as one quarter of the star clusters in our Milky Way are invaders from other galaxies.
The study – co-authored by Duncan Forbes of Swinburne University of Technology in Australia – was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society, and has fascinated even lay persons with his revelation that entire star clusters have “drifted” from one galaxy to another; cross-pollination or cross-breeding on a macro level.
And Dr. Bridges may have an ally, or at least a supporter, in the form of current Queen’s University Principal Daniel Woolfe, who – based on a recent Twitter post, where he referenced a Star Trek episode from the original series – just may be a bit of a Trekker…
The study also theorizes there may be as many as six dwarf galaxies yet to be discovered within the Milky Way, instead of only the two that have been 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 have made their way into our galaxy over the last few billion years,” says Dr. Terry Bridges.
Astronomers had previously 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.
But utilizing Hubble Space Telescope data, Dr. Bridges and Dr. Forbes examined old star clusters within the Milky Way galaxy. From that research they were able to compile the largest ever high-quality database to record the age and chemical properties of each of these clusters.
Bridges confirmed their endeavor required looking at all the data they could find; the best of which was from the Hubble due to its impressive imaging capabilities.
“We looked at the ages and the amounts of heavy elements in these clusters, which can be measured from their stars.”
The researchers’ work also suggests that the Milky Way may have swallowed-up more dwarf galaxies than was previously believed. They found that many of the foreign clusters originally existed within dwarf galaxies, which are small galaxies of up to 100 million stars that sit within our much larger Milky Way.