Andromeda is the most distant thing visible with the naked eye. M31 or the Great Nebula in the constellation of Andromeda, as it is also known is, along with the Milky Way, one of the largest members of the Local Group of galaxies. There are a few dozen members of the local group, but recent observations by an international team led by Mike Irwin of Cambridge University suggests there used to be a few more – and there is at least one new victim ready to be sucked into Andromeda’s fatal embrace.
Using the Canada-France-Hawaii telescope on Mauna Kea, Hawaii, the astronomers created the largest and deepest panorama of a galaxy ever made. In it, the wisps and knots of stars torn from other galaxies could be seen at the edges of Andromeda – the remains of previous galaxies that have interacted with M31. These areas of increased stellar density occur in areas where there is not sufficient dust and gas to create the stars in situ, they have to come from external sources. Our own Milky Way has also interacted with other galaxies – the Small and Large Magellanic clouds are two such objects in the middle of getting sucked in. The Milky Way itself is also on course for a meeting with Andromeda, but as we’re still 2.5 million light years from one another, no need to look for a new neighbourhood soon.
Slightly closer to Andromeda, the Triangulum galaxy, or M33, is showing signs of interacting with the larger body. It seems that by the time Andromeda hits us, it may have grown a little from feasting on that galaxy’s stellar population.