Milky Way’s ‘twin’ discovered

Astronomers have for the first time found other groups of galaxies that are just like ours.

While the Milky Way is a fairly typical galaxy on its own, when paired with its close neighbours – the Magellanic Clouds – it’s very unusual, and could even have been one of a kind.

But Dr Aaron Robotham of the International Centre for Radio Astronomy Research (ICRAR) and the University of St Andrews in Scotland, says he’s found two more in the most detailed map of the local universe yet, the Galaxy and Mass Assembly survey (GAMA).

“We’ve never found another galaxy system like the Milky Way before, which is not surprising, considering how hard they are to spot! It’s only recently become possible to do the type of analysis that lets us find similar groups,” says Dr Robotham.

Sophisticated simulations predict that galaxy systems similar to our own are quite a rare occurrence.

“We found about three percent of galaxies similar to the Milky Way have companion galaxies like the Magellanic Clouds, which is very rare indeed. In total we found 14 galaxy systems that are similar to ours, with two of those being an almost exact match,” says Robotham.

While many galaxies have smaller galaxies in orbit around them, few have two that are as large as the Magellanic Clouds.

Dr Robotham’s work also found that although companions like the Magellanic Clouds are rare, when they are found it’s usually near a galaxy very like the Milky Way.

“The galaxy we live in is perfectly typical, but the nearby Magellenic Clouds are a rare, and possibly short-lived, occurrence. We should enjoy them whilst we can – they’ll only be around for a few billion more years,” says Robotham.