Article Posted on : - Aug 26, 2012

A University of Western Australia/Dr Aaron Robotham photo.

WASHINGTON (PTI): For the first time, astronomers have discovered two far-flung galaxies that are a near-perfect match of our own Milky Way.

Spiral galaxies like the Milky Way are common throughout the Universe, but the newfound "twins" share other key features as well.

For example, both have satellite galaxies very similar to the Milky Way's neighbouring Large and Small Magellanic Clouds, researchers said.

The Milky Way is a fairly typical galaxy on its own, but when paired with its close neighbours, the Magellanic Clouds - it is very rare, and could have been one of a kind.

Astronomer Dr Aaron Robotham, from the University of Western Australia searched for groups of galaxies similar to ours in the most detailed map of the local Universe yet.

"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," said Robotham.

Astronomers haven't been able to tell just how rare until now, with the discovery of not just one but two exact matches amongst the hundreds of thousands of galaxies surveyed.

"We found about 3 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," said Dr. Robotham.

The Milky Way is locked in a complex cosmic dance with its close companions - the Large and Small Magellanic Clouds, which are clearly visible in the southern hemisphere night sky. Many galaxies have smaller galaxies in orbit around them, but few have two that are as large as the Magellanic Clouds.

Robotham's work also found that although companions like the Magellanic Clouds are rare, when they are found they're usually near a galaxy very like the Milky Way, meaning we're in just the right place at the right time to have such a great view in our night sky.

Robotham and colleagues have been awarded further time on telescopes in New South Wales and Chile to study these Milky Way twin systems now that they've been found.

The discovery was reported at the International Astronomical Union General Assembly in Beijing.