Problem neighbours: The galaxies that are so close, they play havoc with each other's structure - 25th Apr 2011

These two neighbouring spiral galaxies were discovered by the English astronomer William Herschel in 1783.

More than 700million light-years away from Earth in the constellation of Sextans, NGC 3169 and NGC 3166 sit extremely close together.

Now scientists at the European Space Observatory have gauged the distance between them as a mere 50,000 light-years.

While this might seem a huge distance, it is equal to just half the diametre of our own Milky Way.

In comparison, the nearest spiral galaxy of the Milky Way is Andromeda, which sits 2.5million light-years away.

And, in such tight quarters, gravity can start to play havoc with galactic structure.

Spiral galaxies tend to have orderly swirls of stars and dust rotating about their glowing centres. Read More