The relative rotations of the moon and the earth mean that only the one side is ever visible.

However, scientists believe that the impact of a large asteroid hitting the moon could have flipped it around, turning a different side that we now see towards earth.

A study of craters on the far side of the moon suggests that it was hit by a large object around 3.9 billion years ago.

More craters should have been found on the western hemisphere than the eastern side, scientists speculated, because of the way that debris from space currently hits the satellite.

But a study by Mark Wieczorek and Matthieu Le Feuvrem, from the Paris Institute of Earth Physics in France, found the opposite to be true.

The research into the age and location of 46 craters found that there were more older craters on the eastern side.

The findings, reported in New Scientist magazine, suggest that the eastern hemisphere once faced more impact from asteroids than the western side, only possible if the moon faced the other way.

The scientists believe that this could have happened if a large asteroid had caused the moon to begin to turn very slowly for tens of thousands of years until it stopped in the position it is now.

by:telegraph