- The tilted orbit of the moon means some craters at its poles are always shaded
- These act as 'cold traps' and provide the perfect environment for frozen water
- Even so, only 3.5 per cent of the moon's shadowed areas feature frozen water
- The same phenomenon could also occur on Mercury and the dwarf planet Ceres
- The finding could mean future lunar colonies could harvest water on the moon
- They could also convert it into hydrogen and oxygen for rocket fuel or oxygen