A powerful telescope built on the Moon is one step closer, say scientists, whose work could be used to develop a liquid mirror that would not break during the journey from Earth.

A team led by physicist Dr Ermanno Borra, of the Universite Laval in Quebec, Canada report their work in today's issue of the journal Nature.

Enter an idea that has been kicked around for more than a century and a half - the liquid mirror telescope.

The idea is that mercury is gently spun on a round table, so that centrifugal force combined with gravity forces the quicksilver to spread out, with its edges thicker than its centre.

The parabolic shape is exactly what is needed to focus the reflected light on a detector, and supporters say the optical qualities are as good as with glass.