A liquid reflector for a vast Newtonian telescope to be based on the surface of the Moon is being developed by scientists in Canada, UK, and US. The new type of telescope could provide the clearest views yet of ancient parts of the universe and will use a convex layer of an ionic liquid coated with silver. Earth-bound liquid reflectors have used mercury, but mercury would simply boil in the low-vacuum conditions on the Moon, moreover it would be dangerous and cumbersome to take to the Moon in the necessary quantities. An ionic liquid mirror the size of a football field on the Moon is not entirely implausible although the team led by Arizona scientist Roger Angel do not expect to be able to implement their plans until at least the year 2020.
Lunar liquid telescope