Canadian researchers have developed a liquid mirror that could operate in a future telescope located on the moon, allowing researchers to peer back into the origins of the universe with extraordinary clarity. Telescopes relying on liquid mirrors can be hundreds of times more powerful than those with glass mirrors--for the same cost--and they should be easier to assemble in space.liquid-mirror telescope could reveal much fainter objects than the Hubble Telescope can, says Ermanno F. Borra, a physics professor at the Université Laval, in Quebec, who is leading the development of the new mirror. The power of a telescope is proportional to the surface area of its mirror. The James Webb telescope, which is scheduled to launch in 2013 and is far more powerful than the Hubble, has a diameter of about six meters. (See "Giant Mirror for a New Space Telescope.") A lunar liquid-mirror telescope could be as large as 20 to 100 meters, says Borra.
The liquid mirror, which was funded by NASA, consists of a pool of an ionic liquid coated with a film of silver. Such ionic liquids are carbon-containing salts that freeze only at very low temperatures and have very high viscosity. The salt used in the Laval mirror is liquid down to -150 ºC and does not evaporate below room temperature, even in a vacuum--suggesting that it could withstand the harsh environment of the moon.
There are two limitations on cosmologists' observations of the early universe: "The objects you want to observe are incredibly distant and incredibly faint," says Borra. Telescopes in orbit like the Hubble, whose views are unobstructed by Earth's atmosphere, are limited in size and power; telescopes on Earth can be larger and more powerful but produce fuzzier images because of the atmosphere. Liquid mirrors couldn't go into orbit, but they could operate on the moon, which has no atmosphere.
0 comments:
Post a Comment