Liquid Telescopes Expand Ability to See Deep Space
In 1991, Ermanno Borra suggested that a moon telescope using liquid for its mirrors instead of polished glass could offer spectacular insight into deep space viewing. Among the practical and economic advantages, a liquid telescope would have a sensitivity 1,000 times greater than the next generation of conventional telescopes, such as the James Webb Telescope, which plans to launch in 2013.
The idea sounded far-fetched at the time, but in 2004, Borra received funding from the NASA Institute for Advanced Concepts in hopes that the idea would overcome the current limits of telescope technology.
Recently, Borra, a researcher at the Université Laval in Canada, and his colleagues took another significant step toward the realization of such a telescope. They discovered a liquid--and a combination of other materials--that could conceivably withstand the conditions on the moon as well as the ability to function in the infrared range (at temperatures below -140 degrees Celsius).
The key ingredient is an ionic liquid coated with silver, created by a vaporization process for the first time ever. This smooth, highly reflective liquid is poured into a spinning container, where it spreads out to form a thin disk that can be used as a telescope mirror. The mirror, which would have a diameter between 20 and 100 meters, would gather and focus light for enhanced viewing.
Liquid telescopes have been made on the Earth (such as the Large Zenith Telescope in British Columbia, which is the third largest telescope in the world). Unlike heavy glass mirrors, the liquid doesn't need expensive supports to keep it from sagging. However, liquid telescopes on earth are made of mercury, which would freeze on the moon.
A liquid telescope on the moon using Borra's silver-coated ionic liquid, however, is ideal for infrared viewing. (Objects in deep space are red-shifted since they are traveling away from us--and each other--so that the light we receive has longer, infrared wavelengths.) Plus, a telescope on the moon wouldn't have to deal with Earth's gravity or denser atmosphere.
Surprisingly for such an advanced technology, the cost is another advantage, due mainly to less stringent fabrication requirements compared with polished glass.
The researchers say that a liquid lunar telescope is still many years off, if it will ever be built at all. However, with these advantages, and the extraordinary sensitivity, scientists will continue to investigate the possibilities. Until then, the unknown stuff that lies in the far beyond will remain in the dark.
via: Universite Laval