How Lunar Liquid Mirror Telescopes Work

What Will the Lunar Liquid Mirror Telescope See?

Image of stars and galaxies taken with the 6-meter LMT at the University of British Columbia
Image of stars and galaxies taken with the 6-meter LMT at the University of British Columbia
NASA/Photo by Paul Hickson (University of British Columbia)

A liquid mirror telescope placed on the moon instantly has a major advantage over an earthbound telescope: It's free from atmospheric distortion, which affects celestial images. For the same reason, it's also able to detect more forms of electromagnetic energy. Most types of electromagnetic radiation, except for visible light and radio waves, are absorbed by the Earth's atmosphere. On the moon, which has no atmosphere at all, a telescope would be exposed to the full spectrum of electromagnetic radiation -- gamma rays, X-rays, ultraviolet light, visible light, infrared radiation, microwaves and radio waves.

A telescope using an ionic liquid as its primary mirror would be particularly sensitive to visible light and infrared radiation. This would be important for observing the universe's most distant objects, which are moving rapidly away from the Earth. The Doppler effect causes them to create radiation in the longer-wavelength, infrared portion of the spectrum.

Size is also a key factor. In the low-gravity environment of the moon, it's much easier to build big structures. The team designing the LLMT believes it can build a primary liquid mirror that is 66 feet to 328 feet wide. Such a mirror would be able to observe objects 100 to 1,000 times fainter than the next generation of telescopes -- including the James Webb Space Telescope -- are able to. That means astronomers could use the instrument to peer deeper into space and time than ever before. For the first time, we could be able to detect the very early phases of the universe right after the Big Bang, expanding our understanding of how the newly formed universe behaved.

When Might a Lunar Liquid Mirror Telescope Become a Reality?

Right now, the LLMT is still a concept. The project has received funding from the NASA Institute for Advanced Concepts for a study to show how a telescope on the moon might support astronomy. This is important because the moon is the first target in the Vision for Space Exploration, an initiative seeking how to go out beyond Earth's orbit for purposes of human exploration and scientific discovery. If NASA can demonstrate that lunar outposts would be practical, with both economic and scientific value, then the public -- and ultimately Congress --­ might be willing to show appropriate financial support.

A lunar liquid mirror telescope is among several projects that will help NASA prove the feasibility of space exploration. Even still, the earliest it could be deployed is 2020. Until then, astronomers will have to be satisfied with liquid mirror telescopes, such as the Large Zenith Telescope, that view the heavens from Earth.

To find out more about lunar liquid mirror telescopes, check out the links below.

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  • “The 4-m International Liquid Mirror Telescope Project (ILMT),” by Poels, J., Borra, E., Claeskens, J. F., Jean, C., Manfroid, J., Montfort, F., Moreau, O., Nakos, Th., Surdej, J., Swings, J. P., van Dessel, E., & Vangeyte, B. ASP Conf. Ser., Vol. 238, 2001.
  • “Amazing New Mirror Reflects Ambition for Lunar Telescope,” by Ker Than., June 20, 2007.
  • “Deposition of metal films on an ionic liquid as a basis for a lunar telescope,” by Borra, Ermanno F.; Seddiki, Omar; Angel, Roger; Eisenstein, Daniel; Hickson, Paul; Seddon, Kenneth R.; Worden, Simon P. Nature. Volume 447: June 21, 2007.
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  • "How Things Work Today," Edited by Michael Wright and Mukul Patel, Crown Publishers, New York, 2000.
  • The Hubble Space Telescope Web Site
  • The James Webb Space Telescope Web Site
  • “Liquid mirrors may revolutionize astronomy,” by Michael J. Martin. United Press International, October 12, 2001.
  • “Mirror, Mirror, on the Moon …,” by JR Minkel. Scientific American, June 21, 2007.
  • “NASA Liquid-Mirror Telescope on Moon Might See Deeper Back in Time,” June 21, 2007.
  • "The New York Public Library Science Desk Reference," Edited by Patricia Barnes-Svarney, Macmillan, New York, 1995.
  • “A Plan to Build a Giant Liquid Telescope on the Moon,” by Alexander Gelfand. Wired, May 21, 2007.
  • “Progress made toward lunar liquid mirror telescope,” by Will Dunham. Reuters, June 21, 2007.