Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
Liquid Mirror Telescope For Moon Studied By NASA
A Lunar Liquid Mirror Telescope (LLMT) is under study thanks to a grant from NASA. J. Roger Angel, a regents professor at the University of Arizona, is leading a project to study the feasibility of a 100 meter LLMT at the moon's south pole.
Why liquid mirrors? Ever since 1668, when Isaac Newton built the first reflector telescope with a one-inch diameter mirror made of metal, astronomers have longed for bigger parabolic mirrors. Opticians expend a great deal of effort to grind larger and larger pieces of glass to just this shape.
Liquid Mirror Telescopes were first talked about several hundred years ago. Imagine a bowl of mercury at the center of a lazy susan. When you give it a spin, the surface of the liquid forms that highly prized shape - a parabola. The bigger the bowl, the bigger the resulting mirror.
The first serious attempts to actually build a LMT took place in the early twentieth century. Robert W. Wood, a physicist at Johns Hopkins University, built a working telescope, but could not accurately control the speed of the turntable, resulting in a mirror with a variable focal length. (The rotation must be controlled to less than one part in 100,000 during exposure.) Pictures of star trails were focused in some places, but blurry in others.
(The Large Zenith Telescope mirror)
The LMT concept has been made to work. The Large Zenith Telescope at the University of British Columbia uses a 6-meter mirror, making it the third largest optical telescope in North America. It was built at a cost of approximately $1 million. A telescope with a conventional glass mirror of the same size would cost $100 million.
It is hoped that similar savings might apply when constructing telescopes on the moon. In addition, the moon is completely free from atmospheric absorptions and distortion.
The only disadvantage of the LMT is that you cannot tilt it; it must remain perpendicular to the local gravitational field. You can only use it to look at what is directly above the telescope; however, a mirror of this size could take a very penetrating look at its patch of sky.
"You would be seeing things farther back in time than anyone has ever seen any galaxy or star or quasar," [Angel] explained. "It could give you a chance to see what was happening at a very early time."
(From J. Roger Angel and the LLMT)
Obviously, for such a project to be attempted, there would need to be substantial infrastructure already im place on the moon. As Dr. Angel remarked, "You could not justify that kind of infrastructure (just) to build this kind of telescope, but if the infrastructure already were there, this is something that looks feasible to do."
There is a very early reference to a large liquid mirror telescope in science fiction; but this LMT is on Mars, not the moon. In his excellent 1934 novella Old Faithful, author Raymond Z. Gallun writes about a Martian named 774, who has a desperate need to contact Earth:
Piercing the dome, opposite the upper end of the cylinder, was a circular opening through which a portion of the starlit sky was visible; and at the base of the cylinder a great bowl rotated rapidly, like a huge wheel... The bowl contained mercury. As the container spun on its perfectly balanced axis, centrifugal force caused the mercury to spread in a thin, precisely distributed layer over the inside of the bowl, forming a concave surface that acted admirably as a mirror for Number 774's gigantic reflecting telescope. It's area, and its consequent light-gathering capacity, was many times greater than any rigid mirror that could have been constructed without flaws.
(Gallun appears to err in his use of the LMT; read more about the Martian LMT)
Read more about J. Roger Angel and the LLMT, read more about LMTs at Space.com or take a look at the Large Zenith Telescope. Thanks to Winchell Chung for the tip and the sf for this story.
Scroll down for more stories in the same category. (Story submitted 2/5/2006)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 23 )
Related News Stories - (" Space Tech ")
Will Space Stations Have Large Interior Spaces Again?
'They filed clumsily into the battleroom, like children in a swimming pool for the first time, clinging to the handholds along the side.' - Orson Scott Card, 1985.
Reflect Orbital Offers 'Sunlight on Demand' And Light Pollution
'I don't have to tell you about the seven two-mile-diameter orbital mirrors...'
Chrysalis Generation Ship to Alpha Centauri
'This was their world, their planet —
this swift-traveling, yet seemingly moveless vessel.' - Nat Schachner, 1934
The First Space Warship For Space Force
'Each of the electrical ships carried about twenty men...' - Garrett P. Serviss, 1898.
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
Golf Ball Test Robot Wears Them Out
"The robot solemnly hit a ball against the wall, picked it up and teed it, hit it again, over and again...'
Boring Company Vegas Loop Like Asimov Said
'There was a wall ahead... It was riddled with holes that were the mouths of tunnels.'
Rigid Metallic Clothing From Science Fiction To You
'...support the interior human structure against Jupiter’s pull.'
Is The Seattle Ultrasonics C-200 A Heinlein Vibroblade?
'It ain't a vibroblade. It's steel. Messy.'
Roborock Saros Z70 Is A Robot Vacuum With An Arm
'Anything larger than a BB shot it picked up and placed in a tray...'
A Beautiful Visualization Of Compact Food
'The German chemists have discovered how to supply the needed elements in compact, undiluted form...'
Bone-Building Drug Evenity Approved
'Compounds devised by the biochemists for the rapid building of bone...'
Secret Kill Switch Found In Yutong Buses
'The car faltered as the external command came to brake...'
Inmotion Electric Unicycle In Combat
'It is about the size and shape of a kitchen stool, gyro-stabilized...'
Grok Scores Best In Psychological Tests
'Try to find out how he ticks...'
PaXini Supersensitive Robot Fingers
'My fingers are not that sensitive...'
Congress Considers Automatic Emergency Braking, One Hundred Years Too Late
'The greatest problem of all was the elimination of the human element of braking together with its inevitable time lag.'
The Desert Ship Sailed In Imagination
'Across the ancient sea floor a dozen tall, blue-sailed Martian sand ships floated, like blue smoke.'
The Zapata Air Scooter Would Be Great In A Science Fiction Story
'Betty's slapdash style.'
Thermostabilized Wet Meat Product (NASA Prototype)
There are no orbiting Michelin stars. Yet.
Could Crystal Batteries Generate Power For Centuries?
'Power could be compressed thus into an inch-square cube of what looked like blue-white ice'
