I wasnt surprised when the Fox television network aired a program earlier this year alleging that NASA faked the Apollo Moon missions that took place from 1968 to 1972. This particular conspiracy theory has been around as long as the Apollo program itself, but has had its life breathed anew thanks to this absurd television show.

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Astronomer Phil Plait of Sonoma Statu University authors the website badastronomy.com.

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The conspiracy theorists say they have proof for their beliefs. But their claims reveal tremendous ignorance of science, from the basic principles of photography to geology and physics. For example, the first bit of "proof" usually offered by the conspiracy theorists is the lack of stars in the Apollo images. Its true: nearly every picture taken from lunar orbit and from the Moon's surface shows a jet-black sky, completely devoid of stars. If the Moon has no air, the doubters say, the sky should be filled with stars!

Thats just plain wrong. On the lunar surface the astronauts' cameras were loaded with low-speed film (Ektachrome 64 for color and Panatomic X for black and white) and set to expose for bright sunlightthat is, for a fraction of a second. Even the brightest starswhich are 10,000 times fainter than the full Moon looks from Earth and 10 billion times fainter than the Sunwould require exposures of many seconds. That would have drastically overexposed any scenes of the astronauts, their lander and the Moon itself. A properly exposed photo made on the day side of the Moonjust like one taken here on Earth of a brightly lit playing field at nightwouldn't record any stars.

Furthermore, the astronauts did take some pictures that show stars. On Apollo 16, for example, John Young used a small ultraviolet telescope, placed in the shadow of the lunar module, to photograph distant stars and galaxies. And on several Apollo missions the orbiting command module pilots, while flying over the Moon's night side, photographed the stars and the faint solar corona, using ultrahigh-speed film and long exposures.

The conspiracy theorists look at the hours and hours of video transmissions sent back from the Moon, much of it in color and of very good clarity, and see in it evidence of fakery. Actually, its that very footage which proves men did walk on the Moon. When the astronauts booted feet hit the surface, the loose lunar soil sprayed up. In the vacuum environment, the dust particles act like little cannonballs, following a ballistic trajectory perfect parabolas that take them up and directly back down. If this had been faked in a Nevada film studio, as the conspiracy theorists claim, the extremely fine-grain dust would have billowed up, supported by the Earths thick atmosphere. Ironically, even though the Moons gravity is only one-sixth that of the Earth, the dust falls faster because there is no air to keep it aloft. Therefore, the only way this footage could have been taken was in a low gravity vacuum environment. For comparison, the 1968 movie, 2001: A Space Odyssey is Hollywood's best portrayal of spaceflight on film made during the Apollo era -- but it doesn't come close to portraying the visual characteristics of a Moonwalk accurately.