It was a fake right?

Myth: The US flag deployed by Aldrin and Armstrong is waving in a breeze, thus proving that the astronauts were in a studio on Earth, and not on the Moon.

Fact: The flag was a dreadful design. Its uppermost edge was held rigid by a horizontal pole, which swivelled too easily at the point where it met the vertical mast. When the astronauts deployed the flag, it did wave about for quite a while, but this was residual momentum from contact with the astronauts - not the product of windy weather. In fact, that lack of wind resistance is precisely why the flag continued to drift back and forth for so long.

Crate expectations

Myth: There should have been a freshly gouged crater where the Lunar Module's descent engine blasted into the lunar soil.

Fact: The fine, powdery soil was disturbed by the downward-pointing jet of the exhaust, but the thrust was not sufficiently concentrated to gouge a crater in the topsoil, let alone its hard rocky substrate. In the vacuum of space, the LM's rocket exhaust splayed out sideways almost as soon as it escaped the engine's bell-shaped nozzle. The plume's impact on the Moon's surface was broad rather than focused.

A soft landing

Myth: There should be lots of kicked-up dust on the footpads, and on the LM generally.

Fact: Armstrong made a gentle touchdown. There is little dust because any disturbed grains of soil would have travelled some distance sideways before settling on the ground. There is no air on the Moon to slow them down. Two years later, Apollo 15's LM Falcon had a much rougher ride. Laden with extra equipment, they came down with a bump that rattled everything inside. Falcon's footpads dug deeper into the soil than the Eagle's.

Just look at those stars!

Myth: Countless stars should be visible in the black and airless lunar sky, yet there's not so much as a single speck.

Fact: An astronaut in a white spacesuit in bright sunlight needs an exposure of only a few fractions of a second, but stars are too distant and dim to register on normal photographic film unless very long exposure times are used. That's also why shuttles and space stations photographed in orbit appear against the same pure black sky.

Time and again, space travellers tell of the vast swathes of stars they can see, yet those stars never appear on their photos. Instruments such as the Hubble Space Telescope, directed towards stars and galaxies, often work with exposures lasting for hours, or even days.

Light trickery?

Myth: There should only be one concentrated and highly directional source of light in the pictures - the Sun - but many of the shots look as if they were snapped using broader and softer illumination. The harsh sunlight should create dazzling highlights opposed by pure black shadows, with no subtle shading; yet in most of the shots the astronauts seem softly lit. The shadows look as if they have been filled in by lights.

Fact: The astronauts are standing on a gigantic, bright, grey-white photographic reflector. It bounces a great deal of sunlight back into space. Photographers often use big reflector panels to 'fill in' shadow areas, especially when the Sun is bright, and the contrast range of the natural lighting is too wide for cameras. On the Moon, the astronauts are lit similarly, but by natural surroundings, not studio technicians.

My moon shadow and me

Myth: The shadows in the photographs sprawl off in different directions, suggesting multiple light sources, as in a studio.

Fact: Most of the photos were taken with wide-angle Hasselblad cameras. Multiple 'vanishing points' are inevitable in such shots.

Last word

And if none of this settles your argument with the conspiracy theorist sitting next to you at your next dinner party, point out that... Radio observers on Earth routinely timed and triangulated the signals from the Moon. Russia would have alerted the world if the radio data had seemed odd. And why would they fake it nine times, anyway?