Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing "Hoax" - Philip Plait (2002)

Part IV. Artificial Intelligence

People believe weird things.

There are people who believe the Earth is 6,000 years old. Some people believe that others can talk to the dead, that a horoscope can accurately guide your day, and that aliens are abducting as many as 800,000 people a year.

I believe weird things, too. I believe that a star can collapse, disappearing from the universe altogether. I believe that the universe itself started as a Big Bang, possibly as a leak in space and time from another, older universe. I believe that there is a vast reservoir of hundred-kilometer-wide chunks of ice hundreds of billions of kilometers out from the Sun, yet I have never seen one of these chunks in situ, nor has any other person on Earth.

So, what's the difference? Why do I think it's wrong to believe that the Earth is young when I believe in things I've never seen?

It's because I have evidence for my beliefs. I can point to welldocumented, rational, reproducible observations and experiments that bolster my confidence in my conclusions. The examples in the second paragraph above are not similarly supported. The people who believe in such things will bring out piles of evidence, certainly, but it's written on tissue paper. A solid cross-examination of the evidence finds it flimsy, fragile, and sometimes even fabricated. The experiments rely on hearsay, or secondhand information, or bad statistics, or a nonreproducible event. Such evidence does not ably support a belief system. And it's definitely not science.

This section has several chapters that deal with pseudoscience, ideas that sound superficially like science, but aren't anything of the sort. The difference between science and pseudoscience is that science is repeatable, and makes specific predictions that can be tested, while pseudoscience generally relies on single, unrepeated events or predictions that are impossible to test. Of all the forms of bad astronomy, pseudoscience is the most pernicious. You might laugh at some of the attitudes presented; how could a modern person believe that NASA never sent men to the moon? Why would someone think that a fuzzy photo of a piece of ice floating outside a Space Shuttle window is evidence of an alien war with humans?

Odds are that you believe NASA sent men to the Moon. So why devote a whole chapter to the minority that doesn't? There are several reasons. The most important is to simply provide a rational and reasoned voice when such a voice is hard to find. People who promote pseudoscience sometimes use astronomy, twisting it beyond recognition, and it can be difficult even for astronomers to understand where the arguments go wrong, let alone someone who is not educated in astronomy.

Also, without an opposing voice, a given hoax (and other matters of pseudoscience) can become endemic. Sure, the true believers will never listen to someone like me, but for every one true believer there are perhaps ten others who want to know the truth-call them passive believers-but who are only hearing one side of the story. They need to hear the other side, science's side, and that's what I present here.

I receive letters all the time from people who initially believed or at least questioned the claims of a pseudoscientist, but upon reading a rational rebuttal realized the pseudoscientist was wrong. I have hope that rational thinking will win in the end, largely because science produces reliable results. Carl Sagan put it best: "Science is a way to not fool ourselves."

So let's take a look at who's fooling whom.

Chapter 17. Appalled at Apollo: Uncovering the Moon-Landing Hoax

t's an engaging story, and almost plausible.

NASA is in trouble. Contractors on the upcoming space mission were negligent, and made a mistake on one of the parts they were building. The mistake was discovered too late, and the part is already integrated with the rocket. They know the part will fail, ending the mission in catastrophe, so they tell NASA. However, NASA officials are under intense public pressure for a successful launch. They know that if they admit there is a problem, the space program (and therefore their paychecks) will grind to a halt. So they decide to launch anyway, knowing the mission will fail.

But the rocket they launch is a dummy, with no one on board. The real astronauts are spirited away to the Nevada desert to a hastily assembled movie set. Under physical threat, the astronauts are forced to obey the NASA officials, faking the entire mission. What they don't know is that NASA plans on murdering them to protect the secret, then claim that astronaut error killed them upon reentry. NASA officials would take a hit but eventually would be exonerated.

Does this scenario sound believable? It does to some people. The story certainly interested Warner Brothers, which made this script into the movie Capricorn One in 1978. It's a pretty good movie, actually, and stars the unlikely group of Eliot Gould, James Brolin, and none other than O. J. Simpson. But remember, it's just a movie. It's not real.

Or was it? Despite what the vast majority of the human population believes, some hold that the movie was portraying reality. NASA faked the whole Apollo Moon project, they claim, and instead of its being the most incredible technical achievement of all time, it is actually the greatest fraud perpetrated on mankind. They believe the fraud continues today.

Surprisingly, there appears to be a market for such a belief. James Oberg, an expert on space travel and its history, estimates that there may be 10 to 25 million people in the United States alone who at least have doubts that NASA sent men to the Moon. This number may be about right-a 1999 Gallup poll found that 6 percent of Americans, or about 12 million people, believe the NASA conspiracy theory, the same number found in a 1995 Timel CNN poll. Executives at the Fox Television network thought enough people would be interested in this idea that in 2001 they aired a one-hour program about NASA covering up a faked Moon landing. The program was aired twice in the United States, in February and again in March of 2001 (it was later broadcast in several other countries as well). Combined, the show had about 15 million viewers in the United States alone. Judging from the discussion groups on the web, the radio and television activity about it, and the vast number of e-mails I received in the following months, something about that program touched a nerve in a lot of people.

That such a huge number of people could seriously believe the Moon landings were faked by a NASA conspiracy raises interesting questions-maybe more about how people think than anything about the Moon landings themselves. But still, the most obvious question is the matter of evidence. What manner of data could possibly convince someone that the Moon still lays untouched by human hands?

The answer is in the photographs taken by the astronauts themselves. If you look carefully at the images, the hoax believers say, you'll see through the big lie.

My question is, whose big lie? The hoax-believers may not be lying, that is, prevaricating consciously and with forethought, but they're certainly wrong. Most don't think they are wrong, of course, and they sure like to talk about it. A web search using the words "Apollo Moon hoax" netted nearly 700 web sites. There are several books and even videos available, adamantly claiming that no man has ever set foot on the Moon.

The most vociferous of the hoax-believers is a man by the name of Bill Kaysing. He has written a book, self-published, called We Never Went to the Moon that details his findings about a purported NASA hoax. Most of his arguments are relatively straightforward. His "evidence" has been picked up by web sites and other conspiracy theorists and usually simply parroted by them.

The evidence worth considering usually comes in the form of pictures taken by the astronauts themselves either on the Moon or in orbit above it. Thousands of pictures were taken by the astronauts, and many of them are quite famous. Some made rather popular posters, and others have been seen countless times as part of news reviews on TV and in newspapers. The overwhelming majority were relegated to an archive where specialists interested in the lunar surface could find them. Most of these consist of picture after picture of the astronauts performing their duties on the surface, and they are unremarkable except for the fact that they show spacesuited human beings standing for the first time in history on the airless plain of an alien world.

Unremarkable, of course, unless you are looking for a dark undercurrent of a NASA conspiracy.

There are five basic concerns raised by the hoax-believers. These are: (1) there are no stars in the astronaut photos, (2) the astronauts could not have survived the radiation during the trip, (3) there is dust under the lunar lander, (4) the incredibly high temperature of the Moon should have killed the astronauts, and (5) the play of light and shadows in the surface indicates that the photos are faked. There are a host of other "problems," a few of which we'll look at after the main points, but let's look at the biggest first.

In the pictures taken by the Apollo astronauts, no stars can be seen. Far from being evidence of a hoax, this is evidence men did go to the Moon. The bright surface and highly reflective spacesuits meant short exposure times were needed to take properly exposed pictures, and the faint stars were too underexposed to be seen.

1. No stars in the astronauts' photos

A typical Apollo photograph shows a gray-white lunar landscape, an astronaut in a blindingly white spacesuit performing some arcane function, a jet-black featureless sky, and sometimes a piece of equipment sitting on the surface, doing whatever it is it was built to do.

The hoax-believers put their biggest stake in these very pictures. Almost without exception, the first and biggest claim of the conspiracy theorists is that those pictures should show thousands of stars, yet none is seen! Kaysing himself has used this argument numerous times in interviews. On the airless surface of the Moon, the conspiracy theorists say, the sky is black, and therefore stars should be plentiful (see chapter 4, "Blue Skies Smiling at Me," for more about this phenomenon). The fact that they are not there, they continue, proves conclusively that NASA faked the images.

Admittedly, this argument is compelling. It sounds convincing, and it appeals to our common sense. When the sky is black at night here on Earth we easily see stars. Why should it not be true on the Moon as well?

Actually, the answer is painfully simple. The stars are too faint to be seen in the images.

During the day, the sky here on Earth is bright and blue because molecules of nitrogen in the air scatter the sunlight everywhere, like pinballs in a celestial pachinko game. By the time that sunlight reaches the ground, it has been bounced every which-way. What that means to us on the ground is that it looks like the light is coming from every direction of the sky and the sky appears bright. At night, after the Sun goes down, the sky is no longer illuminated and appears black. The fainter sky means we can see the stars.

On the Moon, though, there's no air, and even the daytime sky appears black. That's because without air, the incoming sunlight isn't scattered and heads right at you from the Sun. Any random patch of sky is not being illuminated by the Sun, and so it looks black.

Now imagine you are on the Moon, and you want to take a picture of your fellow astronaut. It's daytime, so the Sun is up, even though the sky is black. The other astronaut is in his white spacesuit, cavorting about in that bright sunlight, on that brightly lit moonscape. Here's the critical part: when you choose an exposure time for the camera, you would set the camera for a brightly daylit scene. The exposure time would therefore be very short, lest you overexpose the astronaut and the moonscape. When the picture comes out, the astronaut and the moonscape will be exposed correctly and, of course, the sky will look black. But you won't see any stars in the sky. The stars are there, but in such a short exposure they don't have time to be recorded on the film. To actually see stars in those pictures would require long exposures, which would utterly overexpose everything else in the frame.

Put it another way: if you were to go outside at night here on Earth (where the sky is still black) and take a picture with exactly the same settings that the astronauts used on the Moon, you would still see no stars. They are too faint to get exposed properly.

Some people claim that this still won't work because actually the Earth's air absorbs starlight, making them fainter, so stars should look brighter from the surface of the Moon. That's not correct; it's a myth that air absorbs a lot of starlight. Actually, our atmosphere is amazingly transparent to the light we see with our eyes, and it lets almost all the visible light through. I chatted with two-time Space Shuttle astronaut and professional astronomer Ron Parise about this. I asked him if he sees more stars when he's in space, and he told me that he could barely see them at all. He had to turn off all the lights inside the Shuttle to even glimpse the stars, and even then the red lights from the control panels reflected in the glass, making viewing the stars difficult. Being outside the Earth's atmosphere doesn't make the stars appear any brighter at all.

The accusation made by the hoax-believers about stars in the Apollo photographs at first may sound pretty damning, but in reality it has a very simple explanation. If the believers had asked any professional photographer or, better yet, any of the hundreds of thousands of amateur astronomers in the world, they would have received the explanation easily and simply. They also could easily prove it for themselves with a camera.

I am frankly amazed that conspiracy theorists would put this bit of silliness forward as evidence at all, let alone make it their biggest point. In reality, it's the easiest of their arguments to prove wrong. Yet they still cling to it.

2. Surviving the Radiation of Space

In 1958 the United States launched a satellite named Explorer 1. Among its many discoveries, it found that there was a zone of intense radiation above the Earth, starting at about 600 kilometers (375 miles) above the surface. University of Iowa physicist James Van Allen was the first to correctly interpret this radiation: it was composed of particles from the Sun's solar wind trapped in the Earth's magnetic field. Like a bar magnet attracting iron filings, the Earth's magnetic field captures these energetic protons and electrons from the Sun's wind, keeping them confined to a doughnutshaped series of belts ranging as high as 65,000 kilometers (40,000 miles) above the Earth. These zones of radiation were subsequently named the Van Allen belts.

These belts posed a problem. The radiation in them was pretty fierce and could damage scientific instruments placed in orbit. Worse, the radiation could seriously harm any humans in space as well.

Any electronics placed on board satellites or probes need to be "hardened" against this radiation. The delicate and sophisticated computer parts must be able to withstand this bath of radiation or they are rendered useless almost instantly, fried beyond repair. This is an expensive and difficult process. It surprises most people to learn that the typical computer in space is as much as a decade behind the technology you can buy in a local store. That's because of the lengthy process involved in radiation-hardening equipment. Your home computer may be faster than the one on board the Hubble Space Telescope, but it would last perhaps 15 seconds in space before turning into a heap of useless metal.

Shuttle astronauts stay below the Van Allen belts, and so they do not get a lethal dose of radiation. The doses they do get are elevated compared to staying on the ground, to be sure, but staying below the belts greatly reduces their exposure.

Hoax-believers point to the Van Allen radiation belts as a second line of evidence. No human could possibly go into that bath of lethal radiation and live to tell the tale, they claim. The Moon landings must have been faked.

We've seen once before that basic logic is not exactly the hoaxbelievers' strong suit. It's not surprising they're way off base here, too.

For one, they are vastly confused about the belts. They claim that the belts "protect" the Earth from radiation, trapping it high above us. Outside the belts, they go on, the radiation would kill a human quickly.

That's not true, at least not totally. There are actually two radiation belts, an inner one and an outer one, both shaped like doughnuts. The inner one is smaller, and has more intense-and therefore more dangerous-radiation. The outer one is bigger but has less dangerous properties. Both belts trap particles from the solar wind, so the radiation is worst when an astronaut is actually inside the belts. I talked with Professor Van Allen about this, and he told me that the engineers at NASA were indeed concerned about the radiation in the belts. To minimize the risk, they put the Apollo spacecraft along a trajectory that only nicked the very inside of the inner belt, exposing the astronauts to as little dangerous radiation as possible. They spent more time in the outer belts, but there the radiation level isn't as high. The metal walls of the spacecraft protected the astronauts from the worst of it. Also, contrary to popular belief, you don't need lead shielding to protect yourself from radiation. There are different kinds of radiation; alpha particles, for example, are really just fast-moving helium nuclei that can be stopped by normal window glass.

Once outside the van Allen belts-contrary to the claims of the hoax-believers-radiation levels drop, so the astronauts were able to survive the rest of the way to the Moon. From the belts on out they were in a slightly elevated but perfectly safe radiation environment.

There was risk, though. Under normal circumstances, the solar wind is a gentle stream of particles from the Sun. However, there was a very real danger from solar flares. When the Sun's surface flares, there can be a dramatic increase in the amount of radiation the sun emits. A good-sized flare could indeed kill an astronaut, very nastily and gruesomely. In that sense, the astronauts were truly risking their lives to go to the Moon because solar flares are not predictable. Had there been a good flare, they might have died, farther from home than anyone else in history. Luckily, the Sun's activity was low during the missions and the astronauts were safe.

In the end, over the course of their trip to the Moon and back, the astronauts got, on average, less than 1 rem of radiation, which is about the same amount of radiation a person living at sea level accumulates in three years. Over a very long time that level of exposure might indeed be dangerous, but the round-trip to the Moon was only a few days long. Since there weren't any flares from the Sun, the astronauts' exposure to radiation was actually within reasonable limits.

Conspiracy theorists also argue that the radiation should have fogged the film used on the lunar missions. However, the film was kept in metal canisters, which again protected it from radiation. Ironically, modern digital cameras no longer use film; they use solid-state electronic detectors, which are sensitive to light. Like any other kind of computer hardware, these detectors are also very sensitive to radiation, and would have been next to useless on the Moon, even if they had been encased in metal. In that case, the older technology actually did a better job than would modern technology.

3. Dust on the Moon's Surface

The surface of the Moon is dusty. Before any machines landed on the Moon, no one really knew what the actual surface was like. Scientific analysis showed that the Moon's surface was rocky, and we could even determine the composition of some of the rocks. However, the actual texture of the surface was unknown. It was conjectured by some that the intense sunlight, consisting of ultraviolet light unfiltered by an atmosphere, might break down the rocks into a dust. Micrometeorite hits might do the same. But no one knew for sure if the dust even existed, or how deep it might be.

When the first soft landings were made by Soviet and American probes, it was found that the dust was only a few millimeters to centimeters thick. That was a great relief. No one wanted the Apollo astronauts to sink into a sand trap.

The dust on the Moon is peculiar. It is extraordinarily fine, like well-ground flour. It is also extremely dry, like everything else on the Moon. Unlike the Earth, the Moon has virtually no water at all anywhere on the surface.

Misunderstanding the properties of this dust in an airless environment leads to the breakdown of the next hoax-believer claim, dealing with the landing of the lunar module (or LM), the oddlooking contraption used by the Apollo astronauts to land on the Moon. The LM had four landing legs with disk-shaped feet at the ends, and between them was a powerful rocket used to slow the descent speed as the LM approached the surface.

The conspiracy-theorists claim that the rocket had a thrust of 10,000 pounds, and therefore should have left a substantial crater on the Moon's surface. Also, that much thrust would blow away all the dust underneath it. How could the lander's legs and the astronauts' boots leave imprints in dust? All that dust should be gone!

Both of these claims are wrong. First, the engine was capable of 10,000 pounds of thrust at maximum, but it wasn't simply a roman candle that burns at full thrust when lit. The engine had a throttle, basically a gas pedal, which could change the amount of thrust generated by the engine. When high over the surface of the Moon, the astronaut flying the lander would throttle the engine for maximum thrust, slowing the descent quickly. However, as the lander slowed, less thrust was needed to support it, so the astronaut would throttle back. By the time the lander touched down, the astronauts had cut the thrust to about 30 percent of maximum, just enough to compensate for the lander's own weight on the Moon.

Three thousand pounds of thrust still might sound like a lot, but the engine nozzle of the lander was pretty big. The bell was about 54 inches across, giving it an area of about 2,300 square inches. That 3,000 pounds of thrust was spread out over that area, generating a pressure of only about 1.5 pounds per square inch, which is really pretty gentle, less than the pressure of the astronauts' boots in the dust. That's why there is no blast crater under the lander; the pressure was too low to carve out a hole.

The second claim about dust near the lander is interesting. Why was there dust so close to the center of the landing site that both the lander legs and the astronauts' movements left tracks? This defies common sense, which says the dust should have all been blown away. However, our common sense is based on our experience here on Earth, and it pays to remember that the Moon is not the Earth.

Once again, we have to understand that the Moon has no air. Imagine taking a bag of flour and emptying it on your kitchen floor (kids: ask your parents first). Now stand over the flour, stick your face an inch or two above it, and blow as hard as you can.

When you stop coughing and sneezing from having flour blown into your nose, take a look around. You should see flour spread out for a long way on your floor, blown outward by your breath.

However, you'll see that some flour was carried farther away than your breath alone could have blown it. It's hard to get a good breeze blowing as far away as your outstretched hand because your breath can really only go a few dozen centimeters before petering out. What carries the dust farther than your breath can go is the air that already exists in the room. You blew air from your lungs, and that air displaced the air in the room, and it was that air that carried the flour farther than your breath alone could push it.

However, on the Moon, there is no air. The thrust of the LM engine was substantial, but it only blew the dust out from directly beneath it. Some of that dust blew for hundreds of meters, but, contrary to our experience here on Earth, the dust just outside the immediate area where the exhaust plume touched down was largely left alone. Plenty of dust was left there in which to leave footprints. In reality, a little more dust got blown around than that because the dust blown around directly by the engine can smack into other particles of dust, moving them also. So the "hole" in the dust was bigger than the burn area of the rocket, but not substantially so. Incidentally, in the tapes of the Apollo 11 landing you can hear Buzz Aldrin commenting that they were "picking up some dust" from the engines as they neared the surface. Neil Armstrong, who piloted the LM, complained that the moving dust made it hard for him to figure out how fast they were moving across the surface.

Some hoax-believers also claim that the dust could not keep footprints because it has no water in it, and you need something wet to keep it compacted. This is nonsense. Flour is incredibly dry, yet you can easily leave a footprint in it. This claim is bizarre, and again I am dumbfounded as to why someone would put it forward when it is so trivially easy to prove wrong by experiment. In this case, at least, common sense leads you the right way.

4. The Temperature of the Lunar Surface

Related to the dust problem is that of the Moon's temperature. The Apollo missions were made during the day on the Moon. Measurements of the Moon's surface show that the temperature can get as high as 120°C, hot enough to boil water! Hoax-proponents point out that the astronauts could not have lived through such fierce heat.

In one sense they are correct: that much heat would have killed the astronauts. However, the astronauts were never in that much heat.

The Moon spins on its axis once every 27 days or so. That means that a lunar day is four weeks long, with two weeks of sunlight and two weeks of darkness. Without an atmosphere to distribute the heat from the incoming sunlight, the daylit side of the Moon does get tremendously hot, and the dark side gets very cold, as cold as -120°C.

However, the surface doesn't heat up the instant the sunlight touches it. At sunrise the sunlight hits the Moon at a very low angle, and it does not efficiently heat it. It takes days for the lunar surface to get to its high temperature, much as the worst heat of the day on Earth is reached after the Sun reaches its peak. NASA engineers, knowing this, planned the missions to take place at local morning, so that the Sun was low in the sky where they landed. You can see this in every photograph taken from the surface; the shadows are long, indicating the Sun was low in the sky.

As it happens, the spacesuits were designed to keep the astronauts cool, but not because of the outside heat. In a vacuum, it's very difficult to get rid of the astronauts' own body heat. An astronaut inside an insulated suit generates a lot of heat, and that heat needs to get dumped somehow. The suits needed ingenious methods to cool the astronauts. One way was to pipe cool water through tubes sewn into their undergarments. The water would warm up, picking up their waste heat, then flow into the backpacks where the heat could be dumped away into space.

So there really was a problem with temperature, but it was internal, not external. Another hoax claim, frozen in its tracks.

Incidentally, the dust on the surface of the Moon is a terrible conductor of heat. Powdery materials usually are. Although the dust was actually warmed by sunlight, it wasn't able to transfer that heat well to the astronauts through their boots. Oddly, even though the surface of the Moon gets to 120°C at noon, the dust is only that hot for a short distance down, because the heat can't flow well below that depth. Below that depth, the rock is eternally freezing cold, insulated by the dust and rock above it. The dust cools rapidly once the Sun sets. During a lunar eclipse, when the Moon is in the Earth's shadow, the lunar temperature has been measured to drop very quickly. The dust gets as cold as the rock beneath it.

That coldness came back to haunt one astronaut. During an excursion, Apollo 16 astronaut John Young realized that the rocks they had collected were all rather small. He wanted one really big one to impress the scientists back home. He grabbed a rock weighing roughly a kilogram (two pounds), and placed it underneath the lander, in shadow, while he closed up shop to prepare for the return to Earth. When he was done, he put the rock on the LM and repressurized the module.

It was then that Young realized he needed to rearrange the rocks a bit to balance them in the LM, making sure that the spacecraft wouldn't tilt dangerously during takeoff due to an imbalance in the mass distribution that the automatic controls couldn't handle. He had already taken his gloves off, and when he grabbed the big rock, he got a surprise: the rock had been in the shadow long enough to dump its extra heat, and had become bitterly cold! Young was actually lucky not to get frostbite. When Young retold this story to Paul Lowman, a NASA geologist and lunar expert, Lowman exclaimed, "This is the only time I've ever heard somebody describe the actual temperature of the Moon as he actually felt it!"

Hoax-proponents also claim that the film carried by the astronauts would have melted in the tremendous lunar heat. In reality, the opposite problem is true: they didn't have to worry about film melting; they had to insulate it to keep it from freezing.

5. Tricks of Light and Shadow

Another common line of "proof" of a NASA conspiracy has to do with the play of light and shadows on the Moon. The most common of these claims concerns the blackness of the shadows. If the Sun is the only source of light, say the hoax-believers, then shadows should be absolutely black because there is no scattered sunlight from the air to fill them in. Without any light illuminating the ground in the shadow, it should be completely, utterly black.

On the Earth, we are accustomed to shadows that are not actually totally black. This is due primarily to our bright sky. The Sun itself casts a sharp shadow, but the light from the air in the sky illuminates the ground in our shadow, making us able to see objects there.

On the Moon, where the sky is black, conspiracy theorists claim the lunar surface inside the shadow should be completely black. If the Sun is the only source of light, they say, the shadows should be black as pitch. Yet, in the astronaut photographs we commonly see shadows filled in a bit, as if there were another source of light. Obviously, to the hoax-proponents, since the Apollo photographs were taken on a soundstage on Earth, the source of this light is the air inside the building, scattering the light from a spotlight.

However (stop me if you've heard this before), they're wrong. There is a source of light on the Moon besides the Sun, and we've already said what it is: the Moon. The sky may be black, but the surface of the Moon is very bright and reflects the sunlight, filling in the shadows. This is another trivially simple answer to one of the hoax-proponents' "puzzling" questions.

Interestingly, sometimes the shadows falling on the lunar surface appear to be filled in as well. Ironically, the source of light is most likely the astronauts themselves. The spacesuits and the LM are brightly lit by the Sun and the lunar surface, and that light is reflected back onto the lunar surface, filling in the shadows a bit. This exact same technique is used by photographers and cameramen, who employ umbrella-like reflectors to fill in the shadows when photographing a scene.

However, if you look more closely at the photographs, the problem does get more complicated. In what has become the most famous picture taken on the Moon, Neil Armstrong snapped an image of Buzz Aldrin standing near the LM during the Apollo 11 mission (see page 169). We see Buzz facing the camera, lit by the Sun from behind and to the right. Reflected in his helmet we can see Neil's image as well as the lander leg and various shadows.

One of the most famous photographs from the Apollo missions, the "Man on the Moon" picture of Buzz Aldrin. Conspiracy theorists point to many clues that indicate the image was faked: the lack of stars, the filled-in shadows, and the apparent spotlight effect. However, all of this is in fact evidence that the picture is genuine. Note also Aldrin's knees; they are covered with ash-gray lunar surface powder from the many times Buzz had to dip down to pick up a dropped tool or collect a rock sample. Despite what others might say, this image was indeed taken on the surface of an alien body, the Earth's Moon. (Photograph courtesy of NASA.)

This image is of paramount importance to the hoax-believers. It embodies two claims critical to their arguments: From the way the ground is illuminated Aldrin is clearly being lit by a spotlight aimed directly at him, and from shadows in his visor it looks as if that spotlight is nearby.

This picture is oddly lighted, but not because of any human trickery. Actually, the spot of light results from a peculiar property of the lunar surface: it tends to reflect light back in the direction from which it comes. This is called backscatter, and it is very strong on the Moon. If you were to shine a flashlight in front of you there, you'd see the light strongly reflected back to you. However, someone standing off to the side would see hardly any reflected light at all.

Actually, you've almost certainly seen this effect on your own. You might guess that the half-full Moon is half as bright as the full Moon, but that's not correct. The full Moon is roughly ten times as bright (H. N. Russell, "On the albedo of planets and their satellites," Astrophysical journal 43 [1916]: 103). That's because at full Moon, the Sun is shining from directly behind you, straight onto the Moon. The lunar soil then obligingly sends that reflected light straight back to you. At half Moon, the light is coming from the side and much less is reflected in your direction, making the Moon look fainter.

That's why Aldrin appears to be in a spotlight. In the area where he's standing, the light is reflected straight toward Armstrong's camera. Farther away from Aldrin, though, the light gets reflected away from the camera, making it look darker. The effect generates a halo of light around Aldrin.

The technical name for this glow is heiligenschein, which is German for "halo." You can see it yourself on a dewy morning. Face away from the Sun so that the shadow of your head falls on some wet grass. You can see the glow of backscattered sunlight surrounding your shadow's head, looking very much like a halo. You can also do this where the ground is dusty, such as in a baseball diamond infield. The effect can be very striking. This "spotlight" effect can be seen in many Apollo photographs, but only when the astronaut taking the picture had his back to the Sun, just as you'd expect. There's no spotlight, just some odd-but naturalphysics at work.

Incidentally, the opposite effect happens when you drive a car on a rainy night. Wet pavement reflects the light forward, away from you. Oncoming cars can see your headlights reflected in the pavement, while your headlights hardly seem to light up the road in front of you. The light is thrown ahead of you, not back at you, making it hard to see the road.

The second claim about the photograph deals with the shadows. If you look in Aldrin's visor, you'll see that the shadows aren't parallel. If the Sun is the source of light, all the shadows should be parallel. Instead, they point in different directions, which means the source of light must be close by. Ergo: it's a spotlight.

Well, we've already seen it's not a spotlight, so we know it must be the Sun. Actually, this claim is another ridiculously easy one to refute. We see the shadows reflected in a curved visor. The curvature of the visor distorts objects in it, like a fisheye lens or a funhouse mirror. The shadows are curved because the visor is curved. That's all there is to it. Again, no fakery, just simple optics that everyone has seen at some point in his or her life.

However, there are also some images that are not visor reflections, but still seem to have shadows pointing in different directions. Again, if the Sun is the only source of light, shadows should be linear and parallel. Clearly, sometimes they are not parallel. To the conspiracy theorists, of course, this is more evidence that the images are fake.

Have you ever stood on a set of railroad tracks and seen how they appear to converge far away, near the horizon? This is an effect of perspective, of course. The railroad tracks are parallel (they wouldn't be much use if they weren't), but our eyes and brain interpret them as converging.

The shadows cast by the astronauts, rocks, and other surface features appear to be nonparallel, but this is just an effect of perspective, similar to the apparent converging of railroad tracks on the horizon.

The same thing is happening in the lunar photographs. The shadows don't appear to be parallel because of perspective. When comparing the directions of shadows from two objects at very different distances, perspective effects can be quite large. I have seen this myself, by standing near a tall street lamp around sunset and comparing its shadow to that of one across the street. The two shadows appear to point in two very different directions. It's actually a pretty weird thing to see.

Again, this is something that can be investigated quite literally in your front yard, and is hardly evidence of a multibillion-dollar conspiracy.

There's an interesting lesson here about the claims of the hoaxbelievers.

In many cases they use simple physics and common sense to make their points. Usually their initial points make sense. However, they tend to misunderstand physics, and common sense may not apply on the airless surface of an alien world. Upon closer inspection, their arguments invariably fall apart.

I could go on and on with more examples. Debunking the hoax-believers' claims could fill a book. That's not surprising, considering several books have been written by them. I have no doubt the books sell well. Conspiracy books always do. I also have no doubt that a book dedicated to debunking them would not sell well. A whole book pointing out the believers' errors would be tedious, and it isn't necessary. The examples above are the strongest they can muster, and they fall apart easily when shaken. Their other arguments are even weaker.

But the interesting part is the seeming simplicity of their claims. Not seeing stars in the Apollo pictures is so obvious, so basic a mistake. The other arguments they make seem obvious as well.

But let's a have small sanity check here. Let's say NASA knew it couldn't put men on the Moon, and knew it would lose all its money if it didn't. They decided to fake the whole lunar project. They built elaborate sets, hired hundreds of technicians, cameramen, scientists knowledgeable enough to fake all this, and eventually spent millions or billions of dollars on the hoax. Eventually, they put together the greatest hoax in all of history, yet they forgot to put stars in the pictures?

There's more. It has come to light in recent years that the Soviets were well on their way to sending men to the Moon in the 1960s as well. Their missions never got off the ground, but the Soviets worked very hard on them, and of course they were watching carefully when NASA broadcast its own footage. Both superpowers had spent billions of dollars on their respective lunar projects; national prestige was at stake for the two countries that just a few years before were on the verge of nuclear war. You can imagine that if the Soviets had faked their missions and forgotten such obvious flaws as stars in images and shadows that went in the wrong direction, the American press would have savaged them beyond belief. Do the conspiracy theorists honestly think that Tass or Pravda would have done any differently to the American project? It would have been the Soviets' greatest victory of all time to prove that the Americans had botched their biggest peacetime project in history, yet even they acknowledged the truth of the Moon missions.

In the end, truth and logic prevail. America did send men to the Moon, and it was triumph of human engineering, perseverance, and spirit.

A postscript: after Kaysing finished his book We Never Went to the Moon, he approached Jim Lovell with it. Lovell was the commander of Apollo 13, and literally came close to death trying to save his crew and his ship after an explosion crippled the spacecraft. Lovell's stake in the space program is almost beyond comprehension.

So you can imagine Lovell's reaction when he read Kaysing's book. In the San Jose Metro Weekly magazine (July 25-31, 1996), he is quoted as saying, "The guy [Kaysing] is wacky. His position makes me feel angry. We spent a lot of time getting ready to go to the moon. We spent a lot of money, we took great risks, and it's something everybody in this country should be proud of."

Kaysing's reaction to Lovell's comments? He sued Lovell for libel. In 1997, a judge wisely threw the case out of court. There's still hope.