Science is a wonderful thing ... and for comic value "pseudo-science" is even better. What precisely is pseudo-science?  It's that collection of fables that sounds as though it ought to be true, might be true, or contains some parts that are true, but in reality lacks substance in the form presented.

Among the best examples of pseudo-science I know are the many stories surrounding the "Great Wall of China." This edifice, undeniably a substantial achievement, is said, for instance to be the only man-made structure visible from the moon.  Recently, equally ludicrous claims have been made for the Yangtze River Dam in China.  Odd, isn't it, that China appears to be the sole nation capable of spawning artifacts that popular imagination believes should be viewable from some orb other than our own.

Hum ... impressive though it may be, why, of all the works of civil engineering, should a wall that doesn't even cast that tall a shadow (albeit a long one) be the only hand-built structure visible from the moon? What's more, why do people believe it adds to the Wall's grandeur to claim it can thus be seen?

I had a long distance argument with the editor of an article on the Wall that appeared in an Oxford University Press reference book.  Despite any evidence I brought forth, and all discussions of eyewitness accounts, she steadfastly maintained,

"I still believe you can see it."

In my fervor to debunk baseless fables I once took the opportunity to ask Frank Borman (when I was introduced to him as the Chairman of Eastern Airlines) whether it was true. Frank, as you will recall, is among the very few people who can authoritatively say what can and can't be seen from the moon ... having orbited there in late 1968.

He emphatically informed me that the only thing one sees on earth from the moon is lots of blue and white, with occasional slight patches of brown and green.

But, You Reply, "I Won't Believe It Unless I See It in Print."

According to "More Misinformation," by Tom Burnam and published in 1980, further weight to this argument can be found in a letter from astronaut Alan Bean on the subject:

"The only thing you can see from the moon is a beautiful sphere, mostly white (clouds), some blue (ocean), patches of yellow (deserts), and every once in a while some green vegetation. No man-made object is visible on this scale. In fact, when first leaving earth's orbit and only a few thousand miles away, no man-made object is visible at that point either."

Don't Believe Alan Bean?

You don't have to take my word for it after all ... you can take the word of people who have actually been there and can speak as eyewitnesses.  If you choose not to accept their statements, perhaps you're on the wrong side of this issue.  This subject has been discussed thoroughly in popular scientific writings. 

A person with perfect eyesight is able to resolve up to about one minute of arc without binoculars or a telescope, as is well known, proven, and clearly established in a variety of reference texts. The Wall is, very approximately, 6 meters wide. This means that it is not directly visible above an altitude of about 20 kilometers, or just over twice the height of Mount Everest. Even if its shadow is taken into account, this would only make it visible, in places, up to perhaps about 60 kilometers at the most. Because of atmospheric drag, this is still below the height necessary for a stable spacecraft orbit.  Being visible from the moon is out of the question.

The Long and the Short

Still not convinced?  Think that I'm stupid, misinformed, of otherwise deluded because I dare question one of pseudo science's most cherished tenants?  Here are a few other sources you can turn to:

Again, you don't have to take my word for it ... a bit of reference checking will do the trick ... China experts notwithstanding.