Answer Man: Can you see the Great Wall of China from space?

January 7, 2014 

Q. Please settle a disagreement: I have always been told that the Great Wall of China is the only man-made Earth object that is visible from space. Now a friend tells me it's not true. Have I been spreading misinformation?

-- S.D., of New Baden

A. Believe it or not, Robert Ripley was wrong at least once. And, for the most part, so are people who continue to spread this urban legend that has been circulating in one form or another for nearly a century.

In 1932, Ripley in one of his widely read "Believe It or Not!" cartoons boldly claimed that this historic wall, parts of which date back 2,800 years, is "the mightiest work of man, the only one that would be visible to the human eye from the moon."

Alas, once we reached the moon, we found we certainly could not see the Great Wall.

"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," said Alan Bean after his Apollo 12 mission. "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 from that point, either."

Still, people didn't give want to give up on this boast. Instead of "the moon," the claim over the years apparently was whittled down into "from orbit." Unfortunately, even this more limited piece of puffery will get you into trouble.

For one thing, it is not the only man-made object visible from, say, a low orbit of 160 to 350 miles up, roughly the path of the old space shuttles. If you search NASA's Earth from Space photographic archive, you'll find photos with highways, bridges, dams - even parts of the Kennedy Space Center.

More important, these other structures are far more discernible than the Great Wall, which apparently is nearly impossible to spot.

"We look for the Great Wall of China," shuttle astronaut Jay Apt said once. "Although we can see things as small as airport runways, the Great Wall seems to be made largely of materials that have the same color as the surrounding soil. Despite persistent stories that it can be seen from the moon, the Great Wall is almost invisible from only 180 miles up."

But the knockout blow came in 2003 when Yang Liwei, the first Chinese man in space, returned from his 14-orbit mission aboard Zhenshou 5 and said that even he could not see the Great Wall. The admission so rocked the country that the Ministry of Education reportedly seriously began considering revising its school textbooks, which, of course, had long carried the claim as a source of national pride.

Fortunately for the Chinese, it didn't come to that. Some astronauts, including Eugene Cernan and Ed Lu, say that under certain lighting conditions, the wall can be seen, especially when the sun is low and casts long shadows. Others say they can see portions when snow lies on both sides of the wall but not on the wall itself, providing a color contrast.

And American astronaut Leroy Chiao may have saved the day in 2004 and 2005 when two pictures he snapped from the International Space Station seemed to show sections of the wall, although Chiao himself said he wasn't sure. Still, the jubilant Chinese ran one prominently in its national papers.

In the end, however, the Chinese may have only themselves to blame for their frequent disappointment.

"The biggest problem nowadays is the pall of pollution which exists over much of China," astronaut Jeffrey Hoffman said once. "It effectively makes it impossible to see almost anything."

If you'd like to try and make it out, go to NASA's webpage at www.nasa.gov/vision/space/workinginspace/great_wall.html.

Q. As retirees with more time on our hands, we put up some bird feeders and found we enjoy watching the varieties we've attracted. During this winter storm, we've had upwards of 25 on our deck scrambling for seed. Our problem is that, being new to bird watching, we'd like a reference book to help us identify our buffet guests.

-- David Taylor

A. My friend Mardi Mauch at Wild Birds Unlimited in Swansea highly recommends feathering your literary nest with Stan Tekiela's "Birds of Illinois Field Guide."

On amazon.com, it gets an almost unanimous five-of-five rating from readers. Typical:

"This is a great book, especially if you are new to birding like I am. It contains 111 species that you'll find in Illinois and also has a 'compare' section if you aren't sure which finch you're seeing. Very friendly. The first page is a bird color guide. If you are trying to find a bird that is mostly gray, you flip to the gray section. A lot of information is provided on each bird. I especially liked 'Stan's Notes,' which provides naturalist information and curious little facts that will leave you saying, 'Hmmm, I didn't know that!'"

It's $12.95 at the Swansea store.

Today's trivia

Where in ancient Rome would you have found a frigidarium?

Answer to Tuesday's trivia: When Harry Truman defeated Thomas Dewey in the 1948 presidential election, Bob Hope, ever the comedian, sent him a one-word congratulatory telegram. It offered this terse advice: "Unpack." It tickled Truman so much that he kept it under the glass on the top of his desk in the Oval Office.

Send your questions to Roger Schlueter, Belleville News-Democrat, 120 S. Illinois St., P.O. Box 427, Belleville, IL 62222-0427 or rschlueter@bnd.com or call 618-239-2465.

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