Posted by GPP on November 07, 2003
In Reply to: The view from above posted by doc on November 06, 2003
: : : : : : : Hi folks! I got into a discussion with a colleague of mine on whether the Great Wall of China was visible from the moon or not.
: : : : : : : can someone please confirm if I am right or not
: : : : : : : Ans while we are at it Shakespear said "To be or not to be"
: : : : : : : "be" what???? and is this phrase from "As you like it"?
: : : : : : a) It's *not* visible to the naked eye from the surface of the moon - not by a long chalk.
: : : : : : b) "To be" in this case means "to exist". That is, whether to live or not.
: : : : : : c) It's from Hamlet, not As You Like It.
: : : : : Astronauts *can* see the Great Wall with the naked eye when they are orbiting the earth. I have occasionally heard it said that the wall is the only human achievement visitble from space. Perhaps that's where your friend got the idea it was visible from the moon.
: : : : Here's a fun site -- http://terraserver-usa.com/ I was able to find an aerial view of my current home and my old homeplace on White Oak Mountain.
: : : Hmmm. That address isn't working. Trying new one.
: : : http://www.terraserver.com/
: : According to astronauts, the Great Wall is not visible to the unaided eye at heights greater than 180 miles above the surface.
: : http://www.vibrationdata.com/space/greatwall.htm
: There is a math/trig way to figure out how far away anything is theoritically visable. It is not too difficult to understand if you have a bit of serious math. From the moon? No! But there is some significant distance, like perhaps the 180 miles mentioned above, where the wall is visable if the weather permits.
You don't even need the math.
"Quick definitions (Great Wall of China)
noun: a fortification 1,500 miles long built across northern China in the 3rd century BC; is 1,500 miles long and averages 6 meters in width"
Now put something very very long, but only six meters wide, on the moon, and look at it from your back yard. Can you see it?