Because of the great distance and the resolution of the human eye, I
don't think any built structures are visible from the moon. These days,
the Great Walls of China (after all, there were a number of them) blend
into the surrounding scenery so well that you can't even spot them using
Google earth. What you can see from space (but usually no higher than
about 350 miles or so) are strip-mined areas, such as we have here in
Kentucky, and large swatches of deforestation, especially in the Amazon
River basin. At present, the most visible mark of humans to someone in
orbit (provided we discount the illuminations of cities at night) would
be a certain predilection for very large scale destruction. It's easier
to tell what we've destroyed (or economically altered, depending on your
point of view), as opposed to what we've built. I can only assume that
large-scale deforestations from the late 1800s and early 1900s would
also have been visible from space. That might be an interesting
historical archaeology topic - "Historic Instances of Large Scale
Disturbances Visible From Space, ca. 1800-1900". 

Daniel B. Davis
Archaeologist Coordinator
Kentucky Transportation Cabinet
Division of Environmental Analysis
200 Mero Street
Frankfort, KY 40622
(502) 564-7250


-----Original Message-----
From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of Bob
Hoover
Sent: Monday, February 12, 2007 11:29 AM
To: [log in to unmask]
Subject: Re: China to measure the Great Wall

The Antonine Wall was a brief and very simplified version of Hadrians
Wall. 
You can now walk a trail the entire length of the latter.   Like the
Chinese 
wall, both were designed to mark a boundary, not to keep people in like
the 
Berlin Wall.   I read somewhere that the Wall of China is the only human
feature 
svisible from the moon.   Maybe the lights of LA can now complete with
it.   
When they merasure it, will they use metric? Chinese li? Certainly not
the English system! The westward extension of the wall is particularly
interesting. 
Aurel Stein in Ca. 1910 found a series of forts and signal stations
along the northern fringe of the Tarim Basin, similar to signal stations
in Roman Britain and the Rhine-Danube frontiers. Perhaps some Roman
military engineers liberated 
from the Partians by the Han armies lent their expertise?   If so, this
will 
almost certainlhy result in a scientific cover-up similar to that of the
red haired Tocharian mummies of the same area. These connections are
always fascinating but speculative.

Bob Hoover