Alex Kilpatrick:
I thought of this after the previous question about whether a telescope
could see any of the apollo stuff on the moon.
If you were standing on the moon with an average telescope (say 8"),
could you see any man-made landmarks on Earth?

If you look he
http://www.snopes.com/science/greatwal.htm
Alan Bean is quoted as saying that no man-made object is visible from
the moon, but he didn't use a telescope.

Think about it. I've seen the so-called Great Wall, and it's maybe 5-6
meters wide in those areas that have been restored for the sake of
tourism, while most of it consists of piles of rubble that are barely
distinguishable from the rest of the rocky landscape that it traverses.
From an airliner one can discern that the rubble follows a circuitous
path to someplace. Can an 8" telescope on earth resolve a
six-meter-wide feature on the moon? No, and an 8" telescope on the moon
could not resolve a six-meter-wide feature on the Earth, either.

It seems to me that such a telescope might see the lights of a large
city at night if the weather in that city's locale were sufficiently
clear. Think of the stupid zillion-watt light at that casino in Vegas,
e.g. It might also be possible to see the larger man-made lakes, such
as Lake Kariba in Zimbabwe or Lake Nasser behind the Aswan High Dam,
providing that the angle of the sun was such that they were reflecting
considerable light.

Consider a military reconaissance satellite, though. Imagine an
enlarged Hubble pointed downward!

Davoud

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