[ExI] Fermi question

[Ben Zaiboc]

Kelly Anderson <kellycoinguy at gmail.com> asked:

>On Thu, Dec 22, 2011 at 5:49 AM, Ben Zaiboc <bbenzai at yahoo.com> wrote:
>>
>> The idea of the Great Wall of China being visible from space pre-dates space travel. ?It was /expected/ to be visible from space, but in fact isn't.
>>
>> It's too similar to its surroundings to stand out, which is why far smaller structures are visible from orbit, but the wall isn't. ?Apparently, from the Moon, absolutely nothing man-made is visible on the earth.
>>
>
>Can't you see the big lighted cities at night from the moon??? Seems
>like seeing LA all lighted up wouldn't be that hard. Of course that
>isn't really a "structure"...


Well, I was just reporting what people who've actually been there have said.  I don't know if any of the moon landings took place when the night-side of earth was visible, so maybe they just didn't have a chance to see.  Interesting quesion though.  Even the biggest urban sprawls would be a tiny pin-prick from quarter of a million miles away, and street lights are pretty dim, so maybe not.

Ben Zaiboc