Expert: Courtney Seligman - 6/28/2010

Question
what type of lights or man made structures or for that matter any type of structures can be seen from space?

James

Answer
I presume you mean without optical aid...

From low or near Earth orbit, city lights can be easily seen on the night side of the Earth, just as they would be from an airliner -- just not in as much detail. Similarly, many larger cities could be distinguished from emptier areas, and a few (large) individual structures.

However, (according to the lunar astronauts) from the Moon, there was no sign of human existence, at all. Even the lights on the night side were too faint to see, and all cities and structures were too small to notice. Of course, the astronauts were only there during the lunar day, and there was some tinting on their sun visors and spacecraft windshields, so perhaps some of the night-side lights might have been visible, under better circumstances. So basically, it would seem that very close to the Earth, all sorts of things could be observed, but by the time you get as far away as the Moon, almost nothing could be seen, save for the Earth's natural features (continents, oceans and clouds).

At greater distances, things would be even more difficult. So even a Martian equivalent of the Hubble Space Telescope wouldn't be able to see that there was anything occurring on the Earth of any non-natural nature.