In article , Davoud wrote:
LarryG:
When observing Earth's night side, it should be possible to see lights
from cities and major highways.

Cities, maybe. Highways, almost certainly not.

On the daytime side, it may be possible
to see airport runways, if sufficient contrast with surroundings,

Too small, and in urban settings, insufficient contrast.

sunlight
reflecting off glass or swimming pools,

Unlikely, unless your pool is a few hundred miles wider than mine.

Davoud're probably right about the others, but calm swimming pools
in the area where they'd give a specular reflection of the sun
should be *easily* visible with a small telescope. A 5-meter 100%-reflecting
mirror, seen from 240000 km, would reflect about 6e-12 of the Sun's surface;
since the Sun's magnitude is about -26, that would give the mirror's
reflection about mag +2. I'm not sure what fraction of light would be
reflected; at normal incidence, it should be about ((1.33-1)/(1.33+1))^2,
or about 2%, or about another 4 magnitudes. At shallower angles
they'd be brighter.

So one lousy, calm (waves mostly less than .25 degree) Earthbound
swimming pool catching the sunlight should be at least mag 6
as seen from the moon!

How big would the patch of Earth be, where swimming pools would have
a chance of doing this?

The Sun's disk is .5 degree across, so swimming pools whose normal
directions lie in a .5 degree range will reflect sunlight to our observer.
That's about 30 miles on Earth's surface, or about a 40-arc-second patch
as seen from the moon.

Some bright patches would be outside this area: those with small
ripples on them, so that they'd send some sunlight our way.

It should be quite a sight -- rather like a superbright open cluster!

Stuart