Was it earthshine?

[entropia]

I was driving towards the west after sunset and I realized the moon was in front of me. It was a very thin crescent  but it looked shinier towards the center of the crescent. I was thinking that it was the youngest moon I have seen, it looked almost like a line. Was that gleam earthshine?  Does the earthshine show on a full moon? Did anybody see the moon yesterday?

[Bizibilder]

If you are viewing a thin crescent Moon and you can see the whole of the Moons disc, very dimly illuminated apart from the bright sunlit crescent, then you are seeing Earthshine.  It is the Sun's light being reflected from the Earth onto the Moon and back again to the Earth.

Here is a Pic I took a while ago to show the effect - the Bright crescent has had to be overexposed to see the earthshine effect:

[entropia]

That is a nice picture of yours. Yes, I could see the disc very dimly, that's how I realized it was the moon. It looked like a line perched on the sky, It is a very nice sight, I wonder how many drivers on the highway enjoyed it as well

[AndyWB]

Yeah, Earthshine was very visible tonight over in the UK. I can't see why that wouldn't be so over there too.

[bingevader]

There's a Waterboys song that describes it quite nicely! 

Lovely picture Roger.

Cheers

[acey]

I had no view of the moon yesterday, but tonight (Sunday) the Earthshine was very clearly visible. As has been said, it's caused by sunlight reflected from Earth (hence the name), and if you think about the geometry you'll realise that you can only ever see it when the Moon is a fairly thin crescent, i.e. shortly either side of New Moon.

Think of Moon, Earth and Sun in a line (Earth in the middle). That's Full Moon, when we see the Moon fully illuminated. If you were standing on the Moon there would be a "New Earth" (or an eclipse if things were exactly in a line along the plane of the orbits, which doesn't happen very often).

Now make it Earth, Moon, Sun in a line. This is when we have New Moon, and if you were standing on the Moon you would have Full Earth, which would look a lot bigger and brighter than Full Moon does to us. When we look at Earthshine we are seeing the Moon's surface illuminated by a (nearly) Full Earth. Someone standing on the thin crescent part of the Moon would see the Sun (low on their horizon) as well as the Earth, while someone on the darker part sees only the Earth.

As the month goes on, the Earth looks more and more crescent-like from the lunar surface, while the Moon looks bigger and bigger to us. So the Earth gets less and less bright in the lunar sky, while more and more of the Moon becomes brightly illuminated from our viewpoint, So the Earthshine gets very much dimmer, to the extent that we just don't see it.

The Moon with Earthshine will look the same from anywhere on Earth, assuming equivalent atmospheric conditions.