All text from Wikipedia.
Earthshine is reflected Earthlight visible on the Moon's night side. It is also known as the Moon's ashen glow or as the old Moon in the new Moon's arms.
Earthshine is most readily observable shortly before and after a New Moon, during the waxing or waning crescent phase. When the Moon is new as viewed from Earth, the Earth is nearly fully lit up as viewed from the Moon. Sunlight is reflected from the Earth to the night side of the Moon. The night side appears to glow faintly and the entire orb of the Moon is dimly visible.
Below is a higher contrast version of the image above.
Processed using Registax and wavelets.
Negative enhanced image to show ray patterns