First frame of QT movie

Sunlight illuminates the daytime half of the earth. Most of that sunlight is absorbed by the earth and drives its climate system, but some of it is reflected back into space, and in particular, some of the reflected light reaches the moon. If you were standing on the moon watching the earth, you would see it going through phases opposite to those of the moon: when the moon was new, the earth would be full (and you could see half of the globe at once), while when the moon was full, the earth would appear as a thin crescent.

It's been a long time since anyone's been on the moon to watch the earthshine, but we can use the moon as an imperfect mirror, and see the earthshine reflected back to us on earth as the faint glow of the dark part of the lunar disk. The earthshine will be bright and easy to observe near new moon, while it will be dim near the full moon.

The following link is a QuickTime movie showing how earthshine is produced. This file is in QuickTime format and about 10 MB in size.
Download the compressed movie.

There is also an uncompressed version of the QuickTime movie. This is a very large file (330 MB) so even with a high-speed connection it will take some time to download. This version has no audio.
Download the uncompressed movie.

The compressed movie without audio is also available.
Download the compressed movie without audio.

The audio from the movie is available in MP3 and QuickTime IMA4:1 formats.

If you need a QuickTime player for your computer, you can download one from here.

Image credit: Earthshine Project, Caltech.