Earth Shadow
Earth does cast a shadow through space; and it starts in the atmosphere. It can be seen every clear day just after sunset, and just before sunrise, creating a sandwich effect. The pinks are outside the shadow -- hues of the setting sun refracted through the western sky before being reflected off upper-atmospheric particles in the east. Since the shadow below has no direct sunlight, it is missing the sunset's pinks, and only carries blue shades typically scattered by atmospheric gases. Our view of the Earth's shadow shows up sharpest, and the refracted pink of the upper atmosphere brightest, when the lowest few thousand feet of air above surface (the "boundary layer") are relatively clean of pollution, haze and dust. Such was the case here on the northwest corner of Lake Huron, behind a cold front, in relatively clean air blown from northwest Ontario and Lake Superior.
Mackinaw City MI (2 Aug 99), looking ESE.
(GPS)
