The Earth's Terminator The Dark side of the earth roughly starts
at the terminator, or the border between darkness and light.
Picture taken July 21, 2001(black levels enhanced as with
following picture): Note in particular 2 locations given by
coincidence of time: Halifax Canada and Panama city. Both
locations are in the dark zones of the Earth. However Halifax is
really at the limit between light and darkness, the sun there is
0.7 degrees below the horizon. On the other hand, Panama has the
sun 2.3 degrees below and is really in the dark zone. Contrast
this with a winter picture of the North Pole taken March 16,
2001: In this case, there is light beyond the pole, even with
the sun being 1.5 degrees below the horizon. In fact light is
seen for one or two more degrees of latitude beyond the pole
More such comparisons are needed. The Terminator border in the
Polar regions are largely displaced due to strong refraction
well beyond horizon refraction found at the equator, because of
extremely cold and dense air a