Why does the sky look black from space?
Because the camera is set to photograph a bright object like the Earth or
Moon, and so it has to use a short exposure and slow f/stop. This is exactly
the opposite of what you need to see stars in the sky, so the sky looks black.
The above photo was taken by the Galileo Mission of the asteroid Gaspra. Note the black sky surrounding the asteroid. The cameras were optimized to photograoh Jupiter which is very bright, so faint stars against a black background were not part of the optimization parameters. Go into an illuminated parking lot and look at the sky on a clear night. You
will see the same effect as your eye is flooded by bright lights and 'stops
down'.
Copyright 1997 Dr. Sten Odenwald
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