Dark Sky, Bright Sun

In low Earth orbit there is not enough atmosphere to diffuse
and scatter sunlight, so shadows are black and the sky is dark -
even when the Sun shines. The harsh lighting produced this dramatic
effect as mission specialist Gregory Harbaugh photographed colleague
Joseph Tanner during their second spacewalk to service the Hubble Space
Telescope in February 1997. The aft section of the Space Shuttle Discovery
is visible in the background with the Sun hanging over a delicate crescent
of the Earth's limb. A checklist is attached to Tanner's left arm, and
Harbaugh's reflection is just visible in Tanner's visor.