The Gegenschein Over Chile
Explanation:
Is the night sky darkest in the direction
opposite the Sun?
No. In fact, a rarely discernable faint glow known as
the gegenschein (German for "counter glow") can be seen 180
degrees around from the Sun in an extremely dark
sky.
The gegenschein is sunlight back-scattered off small interplanetary
dust particles.
These dust particles are millimeter sized splinters from
asteroids and orbit in the
ecliptic plane of the planets.
Pictured above from last year is one of the more spectacular pictures of
the gegenschein yet taken.
Here a deep exposure of an extremely dark sky over
Las Campanas Observatory in
Chile shows
the gegenschein so clearly that even a surrounding glow is visible.
Notable background
objects include the
Andromeda galaxy,
the
Pleiades star cluster,
the
California Nebula,
the
belt of Orion just below the
Orion Nebula and inside
Barnard's Loop, and
bright stars
Sirius and
Betelgeuse.
The gegenschein
is distinguished from
zodiacal light near the Sun by
the
high angle of reflection.
During the day, a phenomenon similar to
the gegenschein called
the glory can
be seen in reflecting air or clouds opposite the Sun from an airplane.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
