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Credit & Copyright: John Chumack
Explanation:
The Horsehead
Nebula is one of the most famous nebulae on the
sky.
It is visible as the dark indentation to the red
emission nebula
in the center of the above photograph.
The horse-head
feature is dark because it is really an opaque
dust cloud that lies in
front of the bright red
emission nebula.
Like clouds in
Earth's atmosphere, this cosmic cloud has
assumed a
recognizable shape by chance.
After many thousands of years, the internal motions of the cloud
will alter its appearance.
The emission nebula's red color is caused by
electrons recombining with
protons to form
hydrogen atoms.
Also visible at the bottom left of the picture is a greenish
reflection nebulae that
preferentially reflects
the blue light from
nearby stars.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Horsehead Nebula
Publications with words: Horsehead Nebula
See also: