Explanation:
What lights up the Flame Nebula? Fifteen hundred
light years away towards the constellation of Orion lies a nebula which, from its glow and dark
dust lanes,
appears, on the left, like a billowing fire.
But
fire,
the rapid acquisition of
oxygen,
is not what makes this
Flame glow.
Rather the bright star Alnitak, the easternmost star in the
Belt of Orion
visible just above the nebula, shines energetic light into the
Flame that knocks electrons away from the
great clouds of hydrogen
gas that reside there.
Much of the glow results when the electrons and
ionized hydrogen recombine. The above false-color picture of the Flame Nebula (NGC 2024)
was taken in
infraredlight, where a young star cluster
becomes visible.
The Flame Nebula is part of the
Orion Molecular Cloud Complex,
a star-forming region that includes the famous
Horsehead Nebula,
visible above on the far right.
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Note: An APOD editor will review great space images this Thursday night in Houghton, Michigan.