The beautiful Trifid Nebula
is a cosmic
study in contrasts.
Also known as M20,
it lies about 5,000 light-years away toward the
nebula rich constellation Sagittarius.
A star forming region in the plane of our galaxy,
the Trifid does illustrate three different types of
astronomical nebulae;
red
emission nebulae dominated by
light from hydrogen atoms,
blue
reflection nebulae produced
by dust reflecting starlight, and
dark nebulae where
dense dust clouds appear in silhouette.
But, the red emission region roughly separated into three
parts by obscuring dust lanes is what lends the Trifid its
popular name.
Pillars and jets sculpted by newborn stars, above and right of
the emission nebula's center, appear in famous Hubble Space Telescope
close-up images of the region.
The Trifid Nebula is about 40 light-years across.
Too faint to be seen by the unaided eye, in this deep telescopic view
it almost covers the area of a full moon on planet Earth's sky.