In silhouette against a
crowded star field toward the constellation Scorpius, this dusty
cosmic cloud evokes for some the image of an ominous dark tower.
In fact, clumps of dust
and molecular gas collapsing to form stars may well lurk within the dark nebula, a
structure that spans almost 40 light-years across this gorgeous telescopic portrait.
Known as a cometary globule, the
swept-back cloud, extending from the lower right to the head (top of the tower)
left and above center, is shaped by intense ultraviolet radiation from
the OB association of very hot stars in NGC 6231, off the upper edge of the scene.
That energetic
ultraviolet light also powers the globule's bordering reddish glow of hydrogen gas. Hot stars embedded in
the dust can be seen as bluish reflection nebulae.
Image Credit & Copyright: Don Goldman
