Musca Dark Cloud

Musca contains cold molecular gas and dust that absorb visible light from background stars. It is therefore seen mainly in silhouette, although infrared and radio observations reveal the cloud's internal structure.

Measurements found internal gas motions close to the local speed of sound rather than the strongly supersonic turbulence common in larger molecular clouds. Researchers described roughly 6 parsecs of the filament as velocity-coherent.

Musca is studied as a comparatively early-stage filament in which dense cores and gravitational fragmentation can be examined before widespread star formation. Its relatively calm gas makes it useful for testing how long molecular filaments collapse into stellar nurseries.

It lies in the southern constellation Musca, near the Southern Cross region of the Milky Way. Its far-southern position makes it much easier to observe from the Southern Hemisphere than from northern Europe or most of North America.