View your list of saved words. (You can log in using Facebook.)
Dark nebula in the Crux constellation (Southern Cross). It reduces the brightness of stars beyond it by 1–1.5 magnitudes. Easily visible against a starry background, it is probably about 550–600 light-years from Earth and 20–30 light-years in diameter. It figures in legends of peoples of the Southern Hemisphere and has been known to Europeans since c. 1500. The Northern Coalsack, in the constellation Cygnus, is similar in nature and appearance but somewhat less obvious.
This entry comes from Encyclopædia Britannica Concise. For the full entry on Coalsack, visit Britannica.com.
Seen & Heard
What made you look up Coalsack? Please tell us what you were reading, watching or discussing that led you here.