Coalsack Nebula

The Coalsack Nebula, also called the Southern Coalsack or just the Coalsack, is a dark nebula. You can see it without a telescope as a dark patch that covers part of the Milky Way. This dark area looks east of Acrux (Alpha Crucis), the brightest star, in the constellation of Crux.

Dark nebulae such as the Coalsack are clouds of dust and gas in space. They block light from stars behind them, which makes them look dark in the night sky. The Coalsack Nebula is one of the easiest dark nebulae to recognize because you can see it with the naked eye.

The Coalsack is part of the Milky Way, our home galaxy. It helps astronomers learn about how stars form and how space is filled with different kinds of matter. Looking at the Coalsack can be a fun way to explore the night sky and learn about the many things that exist far above us.

General information

Long ago, people called any dark cloud in the night sky a coalsack. The Coalsack Nebula got its name in 1899 from Richard Hinckley Allen. He also named the Northern Coalsack Nebula.

The Coalsack Nebula is big. It covers almost 7° by 5°. It reaches into the nearby star groups Centaurus and Musca. In Australian Aboriginal astronomy, the Coalsack looks like the head of the emu in the sky to many Aboriginal cultures. In Inca astronomy, people called this nebula Yutu, after a bird from South America called a Tinamou.

In popular culture

The Coalsack Nebula has appeared in stories and books. In Kenji Miyazawa’s Night on the Galactic Railroad, the Coalsack is a mysterious empty space that a character sees.

The Coalsack Nebula is also important in science fiction books by Jerry Pournelle and Larry Niven. In stories like The Mote in God's Eye, the Coalsack helps create the setting for a faraway planet named New Caledonia.