The Shark Nebula

About This Photograph

In the far northern constellation of Cepheus, the Shark Nebula keeps watch over the region surrounding the North Star. This dusty region is seen mostly through a process called photoluminescence. The dust particles in the cloud absorb high-energy light from the nearby bright stars, and then re-emit some of this energy as as reddish light, called "extended red emission." In the shark's "head," the dust is dense enough to become opaque and almost as dark as the background beyond. In two places, near the shark's "neck," bright stars are still embedded in the cloud, and the dust surrounding them nearby reflects their bluish tint.