Astronomy Picture of the Day

Explanation: This cosmic expanse of dust, gas, and stars covers close to 3 degrees on the sky in the heroic constellation Perseus. Right of centre in the gorgeous skyscape is the dusty blue reflection nebula NGC 1333, about 1,000 light-years away. At that estimated distance, the field of view is about 50 light-years across. Next to NGC 1333 is the reddish glow of shocked hydrogen gas created by energetic jets and winds from stars in the process of formation. Other reflection nebulae are scattered around, along with remarkable dark dust nebulae. Near the edge of a large molecular cloud, they tend to hide the newly formed stars and young stellar objects or protostars from prying optical telescopes. Collapsing due to self-gravity, the protostars form around dense cores embedded in the molecular cloud.