Explanation: What created this huge space bubble? Blown by the wind from a star, this tantalizing , head-like apparition is cataloged as NGC 7635, but known simply as the Bubble Nebula . The featured striking view utilizes a long exposure to reveal the intricate details of this cosmic bubble and its environment. Although it looks delicate, the 10 light-year diameter bubble offers evidence of violent processes at work. Seen here above and right of the Bubble 's center, a bright hot star is embedded in the nebula's reflecting dust. A fierce stellar wind and intense radiation from the star , which likely has a mass 10 to 20 times that of the Sun , has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud . The intriguing Bubble Nebula lies a mere 11,000 light-year s away toward the boastful constellation Cassiopeia .

Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)