NGC 7635, the Bubble Nebula in Cassiopeia. The Bubble is approximately 11,000 light years distant, and is approximately 10 light years in diameter. The stellar wind of the massive Wolf-Rayet star BD+602522 is pushing the gas shell of the nebula outward, but the outward movement is being resisted by the nearby dense molecular cloud. This interaction causes the surrounding material to heat up and glow. This image was taken using standard broadband red, green and blue color filters, and as a result has a more normal color appearance than some images of this object taken using narrowband filters.