The Bubble Nebula (NGC 7635) is a striking emission nebula located roughly 7,100 light-years from Earth in the constellation Cassiopeia. Its distinctive bubble-shaped structure is formed by the powerful stellar wind of the massive O-type star BD+60°2522, which pushes surrounding gas outward to create an expanding shell. Although the bubble itself spans about 7 light-years across, it is embedded within a much larger complex of glowing hydrogen clouds and dark interstellar dust. The Bubble Nebula is an active region of star formation and is often photographed alongside the nearby open star cluster M52 (not shown in this image), creating one of the most recognizable deep-sky scenes in the northern sky.