One of the most beautiful objects in the northern sky is the Bubble Nebula in the constellation Cassiopeia, the conspicuous “W” in the sky. Inside the nebula shines an extremely hot star, about 400,000 times as bright as our sun. This makes it one of the brightest stars in our Milky Way. Its high-energy radiation heats up the surrounding molecular cloud, creating this beautiful bubble nebula.
Bubble Nebula NGC7635