Stellar Bubble

This bubble of hot gas is giving birth to new stars in the constellation Scorpius. Known as RCW 120, it's about 5,500 light-years away and spans about 15 light-years. A "hole" at top left appears to be letting some of the hot gas flow out into the surrounding space, which is less dense than the interior of the bubble. The bubble was formed by winds from a hot young star, which piles up material around it, forming a shell. Stars have been born in that shell, where others are still taking shape. [NASA/JPL-Caltech/GLIMPSE-MIPSGAL Teams]