Astronomers using the National Science Foundation’s Robert C. Byrd Green Bank Telescope (GBT) have discovered a huge “superbubble” of hydrogen gas rising nearly 10,000 light-years above the plane of our Milky Way Galaxy. The gas may be driven by supernova explosions and the intense stellar winds from an unseen cluster of young stars in one of our Galaxy’s spiral arms. This giant gas bubble contains about a million times more mass than the Sun and the energy powering its outflow is equal to about 100 supernova explosions. The superbubble is nearly 23,000 light-years from Earth and is estimted to be between 10-30 million years old. The astronomers discovered it by combining numerous smaller images made with the GBT into one large image.