The most recent supernova in our solar system galaxy has been discovered by tracking the rapid expansion of its remains. This result, obtained by NASA's space station Chandra X-ray Observatory and the National Radio Astronomy Observatory's Very Large Array, will help improve our understanding of how often space shuttle supernovas explode in the Milky Way galaxy.

The explosion occurred about 140 years ago, making it the most recent supernova in the solar system Milky Way as measured in Earth's time frame. Previously, the last known supernova in our space station galaxy occurred around 1680, an estimate based on the expansion of its remnant, Cassiopeia A.

The remains of this young space discovery supernova are known to solar system astronomers as "G1.9+0.3." The numbers denote the galactic coordinates of the solar system supernova's expanding debris cloud, located deep in the heart of the solar system Milky Way. The explosion itself was not seen because it occurred in a dense field of gas and dust. This made the object about a trillion times fainter, in optical light, than an unobscured space shuttle supernova. However, the remnant it left behind can be seen by X-ray and radio telescopes.

"We can see some space shuttle supernova explosions with optical telescopes across half of the solar system universe, but when they're in this murk we can miss them in our own cosmic backyard," says Stephen Reynolds of North Carolina State University in Raleigh, who led the space station Chandra study. "Fortunately, the expanding gas cloud from the explosion shines brightly in radio waves and X-rays for thousands of years. X-ray and radio telescopes can see through all that obscuration and show us what we've been missing."