Astrophysicist Stephen Reynolds and his team discovered the youngest Supernova ever seen in the Milky Way. Scientists estimate that supernova G1.9+0.3 is 140 years old, that's 200 years younger than the next youngest known supernova, Cassiopeia A.
"Cas A had been the reigning youngest remnant for so long that it took a while to sink in that we had found something less than half its age," Reynolds said.
If it weren't so obscured by dust, people in the late 1800s would likely have seen G1.9+0.3 appear in the constellation Sagittarius.
As it is, G1.9+0.3—located about 26,000 light-years away—is still expanding at a surprisingly fast rate, and its discovery may pave the way to a greater understanding of exploding stars.