The National Aeronautics and Space Administration said the discovery, made by tracking the rapid expansion of the supernova's remains, will help the understanding of how often supernovae explode in the Milky Way galaxy.

NASA said the supernova explosion occurred about 140 years ago, making it the most recent in the Milky Way. Previously, the last-known supernova in our galaxy occurred around 1680 -- an estimate based on the expansion of its remnant, Cassiopeia A.

Astronomers said finding such a recent, obscured supernova is a step toward making better estimates of how often the stellar explosions occur. That's important, they said, because supernovae can result in the formation of new stars as part of a cycle of stellar death and rebirth. The explosion also can leave behind, in addition to its expanding remnant, a central neutron star or black hole.

The findings are to appear in The Astrophysical Journal Letters.