clipped from: www.usnews.com   
The young remains of a supernova, known as G1.9+0.3, give astronomers a rare opportunity to observe star formation early in the process.

According to calculations, the Milky Way should contain the remnants of 10 supernovae, but one hasn’t been seen since 1680, when a star went out in a blaze of glory and left behind the remnant called Cassiopeia A.

So, astronomers have been wondering, what is up with that?
Relief came yesterday, when scientists reported they found supernova remains that appear to have been hiding behind a thick veil of gas and dust for 140 years. They are the youngest observed so far in the Milky Way and the first example of a "missing population" of young supernova remnants.

In addition to enriching the material between stars with heavy elements, supernovae stir up that material through the shock energy of the explosion. This is thought to help trigger the process of star formation in interstellar clouds of gas and dust. Many astronomers believe our own Solar System is the result of such a supernova shock.