A huge cloud of expanding supernova debris was found hidden in plain sight

When a massive star explodes at the end of its life, it creates one of the most ostentatious displays in the Universe: a supernova.

This is a colossal release of energy that propels the outer layers of the star outward at speeds of an appreciable fraction of the speed of light. For a brief time, this single object can outshine an entire galaxy of billions of stars.

So you'd think hiding the results of one would be tough. But, it turns out, that can in fact be the case. Astronomers just discove...