The shockwave was propelled out into the universe by a red supergiant star, which exploded in 2011, 1.2 billion light-years from Earth. The star was about about 500 times the size of the sun.*
The bright flash of the super**va's shockwave — k**wn as the "shock breakout" — is only visible for about 20 minutes, according to current models, so actually seeing it is incredibly difficult.