A powerful shock wave traveling through a cloud of gas left by a star’s explosive death has a strange quirk: It’s traveling in the wrong direction, a new study shows.
According to the study, a section of the shock wave collapsed toward the stellar explosion, or supernova, in what the authors call a “reverse shock.”
This nebula, or gas cloud, is one of the closest supernova remnants to Earth, left by a supernova in the constellation Cassiopeia.
Approximately 16 light-years wide, the nebula is made of gas that was expelled both during and before the explosion that ripped apart the original star.
In theory, this shock wave should expand evenly, like a perfectly round balloon that’s continuously inflated by the shock wave from the explosion.
According to theoretical supernova models, Cassiopeia A’s western region has an unusual expansion. In the aftermath of the stellar explosion, something strange happened to the shock wave..