Supernova's leftovers may hold super-dense star.

The remnants surrounding the supernova leftovers of Cassiopeia A may contain a highly magnetized neutron star, or magnetar, and quantum activity never seen before. The first-ever measurement of the polarization of X-rays around a magnetar showed that lower energy X-rays were polarized at 180 degrees to the high-energy X-rays. "Photon metamorphosis," an element of quantum electrodynamics, may be able to explain the weird behavior of X-rays around magnetars. The study of neutron stars helps scientists better understand the physics of matter in conditions that couldn't ever be simulated ever on Earth, meaning it adds to our understanding of the universe's beauty and diversity.