Unraveling the Mystery of the Brightest Gamma-Ray Burst in History.

Ultraluminous X-ray sources (ULXs) are breaking the Eddington limit, which determines how bright something of a given size can be. New observations from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) confirmed that one particular ULX, called M82 X-2, is definitely too bright. M82 X-2 is an object known as a neutron star, and the research team thinks that the intense magnetic field of the neutron star changes the shape of its atoms, allowing the star to stick together even as it gets brighter and brighter.