In this artist's animation, the December 27, 2004 blast from SGR 1806-20 was the brightest outburst ever seen coming from an object beyond our own Solar System. Even at 50,000 light-years away, its burst of gamma rays and X-rays disturbed the Earth's ionosphere, causing a sudden disruption in some radio communications. A magnetar is a superdense neutron star with a magnetic field thousands of trillions of times more intense than that of the Earth. Scientists believe that SGR 1806-20's giant burst of energy was somehow triggered by a "starquake" in the neutron star's crust that caused a catastrophic disruption in the magnetar's magnetic field. The magnetic disruption "boiled off" particles from the star's surface into a rapidly-expanding fireball.
Credit: Trent L. Schindler / National Science Foundation