Magnetars are rotating, highly magnetized neutron stars. They were first observed on August 17, 1997, as a burst of gamma rays and x-rays, lasting about five minutes, and it was so powerful that noticable ionization in the Earth's upper atmosphere was recorded, in amounts that compete with our Sun's radiation during daytime.

These bursts are due to earthquakes, or rather starquakes, on the star's surface due to fluctuations in the extreme magnetic field, causing the surface to crack open and release a shower of high energy particles and gamma rays.

It is thought that magnetars can have a magnetic field perhaps as strong as one million billion times the Earth's.