Magnestars Magnestars are neutron stars (which are pretty amazing anyway) with very powerful magnetic fields. The strength of their fields is typically one thousand, million, million times that of the Earth.
At half the distance to the Moon a magnestar's field would wipe the information from the magnetic strips on all the credit cards on the Earth and at 1000km no life would be possible as it would distort the electron clouds of atoms.
BTW Fortunately the nearest magnestar to earth is about 9000 light years away
In August 1998 a burst of x and gamma rays reached the Earth. It was detected by a number of satellites whose counters went off the scale and one the had to shut down to protect itself. It also ionised the the upper atmosphere disrupting long wave communication on the night side of the Earth. This ionisation is something that happens everyday due to similar emissions from the Sun and is why long wave radio communication is better at night than during the day.
Therefore the source of the x and gamma rays did what the Sun does everyday but it was not, like the Sun, about 8 light minutes away from Earth, it was 20,000 light years away.