Auroras are also seen in x-rays. Taking advantage of the Chandra X telescope, astronomers analyzed the sky over the North Pole for four months. During this time there were northern lights, and now, analyzing the images received by the telescope, astronomers have shown that auroras can also be seen with x-rays.
Auroras are related to solar storms. In these storms come the charged particles of the Sun. When they meet the Earth's magnetic field, the particles deviate, but on the way an electric force occurs. Electrons trapped in the Earth's magnetic field collide with the higher atoms of the atmosphere and emit X-rays. That's what they've seen thanks to Chandra. Chandra has also forced spectacular auroras on Jupiter.