This planet’s auroras are a spectacular sight, but you’ve probably never seen them quite like this. What you see below is a view of them as seen by the European Space Agency’s Integral space observatory, which captured how they look as an X-ray.
The ESA explains what you can see:
As energetic particles from the Sun are drawn along Earth’s magnetic field, they collide with different molecules and atoms in the atmosphere to create dynamic, colourful light shows in the sky, typically in green and red. But what may be less well known is that auroras also emit X-rays, generated as the incoming particles decelerate.
The data is actually a by-product of Intergral scanning diffuse cosmic X-ray background from supermassive black holes. But it does that by looking at the night sky with and without the Earth in the way, so it can compare the two results to understand background X-ray levels.
This time round, in November of last year, the Earth didn’t play ball: the X-ray emissions from the aurora drowned out by every other signal completely. Ah well — our gain. [ESA]