Bad Astronomy

What Causes an Aurora?

aurora
A curled aurora, due to a winding of Earth’s magnetic field.

Photo by David Cartier

I write a lot about aurorae, the lovely and eerie glowing lights at extreme latitudes caused when subatomic particles from the Sun are channeled down into the atmosphere by Earth’s magnetic field.

Whenever I do I always wind up having to write a brief explanation of how they work; that’s the responsibility of a science writer.

But my burden is now eased a bit thanks to this well-done video giving a solid overview:

What I like about the video is that it covers the basics without giving too much detail or worrying over distracting side issues. And I have all those covered in earlier posts! So, for your brainy pleasure, here is more detail on …

just why the particles cause the air to glow;

why the aurora glows red, green, purple and sometimes even pink

what an aurora looks like from space;

what they look like from the space station;

what they look like when you’re directly underneath (called a corona); 

how aurorae move in real time;

how this all depends on the 11-year solar sunspot cycle;

how solar flares are classified;

and how solar storms can cause a lot of havoc on Earth.

In fact, gathering all these links in one place will make my life a lot easier next time I post a gorgeous aurora time-lapse!

My thanks to David Miles, part of the Investigations of Cusp Irregularities sounding rocket program, who sent me some links about the ICI-4 rocket campaign, which led me to the video.