What causes the Northern Lights?

The aurora borealis, the well-known but fickle lights in the sky, have long been a mystery to me. Even after seeing them in the flesh and doing some research, I still only grasped the most basic principles on what causes the lights.
I’m happy to say that after extended reading, I, like anyone that isn’t a chemistry or physics major, will probably never have a full understanding of what the northern Llghts are. But from one lay-person to another, just what are the northern lights?
The story begins 93 million miles away on the sun. The sun, a massive, gurgling swirling mess of energy is constantly sending energy our way, with particles all across the spectrum, most of which is outside the range which we can perceive with our eyes. So amidst this wild-wild-west of chemical activity on the sun, every once in a while we get a solar flare. On the surface of the sun, there are large prominences, or loops of magnetic energy. When they intersect, there is a massive explosion that radiates energy toward the earth.

Then, two days later, this blast reaches Earth. It actually affects every level of our atmosphere from the ionosphere to the mesosphere. Again, this interference is imperceptible because the waves extend beyond the range of what our eyes can detect.
But it is the solar flare interfering with the magnetosphere that gives us that glorious aurora. So the energy from the sun, in the form of electrons is scattered across the magnetosphere, which is filled with oxygen and nitrogen particles. When the electrons collide with them, they are energized, or excited momentarily. When an atom is excited and then returns to a normal state from an excited state, that energy, of course, does not disappear. In this case it is released in the form of photons, or small bursts of light. Depending on what element is releasing photons, and how charged it was is what determines the color that is released that be witness. Science! Now you know, so tell a friend! For a pretty cool video from the University of Oslo on how the Aurora works, check this out!
For some ideas one good places to catch a glimpse, check out our blog on “The Best Places to View the Lights”!