UAF researchers explain science of the aurora

By  | 

FAIRBANKS, Alaska - The aurora activity tonight is expected to be high -at a level 5 out of 9.
But what does that mean, and how do they know that?
We talked to scientists at UAF to help us understand where those numbers are coming from and how the aurora is predicted.
Katie Luper; Reporting>>: As Alaskans, we're lucky to see the aurora. You might have heard it's caused by solar winds hitting the upper atmosphere, but it's a lot more complicated than that. Charles Deehr, a professor emeritus of physics, says think of it like a big generator that...
Charles Deehr; Professor Emeritus of Physics>>: "Transfers the energy from the solar wind to the earth's magnetic field and drives the current along the magnetic field lines, just like the power lines at Golden Valley."
Katie Luper; Reporting>>: The Earth is a giant magnet. The lines of the magnetic field flow out the top of one pole loop around and into the other creating a shield - kind of shaped like a donut that keeps us protected from sun sending...
Charles Deehr; Professor Emeritus of Physics>>: "This current, a million amperes, is coursing through the atmosphere 100 kilometers above the Earth, and causing the aurora."
Katie Luper; Reporting>>: But what causes the different colors?
Jason Ahrns; Graduate Student & PhD Candidate>>: "The particles coming down from the solar wind, they're electrons and protons. They come down and eventually they hit some particle in Earth's atmosphere, and that's what creates the glow. But what particle they hit is what color glow we get. So in the earth's atmosphere, they're this type of gas down low, nitrogen, and then above that, there's some oxygen. And if it hits an oxygen it's going to make red, or if it hits oxygen further down it's green, and if it gets all the way down to the nitrogen, it makes that pink bottom you sometimes see."
Katie Luper; Reporting>>: Now, how do they predict the aurora? Well, the northern lights produce electrical currents in the atmosphere...
Charles Deehr; Professor Emeritus of Physics>>: "Those are measured by magnetometers around the world. And we get what's called a worldwide or planetary intensity."
Katie Luper; Reporting>>: Those are simple instruments on the ground measuring the disturbance in the Earth's magnetic field. They also use models to understand the current and future state of the space weather environment. UAF started forecast research in '94, but funding ran out in 2007.
Charles Deehr; Professor Emeritus of Physics>>: "It's been, since then, the aurora forecast is on an automatic feed from the space weather center in Boulder, Colorado."
Reporting from UAF, I'm Katie Luper.