MELISSA BLOCK, HOST:
Wild splashes of Technicolor - pink and green and red - bathed the sky yesterday in more than half the United States, from Minnesota down to Mississippi. The Aurora Borealis, the Northern Lights, put on a great display unusually far south.
And Robert Moore was among those lucky enough to see it. He teaches physics and astronomy at the University of West Georgia. Robert Moore, where were you? What did you see?
ROBERT MOORE: I was out in our observatory. We have our astronomy lab students come out to do a night observation at least once during the semester. And so, last night we were having one of those observations, looking at some of the wonders that are out there in the night sky.
BLOCK: And what happened? Would did you see?
MOORE: Well, we've got an unexpected one.
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MOORE: What we saw was the whole northern horizon pretty much light up with these gorgeous red curtain of light that stretched from horizon up to about the North Star. So, it was pretty high in the sky.
BLOCK: Wow. Wow. And you've never seen anything like that before?
MOORE: I had not. This was my first experience with an aurora. And, of course, most our students had not, so it brought the observation, as far as other objects, to a complete halt.
BLOCK: Yeah, I bet. And to see if that far south in Georgia, any idea when the last time was that happened?
MOORE: I actually do not know, but it's not a common occurrence. I mean, at 42, this is the first time I've ever seen it.
BLOCK: That must've been something. I've read that to have the pure red, that you saw there in Georgia, is really rare.
MOORE: It is apparently incredibly rare. That takes where the aurora happening very high in the sky. And they're not really fully understood why they glow red. I mean, we know the mechanism, but typically they're green or purple or blue. And we did see shots of green shoot up through the curtain. But I'll also say there was no undulation to it or anything like that. It was just a nice, bright glow that shifted in brightness across the whole field.
BLOCK: How long did the light show last?
MOORE: I want to estimate probably about 20 minutes, because we were delayed for a while.
BLOCK: Yeah. Well, you would want to tear yourself away, for sure.
MOORE: Oh, no.
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MOORE: We were quite happy to stand there and watch until they faded down to the point where you could just barely see it anymore.
BLOCK: You know, the cause of this, the coronal mass ejection, doesn't sound nearly as romantic as what happen. What does happen in one of these light shows?
MOORE: Well, in the coronal mass ejection, what happens is that essentially it's an explosion of the sun. It sends out billions of tons of material off of the sun's surface, flying out through space. And it's traveling several hundred kilometers per second. So, it's traveling really fast, faster than anything here most people would have any experience at.
And so, what happens is, is this is made up of charged particles, which then hit the Earth magnetic field and compress it, and stretch it and make it break. And also, it sends these particles shooting down into the atmosphere. And when they come in contact with oxygen and nitrogen molecules, they ionize it. And then when electrons drop back into these ionized molecules and atoms, they give off light. And that's a very simple explanation for it, but I don't think people really want to get into the equations in math. So...
BLOCK: Well, it works for me.
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BLOCK: And for the Northern Lights to be visible that far south, where you are in Georgia, was it just a really big solar outburst?
MOORE: I - honestly, that's why I wasn't expecting it. I don't think it was really that big of an outburst, just something went right. And these high-altitude red aurora were the result, so I think that had something to do. But it may also be that we did actually take a pretty good impact from the CME, and that just put a lot of energy into the magnetic field.
BLOCK: Robert Moore teaches physics and astronomy at the University of West Georgia. We were talking about the Northern Lights last night that showed up remarkably far south. Robert Moore, thanks.
MOORE: No problem, ma'am.
BLOCK: And if you're hoping to catch the Northern Lights tonight, it might be tough especially in the South. SpaceWeather.com, a website the tracks these things says the geomagnetic storm that caused the lights is settling down. But for people farther north, it says stay alert for auroras.
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MICHELE NORRIS, HOST:
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