ATLANTA — It's a spectacle most Georgians would need to hop on a plane to see with their own eyes.
The Northern Lights, or Aurora Borealis, were visible all across the Peach State last Friday. In fact, they were seen as far south as the Caribbean, thanks to the strongest geomagnetic storm that hit the earth in more than two decades.
The Space Weather Prediction Center said G5 conditions were reached last Friday night, marking an 'Extreme' Geomagnetic Storm. The K-index reached a level of '9o', which sends visibility of aurora across the contiguous U.S.
Dr. Piet Martens is a Professor of Astronomy at Georgia State University who focuses part of his research on solar storms. 11Alive sat down with him for an in-depth conversation about the Northern Lights' visibility here and why we should be thankful negative impacts were not worse.
Below is a full rundown of that conversation.
Question:
What transpired last Friday?
Martens: "The sun is a very active star. It doesn't seem like that if you look at it from the beach but it actually has a lot of magnetic activity on the surface. And sometimes you get these huge explosions, and masses expel high-energy particles. Most of the time, they go in a different direction, not straight at the Earth, so you don't have to worry about it. You can still look at it through a telescope.
If you get a very strong punch on the nose, then the aurora borealis goes all the way to the south, and you can see it in Georgia. You normally only see it in a narrow band up north and just north of our border in Canada. And Iceland and Northern Scandinavia."
Question:
How rare was something like this that unfolded last weekend?
Martens: "Maybe once per solar cycle. Best, two. And a solar cycle this 11 years. Activity going up and down. So this is rare... Normal Northern lights are not rare at all. I lived in Montana for many years, and we had dozens of them after every winter. Mostly in the winter."
Question:
But the last time that we might have seen the Northern Lights this far south, would that have been, you think, the Halloween storms of 2003?
Martens: "Oh. That's possible. Yeah. Definitely possible."
Question:
But now we had a much different, unique experience on Friday because people had their cell phones that were capable of taking pictures, right?
Martens: "Oh yeah, that too. So everybody has pictures, and you can find many great pictures online. Also from the South, you also people in New Zealand who have seen the sudden aurora, which happens at the same time."
Question:
And let's talk a little bit more about these pictures. I mean, it was easier to see the northern lights and the aurora on your phone versus your eye. But if we look at some of these pictures behind us, many of the colors people saw were kind of hues of red and green. What are the different colors when you're seeing the northern lights or Southern lights? What is happening with the chemistry in the outer atmosphere of the Earth?
Martens: "So what happens is very high energy particles, electrons fall on, they don't fall. They enter the Earth's atmosphere along the magnetic field lines near the poles where they are open, where they can actually enter the doors open there. Then, they hit our atmosphere, which mostly consists of nitrogen and oxygen. And those high-energy electrons will then ionize those molecules there. So, either the oxygen or the nitrogen and as they are ionized, then they recombine again and they emit light photons, and those photons come in specific wavelengths, specific colors. So that's why you see the blue, which I think is nitrogen, and green, green is the most dominant one. That's oxygen. But there's also a little bit of red, from the oxygen all the way below, you get the ultraviolet, which comes from nitrogen."
Question:
Do you feel like any of the photos that people took were used as, say, citizen science? Do you think any research projects are constantly ongoing when the sun gets into these active periods of its solar cycle?
Martens: "Yes. The northern lights and satellites are still being investigated a lot because we don't understand exactly how they work. We get we have the big picture, these high energy particles, and it's caused by the sun. We all know that. But where the high energy particles come from are actually different regions that can come straight from the sun. It can be because of the reconnection of the magnetic field by the impact of ejection from the sun on the Earth's magnetic field, which means you compress it, and that generates an electric field that generates high-energy particles. Or it can be electrons that were already stored in the Earth's magnetosphere, where we call them an alum belt. And then they're released, as it were, near the poles. And the same thing, high energy particles. Or you can have a connection with a coronal hole, which is actually a dark spot on the sun in X-rays. And high, high-energy wind comes from there. And that wind can also carry high-energy particles. So many sources."
Astrophysics is complicated.
"Yeah, it always is."
A lot more complicated than just forecasting the weather in the troposphere.
"Well, it's actually similar when we talk about space weather. Yeah. We try to forecast that because it can have many negative influences somewhere."
Question:
Let's talk about those negative impacts. I mean, when you have a storm of that magnitude, it's not just creating the auroras. It causes negative problems for power grids. What kind of problems can we see from a storm of that magnitude?
Martens: "Okay, many, let me start with astronauts outside the Earth's magnetic field. And the, for example, they've gone back to the moon. They can be impacted by high-energy radiation, which can cause cancer. And in the worst case, just kill you right away. So we want to protect those astronauts. You can't stop the radiation, but you can tell them to go inside the spacecraft, which gives it a huge protection by a factor ten about they might even be able to hide behind let shields if they take them in the spacecraft, just like you do at the dentist. So this is important for going back to the moon and for going to Mars, you know, long term. And this is actually my research that I work on. I'm trying to predict those events."
That's your research. Yeah. Trying to predict when the solar storms will happen.
"Yes. And when they will impact."
Question:
And how quickly after the sun releases. One of those we call them CMEs. How long does that take versus a solar flare to reach the Earth? What's the difference?
Martens: "A solar flare is the emission of light energy. X-rays mostly. And those X-rays travel with the speed of light. So they're here in eight minutes. But they don't do much. They're not very negative, so we don't have to worry about it. But we can see in the morning the CME squirrel mass ejections, magnetic field and plasma. Not your blood plasma, but ionized material. They take from 1 to 4 days, and the fastest ones are the most dangerous. They have the most energy. So you get a one-day warning if you just constantly look at the sun. That's very helpful."
Question:
We know the sun is in this very active period. Is another solar storm that reaches G4 or G5 possible?
"Oh, absolutely. Yeah. It's like, is a tornado possible? Yeah. But can you say when and where? No."
Question:
So, possibly another solar storm of that magnitude could impact the Earth, but also possible that the trajectory might miss us altogether?
"Yes. Or it may not happen. Such a big event."
So cross your fingers, you know. Or if you're talking about the power grid, do not.
"This one was actually pretty benign. We had beautiful auroras, but there hasn't been much negative impact on Earth because, as you mentioned, it can, in the worst case, power; a powerful solar storm can knock out the power grid. And there has been a study that started under... Bush was continued under Obama. And so they wanted to know the worst case and how often it could happen. Right. And the worst case is that the entire U.S. electric power grid gets knocked off. Now, that would be a total disaster. They're talking about $10 trillion of damage, monetarily. But that's not the big thing. It's what happens to humans. Imagine Atlanta sitting in the dark in the middle of summer. You have no air conditioning. You have no Marta. You have no light. You have no elevators, and you have no fridge. So that's truly awful. And depending on how long it lasts. And I think that works with your car. You best get in your car and get out of here."
So that's why that's so important. I know makes pretty pictures in the sky. But it's important for your research to study, right. The sun and solar storms and and the solar wind and how things move.
"If we can make the right predictions, we can save a lot of money and even life."
Question:
What excites you about the number of people who got to experience science on Friday night?
Martens: "I think that's great. And that's exactly what I tried to do. I teach one undergraduate class in astronomy, and I try to convey to my students how beautiful the universe is and all these great things you see. And I'm not asking them to memorize a lot of stuff. It's more important that you actually see pictures of those moons and realize how different they are. So this is a free demonstration that I'd love to do in my class. And interest people now may also be a warning that, hey, bad things could happen to not a good thing with space weather is that it's a bipartisan issue, and I'm glad of a dose. Fortunately, both parties agree we really should get ready for that."