What Happens When ‘The Sun Throws A Glitter Bomb’

FLORA LICHTMAN: This is Science Friday. I’m Flora Lichtman. Every so often, people living in the upper latitudes get a celestial treat, the Aurora. It’s also known as the Northern or Southern Lights, depending on your hemisphere.

But last year, something unexpected happened. Aurora chasers in Alberta, Canada saw a weird thing in the sky, a purpleish streak, maybe a kind of Aurora. And they named it Steve. Of course they did.

My next guest helped to create an app that connects observations made by citizen scientists with space weather researchers hungry for Aurora data. It’s called Aurorasaurus. Joining me now is Dr. Liz MacDonald, space plasma physicist at NASA and founder of Aurorasaurus.org Welcome.

LIZ MACDONALD: Hi, thanks for having me.

FLORA LICHTMAN: What is Steve?

LIZ MACDONALD: So Steve is a great story. It’s something that was observed across Alberta, Saskatchewan. And it was given a different name initially. It’s a very thin, purplish kind of arc that can go across the sky in an east-west direction.

FLORA LICHTMAN: It looks more like a Francesca to me.

LIZ MACDONALD: And it sometimes has a little bit of green to it as well. And it’s quite a bit further south than where most of the Aurora occurs. And people who are enthusiastic Aurora chasers, just like eclipse chasers, they actually captured it when they were out looking at Aurora. That was in Canada, much further north. And they said, what is this thing?

And, initially, it had a different scientific name that myself and other scientists do not think is accurate for it. And so, through citizen science projects, we’ve been connected to some of these enthusiast groups that are organized on Facebook and Twitter. Alberta Aurora Chasers is the one that discovered this phenomenon. And we had conversations with them about how this is not likely to be what the common name was, which was a proton arc.

FLORA LICHTMAN: So they, basically, the Aurora chasers had identified it as a proton arc and connected with you guys and then found out that, no, it’s not a proton arc. It’s something different.

LIZ MACDONALD: Yeah, yeah, they connected with our team at Aurorasaurus and also scientists at the University of Calgary. And they just came up with a new name for it. It’s actually based on an animated kids movie from Canada, where some characters don’t know what something is. It’s like different animals. And they– oh, let’s just call it Steve.

And so this group is really fun. And they said, let’s call it Steve for a while and collect more observations. And that’s really where this became really exciting to document, that Steve is actually not a one-time thing. It’s a scientific phenomenon that can be documented in a rigorous way through citizen science and further investigated.

FLORA LICHTMAN: Is Steve an Aurora, though? What is Steve?

LIZ MACDONALD: So we are still working to figure out what is causing it. It is a long way further south than most of the normal Aurora. And it’s probably excited by light. Most is excited by particles from way further out in space, following the Earth’s magnetic field lines, and hitting the upper atmosphere, and causing some light.

And so there are a couple that could be happening with Steve. Or it’s possible that the upper atmosphere itself is chemically exciting some of the light here. And that’s something that we’re still piecing together from the satellite observations and some of these really interesting DSLR camera observations to further understand, as well as other ground-based camera observations, scientific observations.

FLORA LICHTMAN: Tell me about this. Did DSLRs, did, basically, citizen scientists help find it?

LIZ MACDONALD: Mm-hm.

FLORA LICHTMAN: Was it in the sky before and just we didn’t see it because we weren’t looking in the visible range or something?

LIZ MACDONALD: We’ve been looking in the visible range, but not in this location, which the technical term is sub-auroral. But really what this means is across the US border kind of latitudes. And the scientists missed it largely. Some people had seen it. But it hadn’t been published that we know of yet.

FLORA LICHTMAN: Wow.

LIZ MACDONALD: And, yeah, and it’s pretty obvious in a DSLR camera. And there are other cameras across Canada. There is a great network of auroral cameras. But they’re generally further north because that’s generally where the Aurora is.

And now, the sun’s activity actually drives Aurora. And it gets more active every 11 years. And so the last few years have been more active. More Aurora has been seen at these more southern latitudes.

And now people have better cameras. They have smartphones. They have Facebook and Twitter. And so all of these things together have combined to really help us connect in unique ways and improve our understanding of the system and make a discovery, really, with people’s help, for a much better understanding of this rare kind of Aurora.

FLORA LICHTMAN: That’s cool. So is there a simple way to describe how an Aurora is formed?

LIZ MACDONALD: The normal Aurora, as I said, is driven by the sun, starts up from the sun. One way I like to describe it is thinking of a [INAUDIBLE] cluster of charged particles coming from the sun. And–

FLORA LICHTMAN: A what of charged particles? I think we may have lost you for a second.

LIZ MACDONALD: A glitter bomb.

FLORA LICHTMAN: Oh, I’m so glad that we asked. A glitter bomb.

LIZ MACDONALD: But the glitter is actually all invisible until the very end of this chain reaction that causes the Aurora. And it travels an enormous distance. It travels 93 million miles out from the sun in all directions, and sometimes hits towards Earth, where it interacts with the Earth’s magnetic field region. And there, it gets really complicated as far as how the interaction occurs. And, eventually, that energy is released in an oval shape at the high latitude regions, where it then creates the light of the Aurora and all of this beauty and dynamics that you can see.

FLORA LICHTMAN: Why does it only happen at the poles?

LIZ MACDONALD: So that’s because of the way that the Earth’s magnetic field is largely shaped like a dipole magnet. But the dipole actually gets stretched away from the Earth-sun line because the Earth is sitting in the flow of the solar wind, streaming past us at a million miles an hour. And so all this glitter is coming towards the Earth’s magnetic field region, and streaming past us, and is processed through the Earth’s magnetic field region, and ends up stimulating Aurora from regions closer to Earth that are still a long way away, hundreds of thousands of miles, and at these high latitude field lines.

FLORA LICHTMAN: Before we let you go, are there any big Aurora unsolved mysteries, I guess besides Steve?

LIZ MACDONALD: There are a lot. As I said, a lot of the processes are happening from starting from hundreds of thousands of miles away. And, actually, this dipole magnet of the Earth’s magnetic field really stretches very dynamically and very quickly. And that’s what causes most of the Aurora to be so active. And there’s a lot of that– specifically how it connects way far out in space– that is very difficult to study from the number of spacecraft that we have in those regions.

FLORA LICHTMAN: I’m really glad that you gave us the glitter bomb analogy. I will never look at an aurora the same way. Thank you, Liz MacDonald.

LIZ MACDONALD: Thank you very much. And thanks to all the citizen scientists who have been contributing to Aurorasaurus and other projects like that.

FLORA LICHTMAN: Liz MacDonald is a space plasma physicist at NASA and founder of Aurorasaurus– Aurorasaurus.org. Resource And you can download the Aurorasaurus app, too.

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