SIOUX FALLS, S.D. (KELO) — On Thursday night, the skies across South Dakota and many other states were host to spectacular light display known as the Aurora Borealis.
Also called the northern lights, these glowing ribbons of light are the product of massive solar storms which shoot radiation particles across the system.
According to Judy Vondruska, SDSU Senior Lecturer in Astronomy and Physics, these radioactive particles get trapped in the Earth’s magnetic field, spiraling in at the poles where they interact with gasses such as nitrogen and oxygen in the atmosphere, creating the colors we see in the sky.
This interaction takes place high in the sky. Vondruska says the blues and the purples as the radiation interacts with the nitrogen in the atmosphere about 60 miles above the surface. The reds and the greens, she said, typically form above that, around 100-150 miles above the surface.
But how does this radiation reach us, and why was it so intense Thursday?
Vondruska says there is a sort of solar-cycle, with activity on the sun peaking about every 11 years. We are currently approaching one of these peaks, expected to come in 2025. What this means is that while sightings of the Aurora are not typically common in South Dakota, they are going to become increasingly frequent in the next few years.
“Typically you have to be in North Dakota, Canada, Alaska,” said Vondruska. She said we haven’t seen a ton of Aurora activity in South Dakota lately, because we hadn’t been in a strong solar cycle.
With the current level of solar activity, Vondruska says that the South Dakota/Nebraska border is about as far south as the lights will be visible. “Historically, there have been some massive solar storms,” she noted. How massive? “You could see the northern lights as far south as Cuba — they were bright enough that you could read a newspaper at night.”
Such massive solar storms are rare, but they have happened. Even for relatively smaller-scale storms, the effects can go further than lights in the sky. Vondruska recalled one solar storm in 1989 that took out a portion of the power grid in eastern Canada.
“It has an effect on communication; it has an effect on our satellites; it has an effect on the electrical grid — so yes, we worry about this,” said Vondruska. “Solar scientists are always trying to figure out, how can we predict when the next solar storm is going to happen.”
Given notice of a strong solar storm, these days power companies can prepare for surges, while other services such as phone and cable companies can warn customers of potential interruptions. Beyond these precautions though, there’s nothing that can be done to stop a solar storm.
Solar scientists have made strides in predicting some solar events. In the event of a coronal mass ejection, an event it which particles can take up to a few days to reach the Earth, scientists can detect the event ahead of time and give proper warning. This is not always the case.
“It it’s a solar flare, that’s really pure energy,” Vondruska said. “That’s here within minutes. We don’t have a lot of protection or a lot of time to adjust to that.”
Though these massive solar events which cause the northern lights are made up of solar radiation, it does not pose a direct risk to us on the surface, according to Vondruska.
“Typically when we reach solar maximum, there is caution given to whether or not our astronauts go out and do any work outside the International Space Station — we typically will keep that activity low,” said Vondruska. “If you have pilots in aircraft that are flying a lot over the poles during high solar activity, they’ll try to limit that flight time and that exposure.”
These astronauts and pilots take caution due to the increased radiation they may be exposed to while working at high altitudes. For those of us on the surface, Vondruska says our planet’s atmosphere and magnetic field protects us.
While attempting to view the northern lights may seem like an exercise in luck, Vondruska has some tips and resources.
First of all, to have the best chance of seeing the Aurora, you will need to get away from sources of light pollution. This means that if you’re in any metropolitan area that puts off a lot of light, you’ll need to get out of town a few miles.
Since the Aurora spirals out from the pole, you will most likely want to head north out of town. Vondruska says that while you can drive south, you may need to go farther in that direction, as you’ll be attempting to look back north across the island of light pollution you’ve driven away from.
Driving north out of a city like Sioux Falls, Vondruska says you may need only go as far as 2-5 miles.
Of course, the northern lights appear as a result of the solar energy released by the sun, so how can we know which nights the display will appear?
“Here in South Dakota, if you happen to be on Facebook, there’s a group called the South Dakota Aurora Notification Group,” said Vondruska. She also recommended the National Oceanic and Atmospheric Administration’s (NOAA) Aurora tracker, which provides 30-minute forecasts for where and when the lights may be visible.
If you’re viewing the Aurora, Vondruska said they’re often bright enough to capture with your cell phone camera. Her recommendation to set a 10 second exposure to capture more light.
Finishing up the interview, Vondruska left us with one final fact about the Aurora: They’re not solely an earthly phenomena. “We actually see Aurora happen on other planets; Jupiter and Saturn in particular,” she said. “Basically any planet with a magnetic field will experience an Aurora.”