When given a chance, Moscow is allowed to see a light show in the sky. If conditions allow it, the Aurora Borealis or the Northern Lights can be seen in Northern Idaho.
Professor of Astronomy & Planetary Science Jason Barnes studies planetary systems.
“The aurora is ultimately a phenomenon that occurs at the top of Earth’s atmosphere,” Barnes said. “The reason it occurs is that charged particles, primarily protons (and) electrons from the sun’s solar wind get trapped in Earth’s magnetic field.”
Barnes stated that charged particles can’t move perpendicularly across the magnetic field lines due to the shape of the Earth’s magnetic field. This results in most particles staying in space, known as the Van Allen radiation belt.
“If the energy particles have enough energy, they will spiral all the way down, and they will slam into Earth’s atmosphere,” Barnes said. “When they do that, they knock electrons around in the molecules in Earth’s atmosphere, and when those electrons recombine to the atoms, it causes the gases to glow in the Earth’s upper atmosphere.”
Matthew Hedman, associate professor in astronomy & planetary science, discussed the sun’s role in creating the aurora.
“On top of regular weather, which is clouds and rain, there’s also what’s called space weather, which is basically how much solar wind is coming,” Hedman said. “When you throw a lot of protons and other things onto the earth, it can distort the magnetic field that affect things, allowing the aurora to be visible further from where it can normally be seen, including in certain conditions up all the way down to Moscow.”
Hedman stated that it used to be hard to predict when the sun would have coronal mass ejections, resulting in auroras being seen further away from the pole.
Barnes discussed the instruments and spacecraft used that help measure solar winds.
“ACE, the Advanced Composition Explorer and DSCOVER, the Deep Space Climate Observer, which hangs out between Earth and the sun, are actively monitoring the state of the solar wind as it evolves,” Barnes said. “We can also just look at the sun and from the Earth’s orbit and see large prominences or flares or coronal mass ejections that we know will drive the aurora.”
Barnes explained that part of following the lights is the KP index, the measurement of the intensity of the solar wind within a range of zero to 10.
“When the KP factor is high that means that there’s a lot of solar activity and then we would expect an intense aurora, possibly with coming down to very low latitude,” Barnes said. “When the KP index is relatively low, we expected, the aurora will sort of be huddled around the pole and perhaps be less intense.”
Hedman stated that a KP value of four to five would be visible in Moscow, where the normal KP value is one to two.
Barnes was able to advise on how long the auroras can be seen.
“They can be somewhat ephemeral, so they can come and go, 10s of minutes, a half-hour, an hour- you can sort of lose one and gain another one in a different place,” Barnes said. “When you do see one, you can text your friend and they have time to go out and see it, unlike a meteor or something which can take only three seconds.”
Hedman stated that there are plenty of sites that have information on space weather. The Space Weather Prediction Center, spaceweather.com and spaceweatherlive.com are some he suggested.
Daniel V. Ramirez can be reached at [email protected] or Twitter @DVR_Tweets