Saturday night was such a wonderful event! Sunday, I had registered for the Tromsø University Museum Aurora Borealis tour. It turned out I was the only one, so the guide and I had a great time talking about all sorts of science geeky things! He gave me a book from the university about the Northern Lights, and also about the other beautiful lighting that they get way up there. We watched a 23 minute video of the light show. He thought I'd get bored, silly man. I bought a copy afterwards in the museum shop. The photographer, Bjørn Jørgensen, put a shorter version here on Vimeo. (I highly recommend that you watch it!)
I'll sprinkle in the pictures that our tour guide, Terjes Furnes, took Saturday night and e-mailed us.
So, what was the biggest Northern Lights show that we know about? It was in Aug-Sep 1859, the biggest geomagnetic solar storm on record. It was so big that it could be seen all the way down to Cuba. Gold miners in Colorado thought it was morning and starting cooking breakfast! But light wasn't all there was - it was so powerful that it knocked out telegraph communications, shocking operators and maybe even melting copper lines. As far as science goes, though, two independent astronomers observed a big solar flare 18 hours before the huge Aurora, and thought, "Hmmm..." It is called the Carrington Event sometimes.
It's cool that before then, scientists often thought the Northern Lights started at the Earth and went up. Maybe involving electricity (when that was first invented) and electrical discharges in gasses of low pressure. Samuel von Triewald used a glass of evaporating aquavit, shining a light through a prism and then the alcohol, to create "all the phenomena associated with the northern lights in a dark room". Or maybe something about reflections from the infinite snow-covered surfaces could explain it, or giant schools of shiny herring, reflecting up into the sky. Getting a little earlier, and more fanciful, you can see whether people were optimistic or pessimistic by how they explained them. In Canada, they were dancers, while in Greenland, they were still-born babies throwing a walrus skull around. Or how about the churches' stories that they were evil omens, and you should give the church more money to stop the famine or war that was foretold? They could be the dresses of old virgins who died and went to the Northern Lights. One of my favorites is from Finland, where there is a magic fox. His tail brushes against the snow and bushes as he runs, throwing sparks up into the air! Another one involves swans flying too far north and getting stuck in the freezing sky.
You've seen the Marvel movies with Thor, right? About how Heimdall is standing on the bridge between all the nine realms, protecting the Earth from the giants? The bridge is Bifrost, and is supposed to be tri-colored in the old Norse tales, so maybe it refers to the Northern Lights. Another tale from the Norse Edda has to do with the beautiful maiden Gerd Gymesdatter ascending from the sea, making light shine over the land and sea.
Our tour guide told us that the Northern Lights come in three colors, green, pinky-red, and blue-purple. They also can be very slow or they can be dancing the light fantastic. We saw mostly green, with a hint of red sometimes. They were slow enough for us to take good pictures, until the very end of the evening, when they started moving and curling as if they were happy. Getting back to the geeky science stuff, you have to wonder why green? Why red? And how high are they? According to the charts in the museum, they are green or red at different altitudes. As the charged solar particles follow the Earth's magnetic field lines and collide with oxygen or nitrogen, the molecules are excited by the impacts. They release that energy as light quanta which we see as the Northern Lights. This all happens from 110 km up to 200 km, on average, but can go down to 80 km or up to 500 km. An online article explains where the three colors come from, both in terms of atoms and by altitude. It has to do with the density of the atmosphere and the varying composition as it goes up.
But the Finnish burning river Rutja that divides the realm of the living from that of the dead has more appeal!
So, what was the biggest Northern Lights show that we know about? It was in Aug-Sep 1859, the biggest geomagnetic solar storm on record. It was so big that it could be seen all the way down to Cuba. Gold miners in Colorado thought it was morning and starting cooking breakfast! But light wasn't all there was - it was so powerful that it knocked out telegraph communications, shocking operators and maybe even melting copper lines. As far as science goes, though, two independent astronomers observed a big solar flare 18 hours before the huge Aurora, and thought, "Hmmm..." It is called the Carrington Event sometimes.
It's cool that before then, scientists often thought the Northern Lights started at the Earth and went up. Maybe involving electricity (when that was first invented) and electrical discharges in gasses of low pressure. Samuel von Triewald used a glass of evaporating aquavit, shining a light through a prism and then the alcohol, to create "all the phenomena associated with the northern lights in a dark room". Or maybe something about reflections from the infinite snow-covered surfaces could explain it, or giant schools of shiny herring, reflecting up into the sky. Getting a little earlier, and more fanciful, you can see whether people were optimistic or pessimistic by how they explained them. In Canada, they were dancers, while in Greenland, they were still-born babies throwing a walrus skull around. Or how about the churches' stories that they were evil omens, and you should give the church more money to stop the famine or war that was foretold? They could be the dresses of old virgins who died and went to the Northern Lights. One of my favorites is from Finland, where there is a magic fox. His tail brushes against the snow and bushes as he runs, throwing sparks up into the air! Another one involves swans flying too far north and getting stuck in the freezing sky.
You've seen the Marvel movies with Thor, right? About how Heimdall is standing on the bridge between all the nine realms, protecting the Earth from the giants? The bridge is Bifrost, and is supposed to be tri-colored in the old Norse tales, so maybe it refers to the Northern Lights. Another tale from the Norse Edda has to do with the beautiful maiden Gerd Gymesdatter ascending from the sea, making light shine over the land and sea.
Our tour guide told us that the Northern Lights come in three colors, green, pinky-red, and blue-purple. They also can be very slow or they can be dancing the light fantastic. We saw mostly green, with a hint of red sometimes. They were slow enough for us to take good pictures, until the very end of the evening, when they started moving and curling as if they were happy. Getting back to the geeky science stuff, you have to wonder why green? Why red? And how high are they? According to the charts in the museum, they are green or red at different altitudes. As the charged solar particles follow the Earth's magnetic field lines and collide with oxygen or nitrogen, the molecules are excited by the impacts. They release that energy as light quanta which we see as the Northern Lights. This all happens from 110 km up to 200 km, on average, but can go down to 80 km or up to 500 km. An online article explains where the three colors come from, both in terms of atoms and by altitude. It has to do with the density of the atmosphere and the varying composition as it goes up.
But the Finnish burning river Rutja that divides the realm of the living from that of the dead has more appeal!
We saw some great northern lights in Iceland, also. Amazing phenomena.
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