Aurora hunting at the north end of North

For as long as I can remember, the number one thing on my mental list of things I need to see in the world was the aurora borealis. With the solar maximum coming to an end, I couldn’t imagine waiting another 10 years for a good sighting of the aurora, so I planned a trip early this spring. Happily, since I am living in Switzerland now, I could easily make it up to Norway, one of my favorite countries.

Tromsø, Norway

Tromsø is at 70° North, but it is quite big and easy to get to. I flew in via Oslo. It took 4 hours of flying time from Zürich, basically all of it straight north. On a map, the mountains around Tromsø don’t look like much, only 800-1000 meters above sea level. But 1000 meter peaks are amazingly beautiful when they jut right out of the sea. The city is on an island, the island surrounded by fjord and beyond, these peaks jutting out of the ocean. Exploring around town, I was surprised to find that the streets were paved with ice! No joke. A thick layer (3-4 inches) of ice covered almost every surface, streets, sidewalks, driveways. They had carved holes in the ice for the drains so that water could drain off the street. Add a bit of gravel to the ice and the cars can drive around fine, no chains required. Walking is a bit more of an issue, either you go very slow, or you invest in some city crampons, spikes you can attach to your everyday shoes.

End of the world fjord, near Sommarøy

After a night in Tromsø, the rest of the group from Zürich arrived and we headed off to Sommarøy on the coast. Amazing fjords entertained us for the full hour drive until we reached the open ocean. We took one final bridge to Sommarøy, which was on an island, seemingly at the end of the world, with nothing beyond besides the Arctic Ocean. Luca and Deva went back to Tromsø for the rest of the group (we didn’t fit in the car with all our luggage…) and Zhihong and I waited at the cabin. I relaxed on the beach outside, watching the beautiful dusk light play with the clouds.

As a gap in the clouds grew bigger and bigger, I was getting pretty excited. There had been a large solar flare a few days past and the solar activity was extremely high. Aurora sighting was looking inevitable. Sure enough, not long after dusk I saw a greenish grey smudge in the sky. It didn’t look like much, maybe a thin Cirrus cloud, maybe the Milky Way? After a few minutes convincing myself that it was actually the aurora, I ran inside to get Zhihong and texted Luca to hurry up and get back to the cabin. Zhihong and I watched as it got brighter and brighter, a faint colorless beam across the sky becoming a bright green beam. I remember being truly amazed and just staring off into the sky, but I honestly can’t remember much about this first sighting, because the best was yet to come.

When the rest of the group arrived, the aurora was again just a faint smudge, hardly worth looking at. The others looked a bit disappointed but we assured them that it gets better. Sure enough, an hour or two later it was bright again and we all went outside. I had given up on taking pictures for the night and just watched. It was a very bright, focused beam making an arc across the sky, until... The beam became unstable and started rippling, waves of intensity shot across the arc, faster than I would have ever imagined, and eventually the aurora started breaking apart into several wispy streams. What started as a bright focused beam, ended as a faint but extremely beautiful shape, spread across the sky. The aurora continued to break apart and become fainter and fainter over the next 20 minutes. The show was over for the night.

Sommarøy

Sommarøy is a photographer's paradise, it is exactly what you expect from a picturesque Norwegian fishing village. We had a relaxing day exploring around the area before getting another phenomenal night of aurora. This time we decided to drive a little ways to get away from the lights of the village. We started watching earlier in the aurora's development and could watch the beam get stronger and stronger until it was the brightest we had seen. Then, just like the previous night, it started to ripple, the waves growing larger and faster until the whole beam broke apart and magnificent green shapes spread to all corners of the sky. We watched for quite a while longer as these green shapes morphed into different forms like passing clouds, and gradually faded away. It got dimmer and we went back to the cabin.

Aurora mission complete!

The aurora left us with a lot of questions. Why is it green? What causes it to go unstable and shoot off streamers across the sky? Why is it happening at some points in a night but not others? I knew the basics: the aurora occurs when ions ejected from the sun (the solar wind) follow the magnetic field lines of the Earth into a region around the poles. As they get closer to the Earth, the Earth's magnetic field absorbs their energy as they begin to spin rapidly around magnetic field lines. In the process they impact gas molecules, losing the rest of their energy and giving off light. With a bit of research I found that the most common green color is an emission line from oxygen at a height of roughly 100 km. Red is from oxygen higher in the atmosphere. Nitrogen adds several other colors.

As for the instability and filamentation, from what I can tell, what we are seeing is a result of a plasma wave called an Alfvén wave which results from ions being pulled back towards magnetic field lines. This force makes the magnetic field line act like a rubber band on which waves can form. We may have also been seeing an instability due to two sheets of ions with different currents moving past each other, similar to the curls that can be seen in cloud when there is an interface between two winds with different speeds (Kelvin-Helmholtz instability). Some combination of these oscillations can become unstable and the beam breaks down turbulently into the spectacular shapes that we saw (Take everything I said here with a grain of salt, I'm not an expert but I did my best. Here's a rather old reference). Still lots of questions. Plasma physics is interesting stuff.

After a bit more daytime exploring around beautiful fjord Norway, the rest of the group was headed back to Switzerland. They took me to the edge of Tromsø and dropped me off so that I could head into the backcountry for two nights. I was headed into the Tromsø Fastland, some flat-topped mountains that look over Tromsø. The mountains were entirely covered in ice, just like the city. I put on my snowshoes just so I didn’t have to carry them and headed up into the mountains. After less than an hour I was on a ‘trail’ that hadn’t been tracked all winter. A flat ice covered landscape extended endlessly in all directions. For the entire day of hiking the sun was low on the horizon, glowing eerily through the clouds. I was constantly turning to take pictures of my line of footprints extending to the horizon on an otherwise barren landscape.

The Tromsø Fastland

I stayed at two different cabins, which were isolated in the middle of this barren landscape. They were incredible cozy with 4 beds each, a stove, and a wood-burning stove to keep warm. Both nights I was alone, though I met a few Norwegians on their way out of the first cabin. They were students from the University of Tromsø out for the weekend to study in the peace and quiet of the cabins, such an amazing thing to be able to do. 

Skarvassbu, the first cabin, lost in a sea of white

There was cloud cover the 1^st night and as such, no aurora. I couldn’t complain because the sunset was the best I had seen all year, maybe the best I’ve ever seen. It lasted for an hour with spectacular color reflecting from every ice-covered surface, that is, everything. I got a spectacular hike in the next day, a nearly cloudless day, giving me high hopes for the Aurora.

Hiking in the Tromsø Fastland

I arrived at Blåkollkoia with the last light of sunset fading from the landscape. It was down in a sparse forest, making the landscape a bit less picturesque but more cozy. I made a simple dinner and got the fire going. By the time I was done, it was dark and I went outside to check on the aurora. I was shocked as soon as I opened the door by an aurora display more spectacular than I could have imagined. I twisted shape glowed vividly above the horizon, reminiscent of a vast alien spacecraft. I geared up for the cold and went out for some photography. In addition to the spectacular green vortex in the East, there was an arch across the sky emerging from some mountains in the west. I ran around the cabin, getting different angles, alternating between the west and east sides of the display, it was too big to watch all at once, the whole sky was glowing. The display lasted for hours. During the brightest times the entire landscape was lit up green, the aurora reflecting off the snow. I was fascinated by how dynamic it was, constantly something new happening – a rippling instability, new beams developing, oscillating in brightness between one side of the sky and the other. I went back inside several times to warm up and could watch from the window. With a fire constantly burning in the tiny cabin it was sweltering inside, easily qualifying as a sauna. Ultimately, I went to sleep with the aurora still going strong, it probably continued the full night.

I went to sleep to aurora and woke up to magnificent sunrise light, there was never a dull moment. I spent the day getting back to Tromsø where I was to pick up a car for the last few days of my trip. I spent a night bumming on the side of the road, totally fine to do in Norway, then decided to try to make it all the way down to the Lofoten Islands where a friend of mine was staying for vacation. It was an epically long drive in completely awful weather and not without issue. I’ll skip the long story there. It was well rewarded by good company and the spectacular scenery of the Lofoten Islands, rugged mountains jutting out of the sea on all sides of what has to be the most scenic road in the world. The road was complete with an underwater tunnel, several tunnels through giant mountains, and many spectacular bridges. The stormy weather made the place even more breathtaking and intimidating. I only had a day there before I had to take the long journey back to Tromsø and back home.

Driving through the Lofoten Islands

 

Svolvaer, Lofoten

My last day the weather was so bad - freezing temperatures, fierce winds, sideways snow and sleet - that I went to the airport early and read a book. This trip was simply incredible and I am now completely obsessed with the far north. I want to go back any chance I get.