A couple of years ago, fed up with the daily grind and the men in our life (a frequent complaint, if I’m honest), my mum and I embarked on a girl’s trip. First, and anyone who has done this will know, came the trials and tribulations of choosing a destination. I am a bit of a space case, in that flying gives me the willies, and I will literally do anything to get out of it (truly, I once took a 9.5 hour bus journey at twice the cost to avoid a 1.5 hour flight), but thankfully, my mum loves nothing more than a cruise, so that was an easy issue to resolve. But where would we be chugging off to on the high seas? In the end we settled on Norway, because we had never been, and who would turn down the opportunity to see perhaps the most famous natural light show on earth? We are hot weather mortals, so we had to speed buy ski trousers and ear hats and those jackets that make you look like Michelin Man and look good on no-one, ever, because we were not just going to Norway, we were going 250 miles into the Artic Circle. In March. I have a condition called Raynauds, which essentially means that my blood vessels are tight arses and refuse to let blood pass to my hands and feet and in cold weather, I end up resembling those blue Avatar people, so I was beginning to question my own sanity. But press on we did, and soon, we were waving the men-folk off at Southampton port, and settling down with an obligatory holiday cocktail as we set sail. By happy accident, a couple of days into our trip was due to be the date of the total solar eclipse being visible from Torshavn, in the Faroes, so we diverted there for that occasion (see Why Astronomy? for details on that particular adventure).
Soon, we arrived in Norway, viewing the most incredible fjords and proper, powdery, fluffy snow, not that damp smelly mush we get in England. But the main event, was of course, the majestic Aurora Borealis. We docked at Alta, near the northern tip of Norway, and stayed for 2 nights to have the best chance of viewing them. We diligently studied the weather forecast, and plumped to journey out on the second night, which promised to be clearer. But it still was no guaranteed thing. On the first night, we watched as those who had tried their luck traipsed back to the ship, glum faces revealing misfortune. Soon, it was our turn, and we journeyed to a golf course in the middle of nowhere, far away from city lights, mountains rising ghost-like form the horizon, a lake frozen solid with thick ice glinting in the moonlight. It was -22 degrees celsius. I was bloody cold. To be fair, I had used my extra clothing, including socks, gloves, hats and even a jumper, to wrap my camera up to protect it from the frankly ridiculous temperatures. You know, priorities and all that. We stood, (literally) frozen to the spot, hoping furiously that those lights would appear in the sky, and sure enough, rippling over the mountains, they began to dance.
Now, if you’d indulge me, I would like to take a detour into science, by far one of my favourite detours to make, because I think that it makes the Aurora even more magical when you know why they dance for us. If some geek prattling on about physics and trying to convince you that it’s cool isn’t your idea of fun…well, you may be on the wrong blog, but feel free to skip the following paragraph.
Auroras occur at the magnetic poles of our planet, when solar wind emitted by the Sun, containing charged particles, enters the Earth’s upper atmosphere and collides with oxygen and nitrogen atoms approximately 200 miles above the surface. These collisions and the resulting reactions cause the aurora that we then see, and the constantly shifting combinations of these collisions cause the lights to “dance” across the sky. The different colours depend upon the type of atom that is struck, and the altitude at which the collision takes place. Observe below:
•Green – oxygen, up to 150 miles in altitude
•Red – oxygen, above 150 miles in altitude
•Blue – nitrogen, up to 60 miles in altitude
•Purple/violet – nitrogen, above 60 miles in altitude
Of course, our Sun is an extraordinarily powerful star, and the force of it’s solar winds are truly awe inspiring, and honesty slightly alarming. Just look at what it did to poor old Mercury. So the magnetic poles, and the busy little atoms contained within them, are actually shielding us from these harmful winds. The aurora is our planet visibly protecting us from the wrath of the Sun, in the most beautiful way imaginable. And I think, that makes it even more wonderful.