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Thursday, May 30, 2013

An Amazing Look at the Northern Lights!



“I came from the country, and when I came to the city, I was ridin’ high, you know. I was seeing more lights than I ever dreamed to shine in the world. ‘Cos where I came from, there wasn’t too many lights. Bugs made a lot of light, but after that there wasn’t no lights.” -John Hunter
John Hunter should have been at a higher latitude! Because if you’re fortunate, at a high enough latitude (either north or south), the following sight will sometimes greet you in the night sky.

Image credit: Thundafunda.com.
In the northern hemisphere, we call it the Aurora Borealis, while the southern gets the Aurora Australis. From the Earth, it looks like great multicolored ribbons slowly moving across the sky, while from space, you can clearly see that something interesting is going on in Earth’s atmosphere.

Image credit: International Space Station.
From this angle, it’s pretty clear that something’s going on from above. In other words, something’s coming in from space to strike the Earth’s atmosphere, producing this great display of lights.
Can we zoom out even more, you ask?

Image credit: NASA's IMAGE satellite.
Of course we can! The Aurora Australis, as photographed here by NASA, can make a spectacular “ring” pattern as seen from above. The Aurorae aren’t unique to Earth, either. We’ve seen them on many other planets, including Saturn (below).

Image credit: Hubble Space Telescope.
So where do they come from? Believe it or not, the Sun! The incredible temperatures and energies of the Sun not only ionize matter, but send these charged particles hurtling through space towards us at thousands of kilometers per second!
How will we ever survive?!

Image credit: NASA.
Well, thankfully, here on Earth we’ve got a great magnetic field! And one of the wonderful things about magnetic fields is that they bend charged particles, which means that — for the most part — our own planet deflects this radiation from the Sun safely away from Earth!
Except, that is, near the North and South magnetic poles, where those field lines all appear to enter/exit our planet. And whenever the Sun emits a flare, prominence, or other “event,” here’s what happens.

Image credit: NASA's Marshall Space Flight Center.
The North and South magnetic poles act as funnels, pulling charged particles into the upper atmosphere in a ring around the magnetic poles! These particles come in, and are energetic enough that they knock electrons off of their atoms in the atmosphere!

Image credit: International Atomic Energy Association.
Those electrons then recombine with atoms, producing the spectacular light show in that beautiful ring-like pattern we saw above. And at high enough latitudes, parts of that “ring” become visible to human eyes, and that’s what you see as the aurorae!
Last week, there was a spectacular show, and it was captured at high northern latitudes by many amateur and professional photographers.

Image credit: Will Gater, who has more images of Aurora hunting in Finland at willgater.com.
But, by far, the most amazing look comes from Terje Sorgjerd, who has created the best astrophotography video I’ve seen all year. Have a look, and make sure you’re sitting down.

(Thanks to Nancy Atkinson for this amazing find!)
We normally think of aurorae as these static ribbons in the sky, but taking a look at a time-lapse of them, you can see that nothing could be further from the truth! I hope you enjoyed this stunning look at the most beautiful natural light show the world has to offer

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