A tale of a frozen family

The Aurora Borealis are natural colored light displays, which are usually observed in the night sky, particularly in the polar zone. Some scientists call them “polar auroras” (or “aurorae polares”). In northern latitudes, it is known as the aurora borealis, named after the Roman goddess of dawn, Aurora, and the Greek name for north wind, Boreas. It often appears as a greenish glow (or sometimes a faint red), as if the sun were rising from an unusual direction. The aurora borealis is also called the northern polar lights, as it is only visible in the North sky from the Northern Hemisphere. The aurora borealis most often occurs from September to October and from March to April.

Auroras are produced by the collision of charged particles from Earth’s magnetosphere, mostly electrons but also protons and heavier particles, with atoms and molecules of Earth’s upper atmosphere (at altitudes above 80 km). The particles have energies of 1 to 100 keV. Most originate from the Sun and arrive at the vicinity of Earth in the relatively low-energy solar wind. When the trapped magnetic field of the solar wind is favourably oriented (principally southwards) it reconnects with Earth’s magnetic field, and solar particles enter the magnetosphere and are swept to the magnetotail. Further magnetic reconnection accelerates the particles towards Earth.

The collisions in the atmosphere electronically excite atoms and molecules in the upper atmosphere. The excitation energy can be lost by light emission or collisions. Most aurorae are green and red emission from atomic oxygen. Molecular nitrogen and nitrogen ions produce some low level red and very high blue/violet aurorae.

Typically the aurora appears either as a diffuse glow or as “curtains” that approximately extend in the east-west direction. At some times, they form “quiet arcs”; at others (”active aurora”), they evolve and change constantly. Each curtain consists of many parallel rays, each lined up with the local direction of the magnetic field lines, suggesting that aurora is shaped by Earth’s magnetic field. Indeed, satellites show electrons to be guided by magnetic field lines, spiraling around them while moving towards Earth.

The curtains often show folds called “striations”, which are curtain-like. When the field line guiding a bright auroral patch leads to a point directly above the observer, the aurora may appear as a “corona” of diverging rays, an effect of perspective.

Although it was first mentioned by Ancient Greek explorer/geographer Pytheas, Hiorter and Celsius first described in 1741 evidence for magnetic control, namely, large magnetic fluctuations occurred whenever the aurora was observed overhead. This indicates (it was later realized) that large electric currents were associated with the aurora, flowing in the region where auroral light originated. Kristian Birkeland (1908)[1] deduced that the currents flowed in the east-west directions along the auroral arc, and such currents, flowing from the dayside towards (approximately) midnight were later named “auroral electrojets” (see also Birkeland currents).

Still more evidence for a magnetic connection are the statistics of auroral observations. Elias Loomis (1860) and later in more detail Hermann Fritz (1881)[2] established that the aurora appeared mainly in the “auroral zone”, a ring-shaped region with a radius of approximately 2500 km around Earth’s magnetic pole, not its geographic pole. It was hardly ever seen near that pole itself. The instantaneous distribution of auroras (”auroral oval”, Yasha/Jakob Feldstein 1963[3]) is slightly different, centered about 3-5 degrees nightward of the magnetic pole, so that auroral arcs reach furthest towards the equator around midnight. The aurora can be seen best at this time.

WHEW! So…. there is the science behind the Aurora Borealis. (Thank you google!) I’ve also included a bunch of pictures that I found on Google, of the Aurora . Photographing the northern lights is a difficult task at best. You’ve got to be a pretty accomplished photographer and have your cameras set right if you ever hope to get a decent picture. I can’t tell you how many rolls of film hubby and I went through before we realized we just weren’t cut out for it. There is a gentleman here who gives a good lesson on what it takes to capture some pictures. We tried them… we failed That is why I love google so!

Here is a picture taken from outerspace (compliments of NASA). Is this not amazing?

At any rate. The human perspective of the Aurora is this….. it’s beautiful. It’s breath taking. It’s something that you can’t experience the feeling of, with anything else. I remember when we lived in Fairbanks (who gets the lights a lot more than where we are now) laying in the back of my pick up and just watching them for as long as I could physically stand the cold. I swear that you can hear them. All of that was topped by the time I flew THROUGH them…. AMAZING! ABSOLUTELY AMAZING. It was a TON of turbulence, but utterly AMAZING.

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