Sunday, February 6, 2011

Curtains of Light

Feb 5, 2011 11:44:10 PM

Since we came up here we've seen several aurora displays. Most of the time it looks like fog or mist or some weird faint clouds that move in decidedly un-cloudlike ways. Once in awhile, like last night, you get some truly crazy light shows. Last year I tried taking movies but they came out black. This year I got smart and took still pictures.

What causes this strange and beautiful phenomenon? The sun emits streams of electrons that are drawn towards the earth's magnetic poles. Way up above us in upper reaches of our atmosphere, about 50 miles high, they react with gas molecules (mostly nitrogen and oxygen). The electrons hit the gas molecules like billiard balls, and the "balls" emit light upon being struck. There has to be some insanely high concentration of these particles to be able to see the light emitted in these reactions (several million charged particles per square centimeter or something like that).

Because this solar wind is drawn to both the North and South magnetic poles, the display we saw last night dancing over Fairbanks would have been seen in mirror-image by scientists stationed in the South Pole!!!

The first time you see an aurora you might be kind of disappointed in the lack of psychedelic colors--that is because photographs capture colors we don't really experience. I tried to show what the actual hues are compared to what the camera sees.

Kinetically, the aurora moves and flows like slow motion lightning--it just rolls, swirls, pulsates, gyrates. You must come up and see it for yourself!



11:52:53 PM, original color from camera is very green

11:52:53 PM, what we see with the naked eye


12:00:31 AM