The World Beyond BetterMost > Anything Goes
Beautiful Labrador NORTHERN LIGHTS
Front-Ranger:
Thanks, Mandy, those are heavenly!!!!! Just point me north!!!! I hear that in Alberta, you can sign up for a Northern Lights evening, where you are sledded up to an igloo by dogs and First Nations dancers perform for you, you can recline on furs, and watch the Northern Lights. It's one of my fondest dreams to do that one day!!!
Ellemeno:
I have seen much less vivid Northern Lights as far south as Missouri! I can't imagine what it would be like to see them really looking like that.
dela, what causes them?
SFEnnisSF:
Just awesome! :o
dmmb_Mandy:
I didn't take those pics but I did take these, up to my cabin, and for those who inquired about skidoos, those are my family's skidoos in the second pic:
Perhaps I'll win Jake over with the gorgeous Northern Lights up at my cabin? :-\ Though that's probably not the best foundation of a relationship! ;)
delalluvia:
--- Quote from: Ellemeno on June 09, 2006, 02:41:39 am ---dela, what causes them?
--- End quote ---
From NOAA, they say it better than me.
What Causes the Aurora?
The energy source for the aurora is 149 million km (93 million miles) from Earth at the sun. The sun continuously emits charged particles (mostly protons and electrons), which are the byproducts of thermonuclear reactions occurring inside the sun. These charged particles make up the solar wind, which travels away from the sun through space at speeds ranging from 300 to 1,000 km/sec.—about a million miles per hour. Traveling at this high speed, the solar particles can reach the Earth in two to three days.
At Earth, the steady solar wind is deflected by Earth's magnetic field, or magnetosphere. The solar wind flows around the magnetosphere much like a river flows around a stone. It also pushes on the magnetosphere and distorts it so that instead of a symmetric set of magnetic field lines—like one might have around a bar magnet—the magnetosphere is stretched and elongated into a comet shape with a long tail trailing away from Earth on the side away from the sun.
When there is a disturbance on the sun, such as a solar flare or coronal mass ejection, it can produce a disturbance in the solar wind. This in turn will cause a disturbance in the balance between the solar wind and Earth's magnetic field. As a result, electrons and protons are accelerated within the magnetosphere. These charged particles are constrained to the magnetic field lines much like beads on a wire. The accelerated particles will travel down the magnetic field lines of Earth and collide with the atoms and molecules of the upper atmosphere where the magnetic field lines reach down to surface of the Earth near the north and south magnetic poles.
When the particles from the magnetosphere collide with the atoms and molecules of the atmosphere, the particle's energy can be transferred to the atoms and molecules (typically O, N, and N2) of the atmosphere forming excited states of O, N and N2. When these finally release their energy and return to their normal ground state, they give up energy in the form of light. This is the light that we see from the ground as an aurora.
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