APOD: Aurora Over Iceland (2012 Mar 21)

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APOD: Aurora Over Iceland (2012 Mar 21)

Post by APOD Robot » Wed Mar 21, 2012 4:06 am

Image Aurora Over Iceland

Explanation: If you see a sky like this -- photograph it. Three nights ago in Iceland, an adventurous photographer (pictured) chanced across a sky full of aurora and did just that. Afterwards, by stitching together five smaller photographs, the entire aurora-lit sky was recreated in this 180-degree panorama taken from Vatnaj�kull glacier. Auroras are sparked by energetic particles from the Sun impacting the magnetic environment around the Earth. Resultant energetic particles such as electrons and protons rain down near the Earth's poles and impact the air. The impacted air molecules obtain excited electrons, and when electrons in oxygen molecules fall back to their ground state, they emit green light. Auroras are known to have many shapes and colors.

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by Beyond » Wed Mar 21, 2012 4:12 am

Brrr, t-t-that's a n-n-ice p-p-picture!-!-! S-o-m-ewhere over the greenbow, way up high. There's a lot of angry particules, ir-ritating the sky.
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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by starstruck » Wed Mar 21, 2012 5:18 am

I keep looking every night, but I've still not been lucky enough to see any sign of the Northern Lights from here. I'll keep looking and hoping though. Certain that if I did, I know I wouldn't be able to get as good a picture as this! It is beautiful!

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by Sandstone » Wed Mar 21, 2012 5:57 am

But just think, somewhere up in the arctic circle there's some poor fellow with his 20" scope, eager for some deep-sky work, who looks out his remote cabin window and says "drat! another night of viewing ruined by these blasted auroras!" :)

But more seriously... Is one reason we love auroras so much due to their inaccessibility for many of us? I've never seen one. If they were common and accessible, how would our attitude change? As astronomers, a lot of what we look for are things that are, for one reason or another, hard to see. How about changing to botany or geology and not having to worry about expensive optics or sky conditions? :wink: Okay, no, it wouldn't be the same. (written while I'm listening to it rain outside, and forecast for next week is rain, rain, rain, rain...)

Nice picture, by the way.

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by Boomer12k » Wed Mar 21, 2012 6:35 am

Looks like Alien Doomsday....That is coool...

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by Stephen McDonald OKC » Wed Mar 21, 2012 11:05 am

Such beauty. Did you notice the twin violet beams that coincide with the twin peaks in the center? Coincidence? I think so. :ssmile: The beams are actually more than likely far behind and above those peaks.

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by orin stepanek » Wed Mar 21, 2012 12:39 pm

Another beautiful Aurora! Sometimes you can see them here in Nebraska! I haven't looked lately but right now it is quite rainy! :cry:
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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by neufer » Wed Mar 21, 2012 4:13 pm

http://asterisk.apod.com/viewtopic.php?f=30&t=27697&p=171452#p171368 wrote:
Chris Peterson wrote:
"I've never seen glare from snow as green, or heard it reported that way."
Art Neuendorffer

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by geckzilla » Wed Mar 21, 2012 7:13 pm

But wait! That's not glare.
Just call me "geck" because "zilla" is like a last name.

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by neufer » Wed Mar 21, 2012 8:18 pm

geckzilla wrote:
But wait! That's not glare.
Glare, n. [OE. glaren, gloren; cf. AS. glær amber, LG. glaren to glow or burn like coals, D. gloren to glimmer.]

1. A bright, dazzling light; splendor that dazzles the eyes; a confusing and bewildering light.

2. A fierce, piercing look or stare.
  • MACBETH: Avaunt! and quit my sight! let the earth hide thee!
    • Thy bones are marrowless, thy blood is cold;
      Thou hast no speculation in those eyes
      Which thou dost glare with!
3. A viscous, transparent substance.

4. A smooth, bright, glassy surface; as, a glare of ice. [U. S. ]
Art Neuendorffer

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by geckzilla » Wed Mar 21, 2012 8:32 pm

It is smooth. But it's not bright, dazzling, confusing, bewildering, or glassy.
Just call me "geck" because "zilla" is like a last name.

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by ta152h0 » Wed Mar 21, 2012 9:09 pm

just imagine our ancient ancestors living in Iceland watching one of these .......
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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by Cindy444 » Wed Mar 21, 2012 9:20 pm

Beautiful picture. I wish we could see aurora of any type from where I live. Problem is that is cloudy or rainding any night that there is a possibility of this. When it clears up the solar storms are long gone.

I have a question on your explanation which says oxygen molucules obtain excited electons from incoming solar radiation. I thought that the O (two in subscript) atoms in the atmosphere are all in a normal unexcited state. Hence they do not radiate. I do understand that the green light is emitted when excited electrons fall back to ground state in an oxygen atom. If an other electron is captured by one of these molucules, the atom will have too many electrons even if one of them is in an excited state. I do not see how the new captured electron can fall back to the ground state. It would seem that it would just be expelled or give the atom a negative charge. A more likely explanation would be that the solar radiation EXCITES an electron ALREADY in the oxygen atoms NOT that it causes the atom to capture an extra electron. (Note my model for this is pre quantum mechanics which I never have been able to completely understand so that may be why I am confused.) I would welcome anyone explaining the above to me.

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No Norse sagas mention aurora at all!?

Post by neufer » Wed Mar 21, 2012 9:50 pm

ta152h0 wrote:
just imagine our ancient ancestors living in Iceland watching one of these .......
http://www.vikinganswerlady.com/njordrljos.shtml wrote:
The Aurora Borealis and the Vikings

<<The Old Norse word for the aurora borealis is norðrljós, "northern lights". The first occurrence of the term norðrljós is in the book Konungs Skuggsjá (The King's Mirror, known in Latin as Speculum Regalae), written in 1250 AD, after the end of the Viking Age (the Viking Age dates ca. 800-1100AD), describing the Northern Lights as seen by settlers in Greenland:
  • "But as to that matter which you have often inquired about, what those lights can be which the Greenlanders call the northern lights, I have no clear knowledge. I have often met men who have spent a long time in Greenland, but they do not seem to know definitely what those lights are. However, it is true of that subject as of many others of which we have no sure knowledge, that thoughtful men will form opinions and conjectures about it and will make such guesses as seem reasonable and likely to be true. But these northern lights have this peculiar nature, that the darker the night is, the brighter they seem; and they always appear at night but never by day, most frequently in the densest darkness and rarely by moonlight. In appearance they resemble a vast flame of fire viewed from a great distance. It also looks as if sharp points were shot from this flame up into the sky; these are of uneven height and in constant motion, now one, now another darting highest; and the light appears to blaze like a living flame. While these rays are at their highest and brightest, they give forth so much light that people out of doors can easily find their way about and can even go hunting, if need be. Where people sit in houses that have windows, it is so light inside that all within the room can see each other's faces. The light is very changeable. Sometimes it appears to grow dim, as if a black smoke or a dark fog were blown up among the rays; and then it looks very much as if the light were overcome by this smoke and about to be quenched. But as soon as the smoke begins to grow thinner, the light begins to brighten again; and it happens at times that people think they see large sparks shooting out of it as from glowing iron which has just been taken from the forge. But as night declines and day approaches, the light begins to fade; and when daylight appears, it seems to vanish entirely.

    The men who have thought about and discussed these lights have guessed at three sources, one of which, it seems, ought to be the true one. Some hold that fire circles about the ocean and all the bodies of water that stream about on the outer sides of the globe; and since Greenland lies on the outermost edge of the earth to the north, they think it possible that these lights shine forth from the fires that encircle the outer ocean. Others have suggested that during the hours of night, when the sun's course is beneath the earth, an occasional gleam of its light may shoot up into the sky; for they insist that Greenland lies so far out on the earth's edge that the curved surface which shuts out the sunlight must be less prominent there. But there are still others who believe (and it seems to me not unlikely) that the frost and the glaciers have become so powerful there that they are able to radiate forth these flames. I know nothing further that has been conjectured on this subject, only these three theories that I have presented; as to their correctness I do not decide, though the last mentioned looks quite plausible to me."
There appears to be no substantiation for a connection between the god Ullr and the aurorae. People seem to have made a leap from the etymology of the god's name, which is connected with roots meaning "glory, shining", to the idea of the Northern Lights.

Similarly, there is the claim in Bullfinch's Mythology that the armor of the Valkyries "sheds a strange flickering light, which flashes up over the northern skies" making the aurora. Once again, there is nothing mentioned in the Old Norse literature that substatiates this assertion, and it can only be taken as either a fanciful interpretation, or perhaps an accretion from later folklore that arose after the end of the Viking Age.

A third misunderstanding about the Vikings and the Northern Lights is that the colorful auroral archways were identified as the Bifröst Bridge, which was a trembling and fiery path that fallen warriors could travel to Valhalla. In Gylfaginning ch. 13, a part of Snorri Sturluson's Prose Edda, we are clearly told that this bridge is in fact the rainbow:
  • "Er þér eigi sagt það að guðin gerðu brú til himins af jörðu, og heitir Bifröst? Hana muntu séð hafa. Kann vera að það kallir þú regnboga. Hún er með þrem litum og mjög sterk og ger með list og kunnáttu meiri en aðrir smíðir."

    "Have you never been told that the gods built a bridge from earth to heaven called Bifröst? (Quivering Roadway) You will have seen it, (but) maybe you call it the rainbow. It has three colors and is very strong, and made with more skill and cunning than other structures."
Strange as it may seem, when examining Old Norse literature, none of the mythological materials nor sagas mention the aurora at all.>>
Art Neuendorffer

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Re: APOD: Aurora Over Iceland (2012 Mar 21)

Post by slyman » Sat Mar 24, 2012 5:06 pm

pareidolia alert
there's a nice face with reddish eyes on the right side :)