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[No picture] Pulsating Aurora over Iceland

Explanation: Why do some auroras pulsate? No one is sure. Although this unusual behavior has been known for a long time, the cause remains an active topic of research. Featured here is a dramatic video that captured some impressive pulsating auroras in mid-March over Svínafellsjökull Glacier in Iceland. The 48-second video is shown is not time-lapse. The real-time pulsations are exemplified by sequences where the astrophotographer is visible moving about in the foreground. A close inspection of the enigmatic flickering sky colors reveals that some structures appear to repeat, while others do not. The quick rapidity of the pulsations seen here is somewhat unusual -- more common are aurora with pulsations that last several seconds. Recent research shows that pulsations are more common in electron-generated aurora, rather than proton aurora, and that the Earth's local magnetic field may fluctuate in unison.

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This is called Astronomy Picture of the Day, not Video of the Day. I am outraged at the false advertising, the need to click slow-loading videos, and the abandonment of your principles in favor of the gaping slack-jawed yokels who must drool at a video all day long.

It's ok, Bob. There's always tomorrow.

Damn, I hate it when the slack-jawed yokels have faster internet than me. I'm a purist too, Dr Bob. I kept my eyes closed long enough for me to pause the video, just so that I could admire a still frame in the sanctimonious manner to which I am accustomed. Ahhhhh.

Whether or not you think APOD should feature videos from time to time, today's moving picture would have been much less compelling without the video. I have never seen a pulsating aurora before, even as a video. I wouldn't know what to make of the picture if it were a still photo and the description told of the photographer's experience and that the aurora was pulsating. There are many ways in which a thing could be described as pulsating and the quickest way to make it clear is with a video. So, thanks, Stéphane.

Looks like some of the stars are pulsating, too.

Ann

I don't think an Aurora is a pulsating phenomenon. Rather, it appears to be an optical illusion due to atmospheric activity in the upper atmosphere of the Earth. Or, the pulsating appearance may be the result of sunlight bouncing off the ionic fabric of the Aurora. Whatever the explanation, it is a topic which deserves research and plenty of funding. There is at least one other reason why an Aurora appears to pulsate. However, rather than spill my brains out for an issue without compensation I will let it go here sorry ..

Ann wrote:Looks like some of the stars are pulsating, too.

I noticed that. I think it might be a quirk with how the camera works, some kind of compression thing, and atmospheric twinkling on top of one or both of those.

Hello,
Thank you to appreciate. Sorry, Dr. Bob, but transcribe a phenomenon so dynamic, is impossible, other than with a video. For technical reasons, the filmed portions are quite narrow (full frame camera, 24mm lens, F1,4). To the naked eye, it seemed a flow of energy, extremely fast, that were flashing all the sky. Anyway, it was something very impressive. Another observation is that, blinking are red (the camera is modified to be more sensitive in the H-alpha radiation). Especially for Ann, "Pulsating Aurora" is an appetizer, I recommend the main course, "Litríkur Stormur" ( Color Storm in icelandic) :
Stephane Vetter

The video was great, and it ran smoothly even on my relatively old Mac. And seeing it took me back to my youth in Canada, seeing this kind of thing from time to time in the heavens above! Good work as usual, APOD!

Nuitsacrees wrote:Hello,
Thank you to appreciate. Sorry, Dr. Bob, but transcribe a phenomenon so dynamic, is impossible, other than with a video. For technical reasons, the filmed portions are quite narrow (full frame camera, 24mm lens, F1,4). To the naked eye, it seemed a flow of energy, extremely fast, that were flashing all the sky. Anyway, it was something very impressive. Another observation is that, blinking are red (the camera is modified to be more sensitive in the H-alpha radiation). Especially for Ann, "Pulsating Aurora" is an appetizer, I recommend the main course, "Litríkur Stormur" ( Color Storm in icelandic) :
Stephane Vetter

Beautiful video, Stephane! Particularly, for me, the amazing bluish aurora in the first part of it. But it is all very beautiful.

Ann

Does not matter how or why this effect is produced. Am sure the video is not out there to manipulate. Stand back and take in the awe.

geckzilla wrote:Whether or not you think APOD should feature videos from time to time, today's moving picture would have been much less compelling without the video. I have never seen a pulsating aurora before, even as a video. I wouldn't know what to make of the picture if it were a still photo and the description told of the photographer's experience and that the aurora was pulsating. There are many ways in which a thing could be described as pulsating and the quickest way to make it clear is with a video. So, thanks, Stéphane.

I don't have a problem with the occasional video. Unfortunately, my Internet quality means I can't really stream them, however. I wish that more were available for direct download. As it is, I have to use a third party capture tool to snag the video from Vimeo in order to properly view it from my computer. That's a lot of trouble... enough that I only do it with videos that really catch my interest. This one hasn't risen to that level, so I haven't yet seen it. I may or may not.

Chris Peterson wrote:

geckzilla wrote:Whether or not you think APOD should feature videos from time to time, today's moving picture would have been much less compelling without the video. I have never seen a pulsating aurora before, even as a video. I wouldn't know what to make of the picture if it were a still photo and the description told of the photographer's experience and that the aurora was pulsating. There are many ways in which a thing could be described as pulsating and the quickest way to make it clear is with a video. So, thanks, Stéphane.

I don't have a problem with the occasional video. Unfortunately, my Internet quality means I can't really stream them, however. I wish that more were available for direct download. As it is, I have to use a third party capture tool to snag the video from Vimeo in order to properly view it from my computer. That's a lot of trouble... enough that I only do it with videos that really catch my interest. This one hasn't risen to that level, so I haven't yet seen it. I may or may not.

You can directly download this video from Vimeo : https://vimeo.com/128714112 , tab "download"
Stephane

Nuitsacrees wrote:

Chris Peterson wrote:I don't have a problem with the occasional video. Unfortunately, my Internet quality means I can't really stream them, however. I wish that more were available for direct download. As it is, I have to use a third party capture tool to snag the video from Vimeo in order to properly view it from my computer. That's a lot of trouble... enough that I only do it with videos that really catch my interest. This one hasn't risen to that level, so I haven't yet seen it. I may or may not.

You can directly download this video from Vimeo : https://vimeo.com/128714112 , tab "download"
Stephane

Thanks! Never noticed that option before.

The stars looked OK to me, remember that the light of the aurora is added to the light of the stars, no blocking of the background light occurs. The stars would then, sort of, pulsate a little themselves as the intensity of the light varied. If you look 2/3 of the way across from the left and about 1/4 of the way from the top, there is a planet or something moving against the stars toward the bottom.

...between time 0:04 and 0:12 at the beginning.

I'm guessing that most people who upload their videos do not enable the download option.

I can't imagine what early hominids thought of auroras. Maybe it's the sound on the video but the shapes they create almost seem angelic pulsating as they move across the sky.
Edit - Here are a few examples from a quick search.

http://www.polarbearsinternational.org/ ... pretations

http://www.amscan.org/pdf/Fall08AuroraBorealis.pdf

http://www.vikinganswerlady.com/njordrljos.shtml

geckzilla wrote:I'm guessing that most people who upload their videos do not enable the download option.

Probably not. But it's nice for those of us with slow Internet. And you can download any of the videos using third party tools, so there's little protective value in disabling that option.

I, too, don't mind the occasional, infrequent video. In this particular case, I don't see how a still picture could have conveyed to essence of this phenomenon. And for me, the most interesting aspect of today's entry is knowing that these images were not shown in time-lapse. I don't know what the photographer's intentions where when she walked in front of camera, but doing so very effectively demonstrates that the pulsations are depicted in real time—and if that was the sole intent, then kudos for thinking of it.

Nuitsacrees wrote:I recommend the main course, "Litríkur Stormur" ( Color Storm in icelandic)

The segment starting at 4:50--Incredible! Magnificent! Merci beaucoup!

Thank you Stephane Vetter, that was very nice video and the "Litríkur Stormur" was fantastic!

rwlott wrote:I, too, don't mind the occasional, infrequent video. In this particular case, I don't see how a still picture could have conveyed to essence of this phenomenon. And for me, the most interesting aspect of today's entry is knowing that these images were not shown in time-lapse. I don't know what the photographer's intentions where when she walked in front of camera, but doing so very effectively demonstrates that the pulsations are depicted in real time—and if that was the sole intent, then kudos for thinking of it.

My view exactly.
Here at my house, I was treated to an amazing pulsating aurora in 2004. Unlike the today's AVOD, the one I witnessed was incredibly symmetric. Not only did I see a very large auroral corona directly overhead (at first I thought the sky was clouded out LOL!), there were concentric annular rings, maybe 5°to 10°thick, starting from the convergence point and propagating outward to edges of the corona where the rings would disappear. Only one ring at a time would form but they each would traverse the display in a fraction of a second, and they appeared at the rate a couple or few times a second. I felt like I was in a huge, old sci-fi tractor beam! I've never seen (nor hear of) anything like it before or since, and today is the first I've seen pulsating auroras mentioned let alone a video. Every time I think about this experience I wish I had a video of it. My words really don't do it justice.

rwlott wrote:I, too, don't mind the occasional, infrequent video. In this particular case, I don't see how a still picture could have conveyed to essence of this phenomenon. And for me, the most interesting aspect of today's entry is knowing that these images were not shown in time-lapse. I don't know what the photographer's intentions where when she walked in front of camera, but doing so very effectively demonstrates that the pulsations are depicted in real time—and if that was the sole intent, then kudos for thinking of it.

I'm having trouble readily finding information about Stéphane but had thought that name is Stephen and so the photographer was male. Unless you knew about Stéphane you have better eyesight than me rwlott to indentify Stéphane as female from the video!