APOD: Aurora Over Norway (2010 Sep 20)

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APOD: Aurora Over Norway (2010 Sep 20)

Postby APOD Robot » Mon Sep 20, 2010 3:59 am

Image Aurora Over Norway

Explanation: Auroras can make spectacular sights. Photographed above last weekend, flowing multi-colored auroras helped illuminate a busy sky above Tromsø, Norway. Besides the spectacular aurora pictured above, the photographer caught three satellites streaks, one airplane streak, and a friend trying to capture the same sight. Although auroras might first appear to be moonlit clouds, they only add light to the sky and do not block background stars from view. Called northern lights in the northern hemisphere, auroras are caused by collisions between charged particles from the magnetosphere and air molecules high in the Earth's atmosphere. If viewed from space, auroras can be seen to glow in X-ray and ultraviolet light as well. Predictable auroras might occur a few days after a powerful magnetic event has been seen on the Sun.

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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby Benbrilling » Mon Sep 20, 2010 5:11 am

I have only seen auroras in photographs. Can someone who has actually seen them tell me if they look the same in real life? They are apparently always photographed with long exposures (as is obvious in this case because of satellite and airplane streaks). I am just curious about whether photographs give an accurate representation of the actual experience. (And trying to decide if it is worth it to gamble the cost of a trip north on the chance of catching an aurora display.)
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby orin stepanek » Mon Sep 20, 2010 12:57 pm

Click to play embedded YouTube video.
8-)
They are awesome!
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby rstevenson » Mon Sep 20, 2010 1:10 pm

I believe the long exposure serves two purposes: it captures more of the moving sheets of light than a fast exposure would; and it makes it all somewhat brighter than it would otherwise be.

I've seen bright and vivid Northern Lights three times and they are indeed a spectacular and moving sight. But they can also be subtle -- I've seen traces of them, barely visible, many times. No matter their brightness, the most startling aspect of them is that they move! At times they seem to snap and whip across the sky, while at other times they hang in gently rippling curtains. But they're never still, as the video Orin just posted shows so well.

As for colour (though it's notoriously hard to accurately remember colour) it seems to me that that photo does show all the possible colours. It's very reminiscent of my best aurorae experience, which occured in northern Manitoba in the early 70s. It's the only time I've been under the seeming centre of the phenomena. I developed a serious crick in the neck before I finally gave in to the cold and went back inside.

Rob
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby unclepedro » Mon Sep 20, 2010 4:18 pm

I think there may be at least two more traces in the aurora picture from today. Directly right from the center (short) trace, and outside of the aurora field, there is what appears to be a faint trace running from about 1 to 7 o'clock. Then, above and to the left of the lowest trace, there is a very dim, short trace(?) from about 2 to 8 o'clock. I assume those must be satellites as well?
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby Benbrilling » Mon Sep 20, 2010 4:47 pm

Thanks for the replies!

Even the videos are obviously long exposures per frame. I am still wondering how accurately they depict actual auroras. While long exposure videos show beautiful images of a waterfall or surf, they don't really look the same as real time video. So my followup question would be: do videos give one a real representation of what an actual aurora looks like?

I've always wanted to see one, but if a video is pretty accurate, maybe I don't really need to spend a lot of money to go all the way to Alaska and wait around for days in freezing temperatures in hopes of seeing one. Is the real-life experience really worth the money and cold nose? (Not to mention the risk of none occurring before my plane or boat is scheduled to take me home?)

Thanks!
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby emc » Mon Sep 20, 2010 5:51 pm

amazing image of amazing phenomenon… has an “other-worldly” look to it… especially in Orin’s video… a surreal nature show… but not “strange” thanks to our earthly science majors
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby bystander » Mon Sep 20, 2010 7:05 pm

Benbrilling wrote:I've always wanted to see one, but if a video is pretty accurate, maybe I don't really need to spend a lot of money to go all the way to Alaska and wait around for days in freezing temperatures in hopes of seeing one. Is the real-life experience really worth the money and cold nose? (Not to mention the risk of none occurring before my plane or boat is scheduled to take me home?)

Northern Lights Get Internet Reality Show
Space.com | NightSky | 20 Sept 2010
Aching to see the dazzling aurora displays that make up the northern lights, but can't get to the Arctic Circle to see them? Don't worry, a new Internet show has you covered.

The new web-based observatory AuroraMAX will go live tonight (Sept. 20) to broadcast real-time views of eye-catching northern lights, called the aurora borealis, as part of an outreach project by the Canadian Space Agency. ...
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby DonAVP » Mon Sep 20, 2010 7:07 pm

I really like the dynamics of the image. Look at the shooting stars. They look like they are be flung by force from the center of what ever is causing the Aurora. Very beautiful !!! Be sure and second click to load the image in it own window then you can zoom into 1/1 and see much more detail.

Someone could say this is a night launch from the Cape and i would have had a hare time explaining that it was not.

Don
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby hstarbuck » Tue Sep 21, 2010 1:29 am

Very cool how the densest portions are the brightest. Here's an aside: What other objects/bodies/phenomenon in astronomy are considered self-luminous in visible light besides stars? Do planetary nebulae count as they luminesce due to uv from inner star? I may have worded this funny, but what I am getting at is this: what objects emit visible light due to intrinsic properties or processes and not just reflect or refract it. For instance, hot lava would (at night especially) and the moon would not, lightning would and a raindrop would not.
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Re: APOD: Aurora Over Norway (2010 Sep 20)

Postby mpharo » Sat Sep 25, 2010 12:12 am

The showing of the Aurora Borealis over Norway in green is a very beautiful display. It starts out as blue on top, then further down it starts turning teal (mixed in with some pink), then dark green on the bottom. I never would have guessed that you would be able to see the stars through the veil. The aurora is sort of like a giant firework show, only bigger.
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