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Astro-Image of the Day: Aurora Borealis

This image shows a broad swath of aurora over the northern United States.

Click the image to see the story.

Scientists have discovered that some of the aurorae are polarized. This discovery will help scientists better understand Earth's upper atmosphere and magnetic field, and will help them study the Sun wind.




( 7 comments — Leave a comment )
Apr. 28th, 2008 04:46 pm (UTC)
Polarized? What does that entail? At the moment my understanding remains in the realm of excited electrons in atmospheric atoms. Certain elements "glow" appropriate colors when the electrons get excited.

Does that mean part of the aurora is positive and part of it negative?
Apr. 28th, 2008 05:16 pm (UTC)
If an electromagnetic wave is "polarized," its electric field points in one direction. Make sense?
Apr. 28th, 2008 06:07 pm (UTC)
More or less. Electro-magnetism wasn't one of my strong suits in physics. I am trying to put together a picture in my head of the field lines around the Earth. I need pretty labelled diagrams to make sense of this stuff.

To me it would seem self-evident that they would be polarized since the Earth's owns magnetic field is. Though I guess they assume since the solar wind isn't polarized it wouldn't be? But now they are finding out that it IS polarized... Is it polarized in the same directions as the Earth's field?
Apr. 28th, 2008 06:28 pm (UTC)
When I was at UIowa, my work-study job was taking solar wind data from the early 1970s that was captured on 8mm rolls and running it through a machine that was basically a giant contrived 35mm camera. We loaded the machine with 35mm film, put the 8mm in another way, and turned the thing on. It looked a lot like one of the engineering sets from Star Trek: TOS.

Right at the end of my gig, we started looking at a new-fangled technology that could store more data: the computer CD.
Apr. 28th, 2008 06:30 pm (UTC)
May. 7th, 2008 10:21 am (UTC)
That's really cool. The only thing that would make it cooler would be if it had been taken with a color camera.
May. 7th, 2008 04:36 pm (UTC)
Absolutely. I suspect it has something to do with the polarization camera.
( 7 comments — Leave a comment )