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Behavior of Aurora Australis Around A Dark Spot on Composite Image

  1. Jun 18, 2009 #1
    On http://en.wikipedia.org/wiki/Aurora_(astronomy [Broken]), about 1/2-way down the page, there is an image of, quote, "Aurora australis (September 11, 2005) as captured by NASA's IMAGE satellite, digitally overlaid onto the The Blue Marble composite image." Next to it, there is a rolling video of, quote, "An animation created using the satellite data."

    My questions are, “Why does the light of the aurora seem to be attracted, or connected, to the area near that spot?”, and “what is the spot?”.

    [edit by Ivan: inappropriate references deleted]


    My own determination is that the video on Wikipedia shows the light of the aurora seeming to come down next to the dark spot to the ground near the dark spot’s right, especially towards the last part of the video. Maybe it’s just the way I’m looking at it. It’s hard to tell what the depth of the aurora is. The Hollow Earthers are showing only a fragment of the video to deceive people into thinking the light of the aurora is coming up from the dark spot. I don’t know what the dark spot is, but it looks to me like part of the sea surrounded by a sheet of ice connected to the continent. I might be wrong. I don’t know the geography. The image in the photo is a composite image, so it may be different from a regular photo.

    Again, why does the light of the aurora seem to be attracted to the area near the spot, and what is the spot?
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jun 26, 2009 #2
    Kingarthur,

    First of all, that's a stunning image and animation...thank you for sharing.

    Secondly, good question. It does indeed appear that the aurora is somehow focused around this point. Note that the image of the planet surface is clearly stated to come from the Blue Marble composite satellite image, which the aurora information was overlaid onto...so this is not a true image we are seeing, and they were not even taken at the same year.

    After downloading the high resolution Blue Marable imagery (note that my version is from the same series but is not the exact same image) that was used to construct this rendition, I was able to locate the black spot you are referring to. It turns out to be the exact south pole. In other words, the straight line along the bottom of the digital map is condensed into this point. The reason it appears black is simply due to a rendering artifact due to this point being condensed...ie, there's not really a black spot there in real life.

    You can see that here in this rendering I made

    http://img200.imageshack.us/img200/1021/polet.jpg [Broken]

    The aurora is caused by effects of the Earth's magnetic field, so it is not surprising that it should be concentrated about the exact location of the magnetic south pole like this.
     
    Last edited by a moderator: May 4, 2017
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