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Aurora colors in a bottle

  1. Jun 9, 2017 #1
    Last edited: Jun 9, 2017
  2. jcsd
  3. Jun 9, 2017 #2

    davenn

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    what makes you say that ? it clearly stated who took the photo and where it was taken

    the changing colours ... in the real aurora foto or in that experiment ?

    In a real aurora, it is mainly the oxygen and nitrogen atoms getting ionised and creating their specific colours, mostly red and green
    those colours then mix to produce other colours that are seen ... purples, yellow, sometimes blues


    Dave
     
  4. Jun 10, 2017 #3
    Im trying to figure this out. I know that aurora appears in different colours as you mentioned. Ive seen aurora borealis many times, and it has always been green. Ive also seen pictures of aurora australis which has manly been purple. Why do they then refer to this experiment as the northern lights, when it is more typically the colours for the aurora australis? What exactly makes the difference for these lights beside that they appear on the northern and southern hemisphere? Is it a big (constant) difference in gas concentrations above each of the poles that effects the spectrum?
     
  5. Jun 10, 2017 #4

    davenn

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    that wouldn't be the norm, rather relatively rare. Only in the really intense displays would purples start to show .......
    Aurora Australis is also primarily green and as the activity intensifies, the reds show, then the yellows and so on

    here's are typical AA from my personal collection, This is from Dunedin, New Zealand

    9811_au2.jpg

    9811_au5.jpg

    I do have some with colour trending towards purple, but these 2 pic's make my point :smile:

    there is no real difference between the aurora seen at each pole

    Dave
     
  6. Jun 11, 2017 #5

    Baluncore

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    Davenn is right.
    Since the nitrogen and oxygen composition of the atmosphere is the same in both the northern and southern hemispheres, and the charged particles are exactly the same, one would expect the light to be identical.

    To human eyes, the colour will always be a false colour since the three different broad-band colour sensors in our eyes are being stimulated by narrow band emissions.

    The apparent colour differences will be due to the variable ability of the eye to see colour at low light levels, by the type of colour discrimination used in the camera that records the image, or by the screen used to regenerate the image, before it is first viewed by human eyes.
     
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