Why do Aurora colors in a bottle resemble Aurora Australis?

AI Thread Summary
The discussion centers on the characteristics and color variations of auroras, specifically comparing the Aurora Borealis and Aurora Australis. Participants note that the changing colors in auroras are primarily due to the ionization of oxygen and nitrogen atoms, which emit specific colors like red and green. These colors can mix to create additional hues, such as purple and yellow, particularly during intense displays. While there is a perception that Aurora Borealis is predominantly green and Aurora Australis often appears purple, it is clarified that both auroras primarily exhibit green light, with other colors appearing under specific conditions. The discussion also addresses the misconception that there are significant differences in the auroras at the poles, emphasizing that the atmospheric composition and charged particles are similar, leading to comparable light emissions. Variations in perceived color can result from human vision limitations, camera settings, and display technology rather than inherent differences in the auroras themselves.
Earth sciences news on Phys.org
Solomei said:
I would say that this looks more like Aurora Australis.

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

Solomei said:
What is the reason for these changing colors?

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 bluesDave
 
davenn said:
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 bluesDave
Im trying to figure this out. I know that aurora appears in different colours as you mentioned. I've seen aurora borealis many times, and it has always been green. I've 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?
 
Solomei said:
Ive also seen pictures of aurora australis which has manly been purple.

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:

Solomei said:
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?

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

Dave
 
  • Like
Likes Solomei
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.
 
  • Like
Likes BillTre and Solomei
Thread 'The Secrets of Prof. Verschure's Rosetta Stones'
(Edit: since the thread title was changed, this first sentence is too cryptic: the original title referred to a Tool song....) Besides being a favorite song by a favorite band, the thread title is a straightforward play on words. This summer, as a present to myself for being promoted, I purchased a collection of thin sections that I believe comprise the research materials of Prof. Rob Verschure, who at the time was faculty in the Geological Institute in Amsterdam. What changed this...
These last days, there is a seemingly endless cluster of rather powerful earthquakes close to the islands of Santorini, Amorgos, Anafi, and Ios. Remember, this is a highly volcanically active region, Santorini especially being famous for the supervolcanic eruption which is conjectured to have led to the decline of the Minoan civilization: https://en.m.wikipedia.org/wiki/Minoan_eruption To grasp the scale of what is happening, between the 26th of January and the 9th of February, 12000...
Back
Top