My quick guess is that it is so dim, that our eyes are seeing it mostly with the rods (instead of the cones), which only see black and white. „In the night all cats are gray“
I think a better example probably would just be the night sky (at least in places with non-optimal conditions). Where I'm at there is very little color even when it's clear enough to see galactic features (interstellar cloud/nebulae, clusters of dimmer stars etc).
When it's very very dim your color sensing part of your eyes, which are less sensitive to light, don't work. Only the black and white parts of your vision work.
Uhhhh, I saw them yesterday in northen* hemisphere in Europe and they waren't white at all... So my guess would be that it depends from where you look at it ?
But in reality they are more dull than on pictures, because photographers use Long Exposure to make the color brighter than they actually appear.
A long exposure allows more of the light to be captured but that’s not the reason for the color discrepancy. They really are as colorful as they appear in photos but human night vision is primarily black and white. We just don’t see a lot of color unless it’s sufficiently bright and since auroras are still quite dim in absolute terms, our eyes aren’t capable of recognizing the full intensity of the color.
Hey thanks for the clarification :) ! I'm not a photographer nor educated enough in specific science domain.
I only pointed out what technique photographers use to make them appear so bright and colorful on pictures.
They really are as colorful as they appear in photos but human night vision is primarily black and white.
Does that even make sense? I mean, we are what we are, and we see what we see. There is noway that we could certainly know how they actually look like.
If a reptile looks at an Aurora Borealis, It would totally see it differently, and it's perspective would differ from ours.
With a camera you can change alot of attributes to make it appear b/w, sepia, more light, rgb, cmjn, infrared, flash... But that doesn't make it how they actually appear, I mean who is in charge to give the correct mixture of how much light, b/w, cmjn, rgb, infrared... to see the "real" manifestation ?
Personally, I think this is more a philosophical/metaphysic ¿? question, but I'm no expert in any of those subjects. I'm just relying on my personal experience and my feelings ^^.
It's the green parts that look white / grey. I believe it's more of an illusions - if you have something to contrast it with, such as the moon, you can start to see a slight green tint. The pink I saw last night was very noticeable though.
Rods are more sensitive to light than cones. This is why in low light, colors appear muted. In this context, photographers can adjust the length of exposure to get an image that is more colorful than what our eyes can perceive. Really depends on how bright the aurorae are which can be affected by various factors such as light pollution, solar wind speed, and latitude.
I live too far south to see it but my understanding is that at different layers of the atmosphere, the stellar material interacts with different elements. So, it gets green or pink or whatever depending on how deep it goes.