I was just wondering, is it possible that in some stars in the universe, or even other dimensions, there are colours that are completely different from our colour spectrum? Even if there was, I find it almost impossible to imagine such a colour. What do you think?

All electromagnetic radiation (including light) is on the same spectrum. This is universal - it's just numbers. There's a frequency of EMR for every positive real number.

Color, on the other hand, is related more to biology than to physics, more to the observer than the emitter.

We are limited in the colours we see because we have only three types of colour detecting cells, and each type has a limited response range.

Some people (all females) have four colour detecting cell types, and these people (tetrachromats) can distinguish colours that other people can't. Ie two colours that look identical to you could look quite different to a tetrachromat.

Some animals also have more colour detecting cell types. I think birds have four, and some insects might have five (?not sure?). Many animals have a broader detection range as well - many insects can see into the ultraviolet, for example.

Anything's possible, but trying to imagine new primary colours created through alien light frequencies, is like trying to imagine new types of sound frequencies that are completely different from the normal bass, middle, treble and their derivatives and as we have never experienced any of these things, it would be impossible to actually imagine them.

I don't know about new colours, per say. But the gradual change in what we do see in our atmosphere is worth attention, such as partical rainbows, doublet rainbows, spiral clouds with spectral emanations.
http://epod.usra.edu/archive/images/cirruscloud.jpg

edited: to fix image addy

All electromagnetic radiation (including light) is on the same spectrum. This is universal - it's just numbers. There's a frequency of EMR for every positive real number.

Color, on the other hand, is related more to biology than to physics, more to the observer than the emitter.

We are limited in the colours we see because we have only three types of colour detecting cells, and each type has a limited response range.

Some people (all females) have four colour detecting cell types, and these people (tetrachromats) can distinguish colours that other people can't. Ie two colours that look identical to you could look quite different to a tetrachromat.

Some animals also have more colour detecting cell types. I think birds have four, and some insects might have five (?not sure?). Many animals have a broader detection range as well - many insects can see into the ultraviolet, for example.

Yes, I am quite aware of that Pete. I think you misunderstood what I was really asking. I mean is it possible there is an electromagnetic spectrum completely different to the one we observe. I also think it is universal, but sometimes it makes me wonder. In another part of the universe, or another dimension, could there be an EMR completely different from our own.

Another thing to ponder: once we surpass ultraviolet frequency, what other colours become available, or do they not?

The part of the electromatic spectrum we are able to percieve is only very tiny. We can't see X-rays, or Gamma rays, but if we could they would probably be interpreted as colours we've never seen before. If it's possible to perceive different wave lenghs lengths, such as gammarays, then we would have to modify our brains in order to see them.

we know the extent of the EM spectrum.
anyother form of ray would have to find a way of moving that is neither particle (photons and the like) or waves (gamma rays etc). i really dont have a clue what this could be, unless it travells in like another dimension or something. this would be the only way to have more colours, i.e. a new form of wave we have not detected.
i suppose there are infinite shades of colours, but thats probably not what you were after....

o and by the way if we interpreted x rays and stuff they would have to be in the light spectrum otherwise we still wouldnt see them!! lol

Yes, I am quite aware of that Pete. I think you misunderstood what I was really asking. I mean is it possible there is an electromagnetic spectrum completely different to the one we observe. I also think it is universal, but sometimes it makes me wonder. In another part of the universe, or another dimension, could there be an EMR completely different from our own.
No. If there was something completely different, it wouldn't be EMR.


Another thing to ponder: once we surpass ultraviolet frequency, what other colours become available, or do they not?
The spectrum goes on forever, if that's what you mean. UV-A,B,C could possibly be considered different colours, but colour doesn't really mean anything except in the context of a particular detector. If there's no eye that can detect it, is it really a colour?


Here's something to ponder... Do bats and dolphins perceive "colours" in sonar? That might be close to the original question, come to think of it.

A similar discussion took place recently in this thread:
http://www.sciforums.com/showthread.php?t=33476

For us, limited by the EM range of our eyes and the faculties of our visual cortex, trying to imagine entirely alien colours is like a person born blind trying to understand any type of colour.

Animals with a sonar sense probably do interpret the varying data from the surfaces of different objects in a fashion analagous to visual colors, or auditory pitch and tone. If dolphins ever suffer from synesthesia, no doubt then they will derive colors from what they sense!