Color vision in (your?) con-species
Posted: Posted January 14th, 2011 by chiarizio
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If your conworld's atmosphere is like Earth's, can your conspecies see light with a wavelength shorter than 200 millimicrons (frequency as high as 1.5 petahertz (1.5 * 10^15 Hz))?
[color=#555555](Earth's atmosphere is effectively opaque to anything shorter-wavelength or higher-frequency.)

If your conspecies' biochemistry is water-based, can they see light with a wavelength longer than 1450 millimicrons (frequency less than about 207 terahertz (207 * 10^12 Hz))?
[color=#555555](Water is effectively opaque to anything longer-wavelength or lower-frequency.)

If your conspecies is warm-blooded, can they see light with a wavelength longer than 780 millimicrons (frequency less than about 385 terahertz (385 * 10^12 Hz))? If so, how do they keep their eyes cool enough for that?
[color=#555555](Warm-blooded animals' eyes glow at a wavelength about 740 to 780 millimicrons.)

By "see", I mean, they have biological lenses that can focus such EM radiation and form an image their eyes can sense.

RL Earth's color-seeing animals all use a subset of variants of five or six basic optical "pigments";
One (UV or "short 1") has a peak response to light at about 370 millimicrons wavelength;
one (blue or "short 2") has a peak response to light at about 445 millimicrons wavelength;
one (rhodopsin) has a peak response to light at about 498 millimicrons wavelength;
one (green or "medium") has a peak response to light at about 508 millimicrons wavelength;
some New World monkeys have one maximally responsive to "yellow" light, I can't find out exactly which frequency;
one (red or "long") has a peak response to light at about 565 millimicrons wavelength.

Within each color-seeing species there may be mutations that shift the peak response wavelength several millimicrons shorter or longer.

I didn't find any RL species that can see wavelengths shorter than about 300 millimicrons; however, I didn't find anything that says that's theoretically impossible, either.


What are the longest and shortest wavelengths of EM radiation your conspecies can see by? What is the "just-noticeable difference" in wavelengths they can detect -- that is, how close together can two wavelengths be before they no longer look like different colors to your conspecies? Is that answer different in different parts of the spectrum, as might be expected?


Many non-mammalian vertebrates' cone-cells contain oil drops that absorb light either shorter than or longer than their peak-response wavelength; thus they can have up to 12 or 13 different kinds of cone-cells. Each type would have one of up to 4 different kinds of opsin (photosensing pigments); and each type would have either no oil drop or one of up to 5 kinds of oil drop.


Mantis shrimp can also detect differences in polarization of light.


There are 6 Replies

In my scifi conworld, I have creatures that live in space which can see in heat, at quite high resolution (with a 360 field of view), and that are comparatively warm blooded (they run at around 200 C much of the time, but can drop down to the teens in Kelvin when hibernating).

They have heat organs (connected to their furnaces/stomachs) and a kind of dynamic insulation around what amount to tiny screen plates in the eyes where the light is focused by the lens (which is a bit below body temperature, though does radiate a little).

They can vary the conductivity of the insulation. Basically, carbon and aluminates that form microcapillaries which they can constrict (draining the charge, increasing conductivity to near diamond) or expand (pumping it full of a charge, decreasing conductivity to below that of aerogel).

First they dump a large amount of heat into the the plates by constricting the insulation (this gets them hot enough to glow in the visible red- in the neighborhood of 800 C), then they expand the insulation and wait a few seconds for some of the heat to bleed off. The amount of heat that bleeds off in that amount of time depends on what light is focused on them (loss vs. gain).

They can't tell the difference between human visible light and heat with these eyes; it all looks the same to them.

When they reconnect the plates to the heat source by constricting the insulation material, a small metallic membrane generates a differential charge based on the difference in temperature, which is received by nerve endings through organic 'diamond' hairs with heavy metal cores (silver and gold, mostly)- the diamond bleeding off the heat while insulating the 'wire', bringing the contact point down to a more comfortable 200 C (which preserves the nerves).

The hairs are originally flat and plated on one side, which then curl up to form the wire; a genetic condition which results in these hairs not properly curling due to incomplete protein synthesis on the outside of the hair is the most common source of congenital blindness.

That's the closest thing to optical eyes they have; they mostly use these to look at distant stars and astrological bodies for navigation, and to pick up on living things or distant hot rocks.

As to other light,

They also have a number of radio antennas and the ability to generate sharp directional pulses of radio waves (which is how they communicate with each other) and also serves as a form of radar allowing them to sense cold topography and penetrate into material to feel out heavier elements- delicious fissile materials.

They have ionizing light sensing nerves on their skin, which can pick up anything stronger than violet light; UV and gamma up into cosmic radiation, as well as alpha and beta (using slightly different nerves). Felt not unlike our sense of touch. No lenses though.

Posted January 15th, 2011 by Blake
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That's interesting! Really interesting.
Thanks, Blake!
I'd like to read more about them.

Posted January 15th, 2011 by chiarizio
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From what I've seen and read, I think Tarn would would have to be able to see a little farther into near IR than humans, but because of the star their planet circles, and their planet having a slightly thicker atmosphere, I don't think they can see as far into the blue-violet end of the spectrum. But I'm not sure. Maybe there just aren't creatures that see in UV on their planet, unlike here on earth.

Posted January 15th, 2011 by bloodb4roses
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And @anyone else on gtx0 who has a species they’d like to tell us about:

Can you answer the OP about your current con-species?


My Adpihi and Reptigan are Earth-descended Humans. They see color the we do in real life, however that is!

My Space Centipedes can see colors with wavelengths from 200 nanometers to 1450 nanometers.


I hope this isn’t tl;dr.

Edited August 2nd, 2019 by chiarizio
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The World

Of the peoples of Yeola, Daine have the oddest colour vision. Girls are tetrachromats. Theirs is a world of rich hues, saturations, an extra basic colour and a vivid, perhaps almost psychedelic palette. They see best between about 800nm and 280~300nm. Boys are monocrhomats. Theirs is a sepia world of light and shadow and very faded colour. Their colour vision is best between 730~750nm and 980nm.

If you're a guy and think you have difficulties convincing your girl that her skirt is actually blue when she says it's green...have pity on the poor Daine fellow who's entirely lost when she goes on and on about "so this 7ae3db sarong or that 7ae3dc one --- which one compliments my eyes better?"

Posted August 3rd, 2019 by elemtilas
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Posted March 1st by chiarizio
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