Let me rephrase the question – Do we call the Visible Spectrum that because that’s what we can see or is there something different about that part of electromagnetic spectrum (ES) that allow vision to occur. Alternately, If light is dual in nature, being both a wave and a particle, is that the same for other parts of the ES?
Which brings me to the question that I’m most curious about; would it be possible for a creature exist that can see, the same way we see, but using frequencies from other areas of the ES?
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> Do we call the Visible Spectrum that because that’s what we can see
Yes.
> or is there something different about that part of electromagnetic spectrum (ES) that allow vision to occur.
Electromagnetic radiation is all fundamentally the same thing, but different frequencies interact with matter in different ways, for example, any given substance will absorb some frequencies more than others. From a biological perspective, this means that (a) you might need different strucures in your eyes to see different frequency ranges, and (b) some frequency ranges are more valuable for certain purposes than others, e.g. infra red is good for seeing warm objects at night, visible is good for seeing fine detail during the day, etc.
So our eyes evolved to see visible light due to a combination of how useful it is and how easy it is. Other animals can see different frequency ranges because their eyes have evolved in slightly different ways due to different evolutionary pressures.
> Alternately, If light is dual in nature, being both a wave and a particle, is that the same for other parts of the ES?
Yes.
> would it be possible for a creature exist that can see, the same way we see, but using frequencies from other areas of the ES?
Yes. Many animals can see portions of the infra red and/or ultraviolet regions of the spectrum. I don’t think there are any organisms that can see microwaves, radio waves, X rays or gamma rays though. Again, this is due to a combination of how useful it would be and the complexity of the biological structures that would be required.
So lets start with the fact that you’re talking specifically about what **we** can see. The visible spectrum is specific to humans other animals can actually see infrared and ultraviolet. I dont remember what animals can but you can likely find examples.
And no the visible spectrum isnt unique in that the sun also emits other wave lengths they just get refracted by the ozone layer(not all of them do but thats why depending on the location of the sun the sky will be a different color!) so we cant see them but ultraviolet and others are a part of the same spectrum and follow the same basic rules.
The only “difference” is that our eyes arent made to percieve them because wel frankly we dont need to. There is no biological advantage to seeing them for us. Other animals use them to hunt or track but we dont use those wavelengths for it so we didnt evolve to see them.
If stuff is unclear because i am incapable of explaining things please ask i am at a social gathering and any reason to not be social is a good one!
No there’s nothing special about the visible spectrum, those are just the frequencies our eyes respond to. Some animals can indeed see in infrared or ultraviolet (butterflies, bees, mosquitos, some birds, etc). Yes the wave/particle duality applies to all frequencies.
> Do we call the Visible Spectrum that because that’s what we can see
Yes.
> or is there something different about that part of electromagnetic spectrum (ES) that allow vision to occur.
Electromagnetic radiation is all fundamentally the same thing, but different frequencies interact with matter in different ways, for example, any given substance will absorb some frequencies more than others. From a biological perspective, this means that (a) you might need different strucures in your eyes to see different frequency ranges, and (b) some frequency ranges are more valuable for certain purposes than others, e.g. infra red is good for seeing warm objects at night, visible is good for seeing fine detail during the day, etc.
So our eyes evolved to see visible light due to a combination of how useful it is and how easy it is. Other animals can see different frequency ranges because their eyes have evolved in slightly different ways due to different evolutionary pressures.
> Alternately, If light is dual in nature, being both a wave and a particle, is that the same for other parts of the ES?
Yes.
> would it be possible for a creature exist that can see, the same way we see, but using frequencies from other areas of the ES?
Yes. Many animals can see portions of the infra red and/or ultraviolet regions of the spectrum. I don’t think there are any organisms that can see microwaves, radio waves, X rays or gamma rays though. Again, this is due to a combination of how useful it would be and the complexity of the biological structures that would be required.
Yes, there are creatures that can see outside of the human visible spectrum, but not very far. Just a bit into the infrared and the ultraviolet.
As for why we can detect those wavelengths, two main reasons. One, those wavelengths pass through water. As it is believed that life started in the ocean, the first eyes would only have been able to detect light that could penetrate into the ocean.
Second, these wavelengths have the property that they can interact with small molecules. Infrared light and longer wavelengths are too big and weak to effect much, and mostly just scatter off our cells. Ultraviolet light and smaller wavelengths are too small and powerful, and will shoot right through our cells, mostly zipping right through but sometimes causing damage. The wavelengths in between, however, can be absorbed by the right kind of molecule, and the energy of that absorption can be used to send a signal that “hey, I just caught a photon!”
So yes, the visible range does have some special properties that make it suitable for use in vision.
I have heard anecdotal tales of insects being affected by very long wavelengths, like the 120 Hz signal from power lines, but I have not seen any scientific confirmation. It is possible that some creatures can detect wavelengths far from the visual spectrum in some way, but it wouldn’t be in the form of “vision.”
The entire EM spectrum is technically light. The range we can see is “visible light” and there are creatures that see what we cannot such as infrared and ultraviolet
It would be possible (and there likely are) creatures that see entirely in a range inaccessible to us humans without special equipment, but I’m not sure what evolutionary benefit that would have.
Light has the same physics as other parts of the EM spectrum. But it isn’t a complete coincidence that we see the range we see.
Specifically, the range of frequencies we see happens to correspond to the amounts of energy required to bend certain kinds of bond without breaking them. This also happens to be a range of frequencies in which most stars emit their light. “Seeing” things that break bonds would be hard, since that would require the production of new molecules. And seeing things that can’t really interact with molecules easily would be even harder. So that limits sight of the kind we have to a fairly narrow window around the visible range, although that range is wider than the range we actually see (some animals can see IR or UV that we can’t).
That said, if we lived on a planet where the primary sort of illumination were different, we would probably have evolved very different senses.
The answer is both simple and complex: we call it the visible spectrum because that’s what we see. Other animals can see further into the ultraviolet or infra red; antennas can induce current from frequencies even further up the spectrum where we wouldn’t be able to sense individual photons of energy as easily.
The wavicle concept of radiation is consistent for the entire EM spectrum however.
As for creatures seeing in other areas of the spectrum: that’s where it gets tricky. Many animals can “see” electrical currents with sensors attuned to other areas of the spectrum: the most notable are sharks. Pigeons can “see” the earth’s electromagnetic field. Even we humans can “see” infra red with the nerves in our skin.
What you’ll notice there is that the physical properties required to sense EM radiation differ up and down the spectrum because of how the different frequencies interact with the very limited set of atoms (and therefore electron shells) that can exist.
Yes, there are creatures that can see outside of the human visible spectrum, but not very far. Just a bit into the infrared and the ultraviolet.
As for why we can detect those wavelengths, two main reasons. One, those wavelengths pass through water. As it is believed that life started in the ocean, the first eyes would only have been able to detect light that could penetrate into the ocean.
Second, these wavelengths have the property that they can interact with small molecules. Infrared light and longer wavelengths are too big and weak to effect much, and mostly just scatter off our cells. Ultraviolet light and smaller wavelengths are too small and powerful, and will shoot right through our cells, mostly zipping right through but sometimes causing damage. The wavelengths in between, however, can be absorbed by the right kind of molecule, and the energy of that absorption can be used to send a signal that “hey, I just caught a photon!”
So yes, the visible range does have some special properties that make it suitable for use in vision.
I have heard anecdotal tales of insects being affected by very long wavelengths, like the 120 Hz signal from power lines, but I have not seen any scientific confirmation. It is possible that some creatures can detect wavelengths far from the visual spectrum in some way, but it wouldn’t be in the form of “vision.”
I think some of the posts miss a few details about why 100s of nanometres is a good place to be able to “see”.
Any shorter and we’re in the ionising range, any longer and proteins would have to be too large to detect them (and photon energies would be too low).
Thankfully the atmosphere allows only light (and a little UV and IR) through so that’s what evolution has worked around. Proteins are just the right size to work as detectors.
Alien planets using familiar carbon based life could evolve around longer wavelengths for “sight”, but something needs to block ionising radiation.
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