Thread: Vision

Originally Posted by Schmaven

Of the entire electromagnetic spectrum, our eyes allow us to see just a narrow band of the energy that all matter emits. What would it be like if that range was extended somehow and we could see not just colors, but all wavelengths of what is emitted? I think it's interesting how our brains distinguish the minute differences in wavelengths as completely different colors. If our eyes let us see radio waves and such, what would they look like?

Try LSD, it could give you a rough idea.

What does sound look like?

You see light waves with your eyes,
you hear sound waves with your ears.
the odds are if you were to have a new sense for a different wavelength it would not be via your eyes.

Oh, and you feel regular waves (vibrations) with your body.

Originally Posted by Sandform

What does sound look like?

You see light waves with your eyes,
you hear sound waves with your ears.
the odds are if you were to have a new sense for a different wavelength it would not be via your eyes.

Oh, and you feel regular waves (vibrations) with your body.

Congratulations, you've just killed physics.

Sound waves are not the same as light (electromagnetic) waves.

As for your last statement, you also feel them with your ears. Ever wondered why loud music literally "shakes the room"? You need help, friend, educational physics help!

Originally Posted by Identity X

Congratulations, you've just killed physics.

Sound waves are not the same as light (electromagnetic) waves.

As for your last statement, you also feel them with your ears. Ever wondered why loud music literally "shakes the room"? You need help, friend, educational physics help!

Yeah lets pretend I didn't know everything you just said.

I wasn't even equating sound waves to the same as light waves.

I read through his post quickly and all I noticed was that he was wondering what it would be like to experience something that sight can't see.

"Ever wondered why music literally shakes the room?"
Yeah I sooo didn't know that. Get over yourself you asshole.

I know the basics of physics and you are just a total jerk. I was only making the point that you have sense for more than just sight, and you experience things differently.

Sorry, I thought that since you where talking about visible light being picked up through the eyes and sound picked up through the ears, so different wavelengths should be picked up in another organ, you were saying that sound was like light but at different wavelengths. That's what it still reads like, to me, and I think to most people. Either you're trying to cover it up or you should have clarified your point further. It wasn't a very persuasive argument.

Even so, the retinas pick up EM waves. They just happen to pick up roughly red, green and blue colours, and luminence. If we were able to pick up further ranges of wavelength, would it not make sense to change the cell make up in the retina? Rather than invent a new organ entirely.

Originally Posted by Identity X

Even so, the retinas pick up EM waves. They just happen to pick up roughly red, green and blue colours, and luminence. If we were able to pick up further ranges of wavelength, would it not make sense to change the cell make up in the retina? Rather than invent a new organ entirely.

Exactly. It would just be new visual phenomenon, possibly new colors.
I really don't know anything about this, but I figure that a new pattern in the brain would allow for new colors to exist.

Which brings me to the question: Is it actually possible to experience new colors under the influence of psychoactive hallucinogenic drugs? I don't know because I've never taken a true hallucinogenic.

What's up with that "feeling" you get when you sometimes enter a room you have never been before? you begin to shake, and you hear this high pitch
noise in your ears, and you feel all weird. That's just from sometimes entering a room you have never been in before...

Our eyes simply acquired the ability to associate a color with a wavelength. In reality these wavelengths have no color. It's speculation as to how our eyes would allow us to see other wavelengths. It would give rise to new visual aspects that could exist alongside color.

Originally Posted by LucidFlanders

What's up with that "feeling" you get when you sometimes enter a room you have never been before? you begin to shake, and you hear this high pitch
noise in your ears, and you feel all weird. That's just from sometimes entering a room you have never been in before...

See a doctor?

Also, the topic of the thread is increased perception of the electromagnetic spectrum. You post has nothing to do with that at all.

Congratulations, you've just killed physics.

Sound waves are not the same as light (electromagnetic) waves.

As for your last statement, you also feel them with your ears. Ever wondered why loud music literally "shakes the room"? You need help, friend, educational physics help!

No he doesn't. They're both waves but we percieve the frequency of one as a colour but the frequency of the other as a pitch, which is the whole point of the thread.

I haven't studied optics yet, but I always find it confusing. Why is it that every object we come across tends to emit a wavelength in the very narrow band which we percieve? Is it that only a narrow set of wavelengths are reflected by solid objects and the eye has evolved to percieve most of these?

Originally Posted by Xei

No he doesn't. They're both waves but we percieve the frequency of one as a colour but the frequency of the other as a pitch, which is the whole point of the thread.

Uhh... water waves are also waves... the point is that they are fundamentally different: electromagnetic radiation can move through vacuum while sound waves need a medium in which to move.

I haven't studied optics yet, but I always find it confusing. Why is it that every object we come across tends to emit a wavelength in the very narrow band which we percieve? Is it that only a narrow set of wavelengths are reflected by solid objects and the eye has evolved to percieve most of these?

Most objects don't emit light, they reflect specific parts of the light that is cast upon them and absorb others. There are a couple of reasons for why this spectrum works for the eye:

1. The sun (and all customary light sources) emit electromagnetic radiation that contains those parts of the spectrum that your eye can pick up on.

2. The eye evolved to pick up these frequencies through evolutionary adaptation, not the other way around. As should be known, the sun emits ultraviolet radiation as well. UV glow sticks weren't all that common back in the savanna, so you can't see it. Simple.

3. I particular, the range of frequencies your eyes are responsive to, is in the area where it makes most sense for the simple identification of objects. Microwaves, nuclear radiation, radio waves and all that jazz actually penetrate most matter so what's the point of being responsive to them? You wouldn't see anything except satellites and mobile phones. Additionally, the sun doesn't emit any of those, so you wouldn't see jack shit anyway.

With the range that the eyes are built to perceive you can actually identify rocks and tigers and such. That's quite helpful, in evolutionary terms. Objects weren't specifically made to reflect these frequencies, they just do.

Here is the spectrum of electromagnetic radiation emitted by the sun.


Some animals can perceive infrared light. BUT, infrared doesn't give "colors", because infrared is usually emitted rather than reflected. You get heat vision. With infrared, you can't see whether an apple can still be eaten or not. You can only see if someone has recently put it in an oven or not.


Do you see how it all comes together? The reason why our eyes only perceive such a small range of the electromagnetic spectrum is that that's really the only part of it that makes sense to us as humans. Other animals that hunt in the dark (some snakes) profit from seeing warmth rather than color.

Yes that's what I thought. A few questions though:

1. So, if you fire electromagnetic waves of all frequences at an object, it'll only reflect (I didn't mean to write emit down first time, sorry, I know that light's reflected) wavelengths in a thin band (400-700nm)? Why is it that the sun also tends to emit these frequencies?

2. What causes objects to absorb or reflect specific frequencies? (A quantum answer I suppose?).

3. Do we percieve objects that only emit UV waves as black?

4. Do transparent materials like water or glass neither absorb or reflect light / why so?

5. Do black materials not reflect any wavelengths / why?

6. Why do some materials reflect multiple wavelengths (purple etc.)?

7. Why do some materials reflect all wavelengths (white)?

8. Why do some materials reflect light and what is the difference between these and white materials?

Thanks.

Uhh... water waves are also waves... the point is that they are fundamentally different: electromagnetic radiation can move through vacuum while sound waves need a medium in which to move.

Yes, I'm not a dummy, what I said was that the discussion's really about qualia and not physics.

Originally Posted by Xei

1. So, if you fire electromagnetic waves of all frequences at an object, it'll only reflect (I didn't mean to write emit down first time, sorry, I know that light's reflected) wavelengths in a thin band (400-700nm)?

It really depends on the material in question. Black stuff doesn't reflect it while I guess some sort of high-quality reflective surface (silver or whatever) will reflect more than just visible light.

Why is it that the sun also tends to emit these frequencies?

Well, luck. :p That's one of those questions that are kind of related to abiogenesis. If the sun didn't emit those frequencies, life wouldn't be on this planet and you wouldn't ask the question. Maybe some other life form would be on another planet and wondering why their sun is so awesome as to enable life. It's one of incredibly many suns and others radiate much different wave lenghts. It is only because our sun radiates this kind of light, it is possible for you to even ask why it does it.

2. What causes objects to absorb or reflect specific frequencies? (A quantum answer I suppose?).

I don't know. :p I think it has something to do with electrons hopping from A to B or something. It's a load of stuff on atomic level, you'd have to study that...

3. Do we percieve objects that only emit UV waves as black?

Yes.

4. Do transparent materials like water or glass neither absorb or reflect light / why so?

Well, both water and glass reflect light very much. Air would probably be a more accurate example. I can't give you the exact chemical scoop on this but at least for gases you have to consider that the molecules are much farther apart. They still refract the light though, you just don't notice.

5. Do black materials not reflect any wavelengths / why?

Yes. I don't know why. Study physical chemistry.

6. Why do some materials reflect multiple wavelengths (purple etc.)?

The colors you see are almost exclusively combinations of loads of different wave lengths overlapping. All of this works in spectra. Any consumer-range LCD monitor works with a backlight that produces a white that is kinda like this:

So you never really get to see any "pure" color. It would be impossible to produce and the intensity of the colors would probably melt your eyeballs.

Again, study chemistry, because I don't know.

7. Why do some materials reflect all wavelengths (white)?

8. Why do some materials reflect light and what is the difference between these and white materials?

Pass.

I'll try to clear some things up in here, starting from the top. Not sure what was meant by 'wavelengths don't have color'. Our brains do not associate certain colors with certain wavelengths; colors would not exist without those wavelengths. Color is a reaction to and interpretation of specific wavelengths. The best way to describe what electromagnetic waves outside the visual spectrum might look like if we could see them is wavelengths longer than red (radio, infrared, etc) would look more red than blue and higher wavelengths (ultraviolet, microwave, gamma, etc) would look more blue or violet than red. Other than that, there is no way to describe their 'color' although they do have one.

In order for us to see different wavelengths, we would most likely not need a new organ, but new types of cone cells in our eyes that were sensitive to higher or lower lengths. Most humans have 3 types of cone cells, but some people and some types of animals have 4. The extra one doesn't allow them to see higher or lower than the visual spectrum however, and just gives them more refined differentiation between normal colors.

Different objects reflecting different colors of light is due to the material only absorbing certain wavelengths. Every substance absorbs specific wavelengths and reflects others, and can actually be identified by what light it reflects. The reasons why materials absorb some colors and not others are complicated but its basically due to the amount of energy each wavelength carries and how much energy the substance needs to absorb. If you want to read more about it, read about the Beer-Lambert law.

I see I missed a few questions.

Most materials reflect wavelengths outside the visual spectrum; you just can't see them. This is how infrared and ultraviolet vision electronics work. Infrared vision detects heat, and ultraviolet goggles shine a ultraviolet light on objects, and then is capable of detecting the light that reflects and translates it into a visible color.

Light reflection occurs when the light goes from one medium to a different one that has a different index of refraction. Transparent mediums such as water and light reflect some of the light, absorb some of the light, and let some of the light pass through or reflect/refract/re-emit some of the light in the same direction as it was already going. Water or glass will still be reflective because some of the light was refracted back when it changed mediums and some was not.

Originally Posted by Xei

No he doesn't. They're both waves but we percieve the frequency of one as a colour but the frequency of the other as a pitch, which is the whole point of the thread.

Idiot. By the questions you asked later it is clear you have no higher understanding of physics, so why try and pretend you do?

Originally Posted by Identity X

Idiot. By the questions you asked later it is clear you have no higher understanding of physics, so why try and pretend you do?

No need to start throwing insults, especially if you don't have a degree to back yourself up. It looks like everyone here is pretty much on the layman level so its okay to keep it friendly.

Originally Posted by Xaqaria

No need to start throwing insults, especially if you don't have a degree to back yourself up. It looks like everyone here is pretty much on the layman level so its okay to keep it friendly.

Well, one should at least know what they are talking about if they are going to tell someone they are simply wrong.

Physics was academically my strongest subject at "advanced level" (16-18) getting a high A in it but I chose not to take a degree in it because I could not bear another equation. I do not regret this decision .

Idiot. By the questions you asked later it is clear you have no higher understanding of physics, so why try and pretend you do?

One should at least know what they are talking about if they are going to tell someone they are simply wrong.

- If you could actually take a time out and read what I said, I never said you are wrong, I said you were missing the point of the conversation, which is about differences in perception of waves and not the physics of them, which is relatively irrelevant.
- I understand completely the difference between electromagnetic waves and physical waves involving the displacements of matter, having studied waves quite thoroughly. However I've never studied optics and it's actually quite a cloudy area anyway. Note though that I provided half the answers to my questions anyway and the rest required degree level knowledge for an answer.
- You are a stuck up twat and anybody who does not get a high A in physics should be locked away; asides from the mechanics module in maths it's the most ridiculously easy waste of time of a qualification I've ever seen and it boggles the mind that an A is supposed to class somebody as intelligent in this country. God only knows what the people who fail are like.

Xaquaria: about reflection. I've always been told that for reflection to occur, you must be viewing a ray incident at an angle greater than the critical angle. However this really conflicts with common experience because you can, for example, see your own eye, from which the reflected rays are hitting the material at an angle of 0, and using Snell's law, the sin of that angle is also 0, so the ratio of the refractive indexes between the backing material and the glass of the mirror would have to be x / infinity, which is impossible..? And also that's just an equation, not really a physical explanation?

Originally Posted by Xei

- You are a stuck up twat and anybody who does not get a high A in physics should be locked away; asides from the mechanics module in maths it's the most ridiculously easy waste of time of a qualification I've ever seen and it boggles the mind that an A is supposed to class somebody as intelligent in this country. God only knows what the people who fail are like.

Are you trying to be ironic by calling me a stuck up twat and then writing that? If you are being serious, you are the stuck up twat.

And about everything else, I interpreted your message wrong and my reply unwarranted, I apologise.

BTW I got a D in AS Mechanics, but a perfect mark in Physics, very strange .

Yeah I apologise for that, I was just a bit taken aback by the sudden insult...

And I was being a bit stuck up really yeah, in the process of trying to demean you perhaps.

But I do find it difficult to understand the people who, after a year of doing it, still don't seem to have any idea how you find the components of a force and things... or answer the same old questions which invariably come up on every single paper... but oh well. I've done my maths A level early so that's probably why it all looks stupidly easy to me.

Well if this question is similar to what colors would look like that we never seen before I believe the answer is that, our brains just happened to see colors the way we do, we actually see a color in a certain way because thats are brains way of telling them apart, our brain could have evolved to tag any spot of the visual spectrum of light to any 'look', we could have seen green as purple if we evolved to do so, and thats how our minds chose to mark it.

Now seeing other electromagnetic energy would be similar, we could see it as anything, it's just a matter of what our brains evolve to mark it as.

I reckon there could be 'additional' qualia. A person who's only ever seen yellow and red before would presumably only know of those two vision qualia, but somebody who has seen yellow, red, and blue, knows of three qualia... it doesn't seem out of the question that you can keep adding quale upon quale.

It's all very interesting and mysterious though; why do we even need qualia in the first place? Why can't we just percieve colour like pitches of sound, after all, they're both just waves with different frequencies? Why does the brain separate this continuous band into distinct sections?

That's the thing I want to be studying in my future career, actually. Theoretical and computational neuroscience...

Originally Posted by Xaqaria

I'll try to clear some things up in here, starting from the top. Not sure what was meant by 'wavelengths don't have color'. Our brains do not associate certain colors with certain wavelengths; colors would not exist without those wavelengths. Color is a reaction to and interpretation of specific wavelengths.

I don't have a degree in physics or anything but you have me a bit confused with a lot of contadiction. Am I not getting something? I know I word stuff funny sometimes.

Unless of course you took my statement literally>Wavelengths have color because we see them. I was saying without us there would be no biological setup for making colors. Am I correct in assuming everything we see is what our body has developed?

Originally Posted by NeoSioType

I don't have a degree in physics or anything but you have me a bit confused with a lot of contadiction. Am I not getting something? I know I word stuff funny sometimes.

Unless of course you took my statement literally>Wavelengths have color because we see them. I was saying without us there would be no biological setup for making colors. Am I correct in assuming everything we see is what our body has developed?

Wait, what are these contradictions?