Would you go blind if you became invisible?

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Would you go blind if you became invisible?

Postby King Author » Tue Jul 05, 2011 2:04 am UTC

So getting lost Googling lead me to this Cracked 50 Reasons Lord of the Rings Sucks article. Relax, geeks -- it's a joke. Took me 'til number nine to realize it >_> Anyway, it still manages to bring up a very interesting - and to my novice ears, plausible - theory concerning invisibility, so I need ya'll to tell me what you think of it.

Every time Frodo or Bilbo went invisible with the ring they should have also gone BLIND. Your eyes cannot function unless light is reflected off the cornea. If light passes through it (as must be the case with invisibility) sight is no longer possible.

Is that true? If you were magically made totally invisible (invisible not via tech-y camouflage but by light literally passing right through you instead of reflecting off), would you be unable to see?

Related: How cool is that invisibility cloak? My vote is for "very."
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Re: Would you go blind if you became invisible?

Postby BlackSails » Tue Jul 05, 2011 2:11 am UTC

A wizard did it.

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Re: Would you go blind if you became invisible?

Postby thoughtfully » Tue Jul 05, 2011 3:57 am UTC

Well yeah, if all the light is passing through you, you won't be able to see anything, since the light has to be absorbed to jostle electrons around and make a signal for your vision cortex to play with. But clever things might be done by absorbing just enough light very evenly, or peeping through a tiny pinhole, etc. Detectable in principle, but maybe not so much in practice, under favorable conditions.
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Re: Would you go blind if you became invisible?

Postby Minerva » Tue Jul 05, 2011 3:59 am UTC

I will point out here that in Quake, the Ring of Shadows makes you invisible... except for your eyes. :)
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Re: Would you go blind if you became invisible?

Postby Izawwlgood » Tue Jul 05, 2011 4:20 am UTC

I remember reading something about how certain species of shrimp or deep sea fish (or maybe insects? this is spiraling towards 'I may not have a clue what I'm talking about') utilize eye stalks to keep their pigmented, visible eyes, separate from their largely transparent bodies.
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Re: Would you go blind if you became invisible?

Postby Ankit1010 » Tue Jul 05, 2011 9:44 am UTC

What if your eyes were invisible in the sense that they somehow just absorbed all the light coming to them instead of letting it go through? Like maybe some kind of way to make all light coming to your eyes undergo Total Internal Reflection?

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Re: Would you go blind if you became invisible?

Postby AvatarIII » Tue Jul 05, 2011 9:46 am UTC

there's always the option of the invisible person seeing in a normally non-visible spectrum, or say letting through 50% of the light at just the pupils making the dark, and therefore hard to see anyway, pupils semi transparent, and allowing the invible person to see at 50% light, which is easy enough

Ankit, if your eye's absorbed all the light, they would be black, not transparent.

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Re: Would you go blind if you became invisible?

Postby Xanthir » Tue Jul 05, 2011 3:00 pm UTC

Ankit1010 wrote:What if your eyes were invisible in the sense that they somehow just absorbed all the light coming to them instead of letting it go through? Like maybe some kind of way to make all light coming to your eyes undergo Total Internal Reflection?

Then they'd look black. That's the *definition* of black.
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Re: Would you go blind if you became invisible?

Postby EricH » Tue Jul 05, 2011 4:35 pm UTC

There's another problem with the original statement:
King Author wrote:Every time Frodo or Bilbo went invisible with the ring they should have also gone BLIND. Your eyes cannot function unless light is reflected off the cornea. If light passes through it (as must be the case with invisibility) sight is no longer possible.
Although some light is reflected off the cornea, its function in vision is to be transparent; the same with the lens. The retina is the part that has to absorb light (not reflect it). Specifically the rods and cones--the light-sensitive cells embedded in the retina. If everything but those light-sensitive cells were invisible, you'd still be blind, because they'd be subjected to incoming light from all angles, including from behind, and there would be no way to form an image of objects in front of you, on the retina. Really, the cornea is just about the only part of the eyeball that could be made invisible, without severely affecting your vision.

On the topic of reflection, another bit of optical biology: some animals, like cats, do have reflective cells as part of their vision system--because the light-sensitive cells aren't completely opaque, some light does get through them. The reflective layer of cells sits behind the layer of rods, and bounces the extra light back through them, which gives the rods a second chance to absorb the light. This is why cats have very good night vision, and why their eyes shine--if you're holding a candle in the dark, and a cat looks at you, its eyes work like two tiny mirrors. But, if those cells became invisible, instead of reflective, the cat could still see, it would just need more light to do so.
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Re: Would you go blind if you became invisible?

Postby Angua » Tue Jul 05, 2011 4:43 pm UTC

I assumed he meant light wouldn't be able to refract through the cornea if you were truly invisible - that would severely interfere with the ability of light focusing on the retina.

but yes, if you were truly invisible, you shouldn't be able to see, either because the light wouldn't be interacting with you, or because it would passing around you. Generally, we forget about this, as invisibility is otherwise awesome as a super power.
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Re: Would you go blind if you became invisible?

Postby Adam Preston » Tue Jul 05, 2011 6:15 pm UTC

By invisible you mean the ability for light to pass through you making you transparent, which of course yes you would be blind as no light would be picked up by the eyes.
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Re: Would you go blind if you became invisible?

Postby iChef » Tue Jul 05, 2011 6:51 pm UTC

Predator makes a lot more sense now. He has the invisible shield up, but can still see infared.
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Re: Would you go blind if you became invisible?

Postby ++$_ » Tue Jul 05, 2011 7:50 pm UTC

The answer to the question in the title is, "It depends on whether the thing that made you invisible is incredibly poorly designed. If so, it could cause you to go blind. Otherwise, it won't." As it turns out, Sauron employed some pretty good engineers, so the One Ring is very well designed. (In fact, it was built to be shock-proof and lava-resistant down to 50 meters.)

The way it works is very simple. When light strikes your retina, it is absorbed like normal. Then, the One Ring causes the exact same pattern of light to be emitted by the other side of your head.

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Re: Would you go blind if you became invisible?

Postby EricH » Tue Jul 05, 2011 8:34 pm UTC

Angua wrote:I assumed he meant light wouldn't be able to refract through the cornea if you were truly invisible - that would severely interfere with the ability of light focusing on the retina.
Now, that's a worthwhile argument; the lens provides much of the refraction needed for focusing, and more is provided by the cornea--but if the cornea had the same refractive index as air, wouldn't the boundary between it and the aqueous humor provide most of the necessary refraction? Put another way, is the cornea's thickness relatively constant, or does it thin in the center? The worst case scenario is nearsightedness, but my own knowledge of optical anatomy gives out at this point, so I don't know whether it's enough to be called 'severely impaired'.

++$_ wrote:The way it works is very simple. When light strikes your retina, it is absorbed like normal. Then, the One Ring causes the exact same pattern of light to be emitted by the other side of your head.
In a world that includes quantum mechanics, that means the pattern of light is absorbed before reaching the eye, then duplicated and retransmitted both to the eye and the back of the head. Can't detect the pattern without affecting the pattern, after all. This scheme sounds like tech-y camouflage, which the OP specifically excluded.
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Re: Would you go blind if you became invisible?

Postby gmalivuk » Tue Jul 05, 2011 10:15 pm UTC

No, it's not technological camo, it's magical camo. And if we're not allowing magic *or* technology, then the question is pointless to begin with, because invisibility is impossible.
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Re: Would you go blind if you became invisible?

Postby Angua » Tue Jul 05, 2011 10:25 pm UTC

The cornea provides the majority of focusing on to the retina actually - the lens is more for fine focusing rather than doing the bulk of the work - the cornea is what allows you to see if you have longsightedness when your lens doesn't work properly anymore and gets stretched out and thin. Changes in the thickness of the cornea can give rise to astigmatism and other imperfections of sight (it's kind of cool that when you have laser eye surgery they correct most of this, leading to better night vision as more light is being focused from all directions instead of just the front).

I don't know the exact refractive index of the cornea, but I doubt it's the same as air - it would probably be closer to aqueous humour.
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Re: Would you go blind if you became invisible?

Postby torontoraptor » Tue Jul 05, 2011 10:27 pm UTC

++$_ wrote:The answer to the question in the title is, "It depends on whether the thing that made you invisible is incredibly poorly designed. If so, it could cause you to go blind. Otherwise, it won't." As it turns out, Sauron employed some pretty good engineers, so the One Ring is very well designed. (In fact, it was built to be shock-proof and lava-resistant down to 50 meters.)

The way it works is very simple. When light strikes your retina, it is absorbed like normal. Then, the One Ring causes the exact same pattern of light to be emitted by the other side of your head.


Close, but not quite. What Sauron and his team of engineers ACTUALLY did was shift what spectrum of light you see and are visible in. Hence the Wraiths being able to see Frodo, and Frodo being able to see them, when everyone else just saw some cheap black robes.
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Re: Would you go blind if you became invisible?

Postby Aelfyre » Wed Jul 06, 2011 12:49 am UTC

Another point I haven't seen mentioned unless I missed it.. if you are invisible a.k.a. 100% transparent with no refraction to light a.k.a. electromagnetic radiation you might almost immediately freeze solid since your body would no longer absorb any IR light or Thermal Energy and would bleed everything away fairly quickly I am thinking.

hmm that's actually another point in order to be truly "invisible" in addition to dealing with reflected/refracted external light you would need to somehow contain all the IR you normally radiate.
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Re: Would you go blind if you became invisible?

Postby Xanthir » Wed Jul 06, 2011 5:28 am UTC

If you were transparent to *all* electromagnetic radiation, then yeah, you wouldn't be able to absorb radiant heat from the environment. You could still pick up heat from objects and the air via conduction.

You definitely wouldn't "almost immediately freeze solid", though. You'd lose heat slower than you would in a vacuum (again, because conduction is still warming you at least somewhat), and vacuum takes some time to freeze you. Meat holds quite a bit of heat, after all; plus, until you die of hypothermia, your body is still producing heat.
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Re: Would you go blind if you became invisible?

Postby King Author » Wed Jul 06, 2011 7:24 am UTC

Izawwwlgood wrote:I remember reading something about how certain species of shrimp or deep sea fish (or maybe insects? this is spiraling towards 'I may not have a clue what I'm talking about') utilize eye stalks to keep their pigmented, visible eyes, separate from their largely transparent bodies.

The only deep sea shrimp with special eyes I know is the Mantis Shrimp, which can pretty much see the entire electromagnetic spectrum, and it has its eyes on stalks, but I don't think its body is transparent.

AvatarIII wrote:there's always the option of the invisible person seeing in a normally non-visible spectrum, or say letting through 50% of the light at just the pupils making the dark, and therefore hard to see anyway, pupils semi transparent, and allowing the invible person to see at 50% light, which is easy enough

The "let your eyes see in a non-visible spectrum" thing would only be useful if humans could be perceived in that part of the spectrum. Maybe X-Ray? Nah, then you'd have radiation to worry about. Ultra-violet?

EricH wrote:On the topic of reflection, another bit of optical biology: some animals, like cats, do have reflective cells as part of their vision system--because the light-sensitive cells aren't completely opaque, some light does get through them. The reflective layer of cells sits behind the layer of rods, and bounces the extra light back through them, which gives the rods a second chance to absorb the light. This is why cats have very good night vision, and why their eyes shine--if you're holding a candle in the dark, and a cat looks at you, its eyes work like two tiny mirrors. But, if those cells became invisible, instead of reflective, the cat could still see, it would just need more light to do so.

Do you think surgery to give humans cat-like eyes would ever be possible? 'Cause I really want cats eye vision.

Angua wrote:but yes, if you were truly invisible, you shouldn't be able to see, either because the light wouldn't be interacting with you, or because it would passing around you. Generally, we forget about this, as invisibility is otherwise awesome as a super power.

Heh, good answer.

iChef wrote:Predator makes a lot more sense now. He has the invisible shield up, but can still see infared.

99% sure they didn't realize that when they were shooting it, though :p

torontoraptor wrote:Close, but not quite. What Sauron and his team of engineers ACTUALLY did was shift what spectrum of light you see and are visible in. Hence the Wraiths being able to see Frodo, and Frodo being able to see them, when everyone else just saw some cheap black robes.

Having never read the books, I just assumed what the One Ring actually did was to phase Frodo's body into some sort of shadow-realm, not literally make him invisible. That's why his vision got all trippy and the Wraiths looked different; being invisible wouldn't do either of those things.

Aelfyre wrote:Another point I haven't seen mentioned unless I missed it.. if you are invisible a.k.a. 100% transparent with no refraction to light a.k.a. electromagnetic radiation you might almost immediately freeze solid since your body would no longer absorb any IR light or Thermal Energy and would bleed everything away fairly quickly I am thinking.

hmm that's actually another point in order to be truly "invisible" in addition to dealing with reflected/refracted external light you would need to somehow contain all the IR you normally radiate.

There's no reason to be invisible to the non-visible spectrum, though; since humans can only see in the visible spectrum, they won't see you to know to point IR goggles at you in the first place. So while they technically could see you with IR technology, they wouldn't. The only conceivable problem would be if a compound had IR-sensing cameras installed, which is unlikely.
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Re: Would you go blind if you became invisible?

Postby AvatarIII » Wed Jul 06, 2011 9:29 am UTC

King Author wrote:Having never read the books, I just assumed what the One Ring actually did was to phase Frodo's body into some sort of shadow-realm, not literally make him invisible. That's why his vision got all trippy and the Wraiths looked different; being invisible wouldn't do either of those things.


i always assumed the same thing, besides it's magic and therefore doesn't have to make sense.

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Re: Would you go blind if you became invisible?

Postby torontoraptor » Wed Jul 06, 2011 4:17 pm UTC

King Author wrote:Having never read the books, I just assumed what the One Ring actually did was to phase Frodo's body into some sort of shadow-realm, not literally make him invisible. That's why his vision got all trippy and the Wraiths looked different; being invisible wouldn't do either of those things.


Yah, I'm pretty sure that's the general accepted explanation. According to the books, Frodo was in the same 'realm' as the wraiths and elves, which made everyone else very difficult to see.
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Re: Would you go blind if you became invisible?

Postby POMPEYEAGLE » Wed Jul 06, 2011 5:01 pm UTC

No, it's not technological camo, it's magical camo. And if we're not allowing magic *or* technology, then the question is pointless to begin with, because invisibility is impossible.
If materials technology can pass light around you (with say a cloak) and reconstitute it behind you as if you were not there 'invisibility' is certainly possible. The problem is in the materials technology to do this and not the concept.

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Re: Would you go blind if you became invisible?

Postby Dopefish » Wed Jul 06, 2011 5:31 pm UTC

I wonder if you could spin up an explanation of invisibility in which it's not a matter of light passing through you, but rather the magic influencing other peoples eyes/brains to stop them from perceiving you. That way there's no personal blindness issues since you're still reflecting/absorbing light as normal, plus it means that the invisible person can still see themselves which seems to be the case in a number of invisibility depictions.

Cleaning up the details of the magic so others can see what they would if they could see through you and making the magic selective to just you as the invisible entity and not other identically coloured things might take some hand waving, but eh.

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Re: Would you go blind if you became invisible?

Postby gmalivuk » Wed Jul 06, 2011 5:57 pm UTC

POMPEYEAGLE wrote:If materials technology can pass light around you (with say a cloak) and reconstitute it behind you as if you were not there 'invisibility' is certainly possible.
No, because you'd still have to absorb some light to be able to see.
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Re: Would you go blind if you became invisible?

Postby Pella86 » Wed Jul 06, 2011 6:01 pm UTC

Dopefish wrote:I wonder if you could spin up an explanation of invisibility in which it's not a matter of light passing through you, but rather the magic influencing other peoples eyes/brains to stop them from perceiving you. That way there's no personal blindness issues since you're still reflecting/absorbing light as normal, plus it means that the invisible person can still see themselves which seems to be the case in a number of invisibility depictions.
...


this is from the Golden Compass ;) The witches in the book use this trick... reaching a interior energy something like meditation.. ;)

btw the infrared thing of predator makes sense to me too, you could deflect all the photons with a determined wave lenght, and absorb the other one, or orient yourself with ecolocation, but yes I think that you have to absorb light to see it... or an other really complicated way, would be to absorb the photon, and re-emit an other photon with the same direction/wavelenght after you "read/absorbed" it

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Re: Would you go blind if you became invisible?

Postby EricH » Wed Jul 06, 2011 7:03 pm UTC

gmalivuk wrote:No, it's not technological camo, it's magical camo. And if we're not allowing magic *or* technology, then the question is pointless to begin with, because invisibility is impossible.
I thought the OP was asking "what if the widget made you transparent, vs. bending light around you?" And I freely admit, maybe I didn't understand the question--but if I'm paraphrasing it correctly, it appears that capturing the incoming light pattern and retransmitting a copy from your other side is the kind of mechanism we were asked to exclude, regardless of the handwaving basis for it.
Unless the 'magic' part is that somehow you generate knowledge of the state of the universe without measuring anything.
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Re: Would you go blind if you became invisible?

Postby gmalivuk » Wed Jul 06, 2011 8:51 pm UTC

EricH wrote:I'm paraphrasing it correctly, it appears that capturing the incoming light pattern and retransmitting a copy from your other side is the kind of mechanism we were asked to exclude, regardless of the handwaving basis for it.
The point is that it still doesn't matter. Technological or magical, true and complete invisibility would make you blind, whether light is passing through or around the "invisible" object.
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Re: Would you go blind if you became invisible?

Postby Soralin » Wed Jul 06, 2011 10:22 pm UTC

gmalivuk wrote:
EricH wrote:I'm paraphrasing it correctly, it appears that capturing the incoming light pattern and retransmitting a copy from your other side is the kind of mechanism we were asked to exclude, regardless of the handwaving basis for it.
The point is that it still doesn't matter. Technological or magical, true and complete invisibility would make you blind, whether light is passing through or around the "invisible" object.

Well the idea is, that you make a copy of the light headed toward your eyes. One copy goes on to be absorbed by your eyes, the other copy gets bent around or retransmitted out the back of your head. And the light that would normally hit the back of your head still gets bent around or retransmitted from out in front of your eyes.

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Re: Would you go blind if you became invisible?

Postby gmalivuk » Wed Jul 06, 2011 11:19 pm UTC

And the receivers that make the copy in the first place: what happens to the light that should be going *through* those to make it look like nothing's there?
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Re: Would you go blind if you became invisible?

Postby Soralin » Thu Jul 07, 2011 4:07 am UTC

gmalivuk wrote:And the receivers that make the copy in the first place: what happens to the light that should be going *through* those to make it look like nothing's there?

It's absorbed, and a copy of it is transmitted going backwards, off of the back of your head, and vice-versa, the receivers transmit light going forward that would have hit the back of your head (where another receiver/transmitter is). Imagine that you have a full body suit that is both a camera and a video display at every point on it's surface. You could just record the light that hits one side of you, and transmit it out on the other side going the same direction, and you have invisibility. All you have to do from there is have a display which is in front of your eyes, but under your camera/video suit, to which a copy of the image striking the front of you is sent.

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Re: Would you go blind if you became invisible?

Postby Izawwlgood » Thu Jul 07, 2011 4:19 am UTC

Wouldn't the transmitters have to be omnidirectional? Or at least cover with sufficient resolution every possible angle the receiver could be viewed?
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Re: Would you go blind if you became invisible?

Postby gmalivuk » Thu Jul 07, 2011 5:00 am UTC

Soralin wrote:Imagine that you have a full body suit that is both a camera and a video display at every point on it's surface.
Yeah, and what I'm saying is that can't work.
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Re: Would you go blind if you became invisible?

Postby AvatarIII » Thu Jul 07, 2011 8:16 am UTC

gmalivuk wrote:
Soralin wrote:Imagine that you have a full body suit that is both a camera and a video display at every point on it's surface.
Yeah, and what I'm saying is that can't work.


well not with any technologies we have now, but i think that a suffiently advanced technology with both omnidirectional sensors and omnidirectional displays, and suffiently high processor power to calculate what images should be displayed where in real time, it could work.

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Re: Would you go blind if you became invisible?

Postby Dopefish » Thu Jul 07, 2011 12:16 pm UTC

I was going to complain that such a system would need to break relativity, but I suppose it wouldn't actually need to be instantaneous between absorption and remission.

Without actually doing any calculations, you probably wouldn't even need the relevant signals to even be all that close to travelling at c either to be functionally invisible to even the keenest (human) observer either...

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Re: Would you go blind if you became invisible?

Postby Izawwlgood » Thu Jul 07, 2011 1:07 pm UTC

I think the issue is viewing a transmitter at an oblique angle.
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Re: Would you go blind if you became invisible?

Postby Technical Ben » Thu Jul 07, 2011 5:03 pm UTC

gmalivuk wrote:
EricH wrote:I'm paraphrasing it correctly, it appears that capturing the incoming light pattern and retransmitting a copy from your other side is the kind of mechanism we were asked to exclude, regardless of the handwaving basis for it.
The point is that it still doesn't matter. Technological or magical, true and complete invisibility would make you blind, whether light is passing through or around the "invisible" object.


You could cheat. Use an external vision system (CCTV) and transmit the images via a different radio wavelength, or a totally different manner.

[edit]
Oh, and they are working on multiple angle viewable pixels too. Yep, it's highly improbably, but there is a possibility the technology reaches a certain resolution, or speed or brightness to give some sort of camouflage.
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Re: Would you go blind if you became invisible?

Postby EricH » Thu Jul 07, 2011 6:06 pm UTC

gmalivuk wrote:
EricH wrote:I'm paraphrasing it correctly, it appears that capturing the incoming light pattern and retransmitting a copy from your other side is the kind of mechanism we were asked to exclude, regardless of the handwaving basis for it.
The point is that it still doesn't matter. Technological or magical, true and complete invisibility would make you blind, whether light is passing through or around the "invisible" object.
Ah, now I feel better--for a little while, there, I was afraid we were disagreeing.
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Re: Would you go blind if you became invisible?

Postby Jakell » Fri Jul 08, 2011 1:30 am UTC

King Author wrote:
Izawwwlgood wrote:I remember reading something about how certain species of shrimp or deep sea fish (or maybe insects? this is spiraling towards 'I may not have a clue what I'm talking about') utilize eye stalks to keep their pigmented, visible eyes, separate from their largely transparent bodies.

The only deep sea shrimp with special eyes I know is the Mantis Shrimp, which can pretty much see the entire electromagnetic spectrum, and it has its eyes on stalks, but I don't think its body is transparent.

Not quite; the Mantis Shrimp sees a slightly larger slice of the EM spectrum then we do, certainly not the entire spectrum. Their eyes only extend a little ways into the near IR and UV.

Dopefish wrote:I wonder if you could spin up an explanation of invisibility in which it's not a matter of light passing through you, but rather the magic influencing other peoples eyes/brains to stop them from perceiving you. That way there's no personal blindness issues since you're still reflecting/absorbing light as normal, plus it means that the invisible person can still see themselves which seems to be the case in a number of invisibility depictions.

Cleaning up the details of the magic so others can see what they would if they could see through you and making the magic selective to just you as the invisible entity and not other identically coloured things might take some hand waving, but eh.

You mean something like the S.E.P. Field?

Now, if your invisibility cloak were able to replicate a small fraction of the the incoming photons, remaking those photons with directionality and all maintained on the opposite side, then you might be able to see some incoming light, as long as your cloak was able to make up for whatever you absorbed, kind of like what James Bond's vehicle was trying to do in Die Another Day. Lots of magic, there, since I can not imagine how the car could take into account every possible viewer's perspective.
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Re: Would you go blind if you became invisible?

Postby Sockmonkey » Sat Jul 09, 2011 5:30 pm UTC

Xanthir wrote:If you were transparent to *all* electromagnetic radiation, then yeah, you wouldn't be able to absorb radiant heat from the environment. You could still pick up heat from objects and the air via conduction.

You definitely wouldn't "almost immediately freeze solid", though. You'd lose heat slower than you would in a vacuum (again, because conduction is still warming you at least somewhat), and vacuum takes some time to freeze you. Meat holds quite a bit of heat, after all; plus, until you die of hypothermia, your body is still producing heat.

In Earth's atmosphere at ground level heat conducts into you way faster than it can radiate away. You wouldn't feel anything odd.
King Author wrote:
EricH wrote:On the topic of reflection, another bit of optical biology: some animals, like cats, do have reflective cells as part of their vision system--because the light-sensitive cells aren't completely opaque, some light does get through them. The reflective layer of cells sits behind the layer of rods, and bounces the extra light back through them, which gives the rods a second chance to absorb the light. This is why cats have very good night vision, and why their eyes shine--if you're holding a candle in the dark, and a cat looks at you, its eyes work like two tiny mirrors. But, if those cells became invisible, instead of reflective, the cat could still see, it would just need more light to do so.

Do you think surgery to give humans cat-like eyes would ever be possible? 'Cause I really want cats eye vision.
IIRC they did this is that movie with Vin Deisel. It was handled realistically in that he had to wear sunglasses in normal daylight since humans don't have cat pupils that can squeeze down to a tiny slit. It's probably doable with micosurgery but you would have to be way precise in injecting the reflective substance.

If whatever you're hiding from has IR goggles, no invisibility will work since a living body radiates heat and those pesky laws of themodynamics are real sticklers.
Granted you could wear a tank of liquid nitrogen on your back to cool the outside of your insulated invisibility suit but that's heavy and won't last long. Also, you could still be picked up on sonar.

Hmm, I want me some sonar goggles. Do they make them?


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