How can someone achieve invisibility?

[nomorevishnu]

How can one be invisible??

I am working on a science fiction.I am sorry to open such a thread in the general physics section but i thought I could get the maximum possible logic from this section.Its about making someone invisible.What are the faintest possible ways to do that??Please give me some suggestions.
Thank you!

 

[arildno]

By stealing Harry Potter's invisibility cloak.

 

[Pengwuino]

A highly complex video and optical system and powerful computer with some neato fabrics.

http://science.howstuffworks.com/invisibility-cloak.htm

 

[Vixus]

A science fiction story? Go wild! We don't read SF novels to see how plausible something would be.

 

[Pengwuino]

A science fiction story? Go wild! We don't read SF novels to see how plausible something would be.

At least most of us...

 

[-Job-]

You could use a special suit where, for each photon that hits it on one area it emits a similar photon in the opposite area according to the angle of incidence. So suppose that a photon hits your shoulder at a 45 degree angle, then it would calculate where that photon would come out if it continued in a straight path and generate a similar photon in that very area. This would give the impression that light was going through the person wearing the suit. If you work it well you can make it quite believable unlike the classic novel "The Invisible Man" where the main character becomes invisible by noting that most cells in the human body are invisible, or transparent and then "bleaching" the features of the body that are not, like the blood, the hair, the nails, etc. Not a very good argument , not a bad read though.

 

[arildno]

I like fantasy better than sci-fi; I'll stick to magical solutions to this problem.

 

[-Job-]

Even though I'm not a huge fan of sci-fi, it tends to be a little over the top, I'm not at all a fan of fantasy. My favorite genre is general fiction. If it's something that's too unbelievable then i can't enjoy it, i can't lie to myself.

 

[Renge Ishyo]

To make something truly invisible you would need the light approaching the something from behind to exit the something in the front in exactly the same way (no obvious absorption, no deflection). At present there is no way to accomplish this, but for the hell of it imagine a full body suit with it's own oxygen supply that had a super computer, and its own power supply in it. The incident light at one angle is ideally fully absorbed in the suit and the suit takes ALL (360 degrees) of the incident light in, and without any delay, can translate the light signals and reemit light from the suit on the opposite side in real time in all possible directions.

The problem (among many, but I see this as the main road block) is that light travels at the fastest speed known. It might be possible, for example, to design such a suit that transmitted sound waves "through" the body without percievably deflecting them (because sound moves at 340 m/s at typical temperatures), but light moving at 3x10^8 m/s? No super computer in the world at present could process light signals and reemit them at a speed comparable to the speed of light with no significant delay (maybe you wouldn't need to go that fast in order to trick the human senses, but at the same time any flaw in the suit would reveal your presence and so you probably wouldn't appear completely invisible).

 

[Danger]

There's one thing about it that has always bothered me. I mentioned it several months ago in a similar thread, but there was no response. Some feedback would be appreciated. I seem to be the only person on the planet who thinks that an invisible person would be blind. If your retinae are invisible, light can't interact with them, and therefore there would be no visual stimuli.

 

[-Job-]

A truly invisble person wouldn't be able to see. However a visible person wearing an invisibility device (sounds pretty outrageous) could be able to see. There's a number of ways i can think so that this would be "possible". Of all the challenges that's not the hardest one to overcome.

 

[Danger]

Yeah, I agree that a device of some sort would allow vision. It's the mutated, or chemically altered, or whatever type of SF character that I'm referring to. eg: Sue Storm from Fantatstic 4, DC Comics' The Invisible Kid, etc..

 

[nomorevishnu]

Well.Danger,I know that an invisible person can't see.Because his retina wouldn't be able to reflect the rays.But is it possible in a way that some sort of genitical implantation is done and in such a way that the person can actually see everything.I am not talking about any kinda wonder drug.But something that can be implanted inside the human body rather than outside(just like the invisibility cloaks u all have been talking about.I don't want those).
Any ideas on these lines??It would be really great if some of you could still contribute to this thread!

 

[starfield]

Switch Of The Light! Ha!ha!

 

[zoobyshoe]

I think the best way to become invisible is to affect the mind of anyone in the vicinity such that they cannot focus their attention on you. In a sci-fi novel this could be accomplished by having the "invisible" person wearing some device that affects the "attention" circuits of the brains of anyone looking in his direction. You might propose that device to be ultrasonic or electromagnetic. It might be a kind of helmet with omnidirectional sensors that are specifically dedicated to recognise when two eyes are focused in it's direction, whereupon it sends the jamming signal back to this target.

I've often had the experience of not being able to see something that is pretty much in plain sight, and I think this is due to some temporary inability to process a "recognition" of it. It's occurred to me once or twice that there might be a way to induce this in other people. I've read claims it can be done with hypnosis, but that wouldn't be practical for someone who wanted to walk around invisible to any and all he encountered. It probably can't be done with any device, either, but that's not a problem in science fiction.

 

[nazgjunk]

I think the best way to become invisible is to affect the mind of anyone in the vicinity such that they cannot focus their attention on you.

Could it be that you have read "The Hitch Hiker's Guide To The Galaxy" a bit too often? This reminds me very strongly of a SEP, a "somebody else's problem". It sounds sort of impossible to me though, especially when hidng something as big as a human being. After all, humans are "large stupid folk like you and me [who] come blustering along, making a noise like elephants which [hobbits] can hear a mile off", as J.R.R. Tolkien put it so nicely. We affect everything near, such as sand an the table you just bumped into. It would be very hard to hide that too.

 

[zoobyshoe]

Could it be that you have read "The Hitch Hiker's Guide To The Galaxy" a bit too often?

I've never read it.

This reminds me very strongly of a SEP, a "somebody else's problem". It sounds sort of impossible to me though, especially when hidng something as big as a human being.

If you're unable to focus your attention on something it's size is irrelevant. The basic notion is as firmly grounded in neurology as the other ideas are in physics. There are dedicated circuits in the brain for recognition and they do break down in specific kinds of brain damage such that people can no longer recognise faces or words or sounds. This is called agnosia. There is a very famous book called The Man Who Mistook His Wife For A Hat which is a collection of case studies of people with various neurological disorders. The title story is about a man who has become unable to recognise the physical appearance of anything despite the fact there is nothing the matter with the physical apparatus of his eyes. The problem is in his brain where the visual information is processed.

After all, humans are "large stupid folk like you and me [who] come blustering along, making a noise like elephants which [hobbits] can hear a mile off", as J.R.R. Tolkien put it so nicely. We affect everything near, such as sand an the table you just bumped into. It would be very hard to hide that too.

I'm not sure why you pick my suggestion out to mention this because all the suggestions have the very same limitation. An invisibility suit isn't going to cover the sounds you make.

 

[arildno]

Great idea, zoobyshoe, however that's just what the spirit magic spell "Invisibility" (3p, active) does in RuneQuest, 3rd edition.

 

[Danger]

Zoob's idea was the basis for 'The Shadow' back in the 30's (or thereabouts)... 'the ability to cloud men's minds'. Unfortunately, that was before the advent of security cameras.
Sound will always be a problem, as will infrared signatures. Since those are radiated phenomena rather than reflected, your 'suit' or whatever would have to retain heat. I have no idea how you can mask the sounds that you make, unless you just move very carefully.

 

[ukmicky]

This may be a bit futuristic but is this feasible

How about if the skin/surface of the thing that you wish to cloak is made from millions of microscopic optical fibres that are feed the light/image of the opposite side.

In the end all they have to do is reproduce colour. so if there were two types of fibres all mixed together and half of the fibres were sending the surrounding image of their side to the opposite side, and the other half were receiving the surrounding image from the other side it would be like a chameleon

would it work

 

[nazgjunk]

Uhm, but you still need to position those fibres somehow... fibres have thickness...

/me is NOT contructive, no.

 

[Mk]

This may be a bit futuristic but is this feasible
How about if the skin/surface of the thing that you wish to cloak is made from millions of microscopic optical fibres that are feed the light/image of the opposite side.
In the end all they have to do is reproduce colour. so if there were two types of fibres all mixed together and half of the fibres were sending the surrounding image of their side to the opposite side, and the other half were receiving the surrounding image from the other side it would be like a chameleon
would it work

I'm sorry sir, but post 6, and post 3 already offered that explanation. Nice idea though.

 

[Mr.Socrates]

let us go to the micro level and even to the atomic level... the atoms are invisible and so are the molecules ...let us assume it is due to size ... then what is transparency and why does some appear translucent and some appear opaque ... I think there lies ur answer for ur quiery

 

[zoobyshoe]

Great idea, zoobyshoe, however that's just what the spirit magic spell "Invisibility" (3p, active) does in RuneQuest, 3rd edition.

What's "RuneQuest"? A videogame? If it's a magic spell it's already something different than science fiction.

Zoob's idea was the basis for 'The Shadow' back in the 30's (or thereabouts)... 'the ability to cloud men's minds'.

I'm not familiar with it, but I'm going to guess this is some kind of superhero power he had, and not the same kind of thing I suggested. I took the OP to be asking for a scientifically plausible means of becoming invisible for science fiction purposes.

The X-Files had at least two characters who escaped detection by ninja-like force of will. One, they speculated, was manipulating the viewer to look at him such that he was always placed in the blind spot. That was kind of ludicrous since we only have a blind spot in one eye. The other "disappeared" by "willing" the others to see him as someone else. This character had the ability to affect video tape the same way: he could impress the alternate appearance on security camera footage. All not science fiction, but essentially magic.

My suggestion was not a magic spell or "force of will" sort of thing at all.

 

[arildno]

RuneQuest is the best role-playing game in the world, devised by Chaosium Inc., and then mistreated by Avalon Hill.

 

[Danger]

Zoob! How could you not be aware of 'The Shadow'. It was a huge pulp magazine and radio series, and there was even a movie remake in '94 with Alec Baldwin in the lead. See http://www.spaceports.com/~deshadow/" for a brief account.
Anyhow, I wasn't proposing it as a plausible approach; just pointing out the similarity.
I suppose you could take the approach of 'The Flash' or 'Superman'. If you don't mind burning to a crisp or dying of old age in a few hours, you could accelerate your molecular motion to the point where the eye can't follow you. Of course, you'd also have to eat constantly and carry a high-flow oxygen system (which would explode, incidentally).

 

[zoobyshoe]

Zoob! How could you not be aware of 'The Shadow'.

I'm aware of it, just not familiar with it: never seen it and don't know any details.

 

[Livingod]

Hey, I may be a little late into the discussion, and I haven't read all the posts, but I have a suggestion. This invisibility cloak could have these properties:

1) light will come to one side of the cloak, be converted into some form of energy, say 'A' energy, go straight through the user, and be reconverted to light as it passes through the cloak on its way out.

2) no light from the inside of the cloak will escape.

3) No 'A' energy from outside the cloak will enter the cloak

4) this cloak is not reversible, as the two sides have different properties

5) light will be allowed to enter the cloak along with its 'A' energy counterpart, so that the user can see what is outside

6) 'A' energy will be allowed to exit the cloak along with its light counterpart, so that if overlapping of the cloak occurs, there will be no black spots

Major setbacks:

1) we need to find a type of energy that won't harm the human body AND pass through it.

2) we need to find material to convert light to this energy type and back again.

and one problem, the user will look like a black body when viewed from above, since the bottom is open and thus, there is no 'A' energy coming from the bottom, so the top will emit no light upwards.

This problem can be solved with an invisibility suit, which has 360-degree coverage, including shoes.

 

[zoobyshoe]

I suppose you could take the approach of 'The Flash' or 'Superman'. If you don't mind burning to a crisp or dying of old age in a few hours, you could accelerate your molecular motion to the point where the eye can't follow you. Of course, you'd also have to eat constantly and carry a high-flow oxygen system (which would explode, incidentally).

This is a problem that never occurred to me in connection with various shows that have the premise of a person speeding themself up beyond other's ability to see them. (The original Star Trek used this once). I wonder if we figured out the slowest speed a person could go and still be faster than the mind's ability to process the information if it would be fast enough to cause burning by friction with the air. The brain "samples" the visual field at about 15 times a second, from what I've read. How much those samples have to overlap to form an image I'm not sure about. I do know that we go completely blind briefly all the time when we're are shifting our field of vision. During the split second in which you shift from the end of one line of this text to the beginning of the next, for instance, you are blind.

I just though of another possible problem, which is that, even if you didn't burn up, there's a good chance you'd be supersonic and creating sonic booms by just walking down the street.

 

[Danger]

There's also the question of how much horsepower a dude would have to generate to get his mass moving. All of those speedsters in the comics and movies seem to have almost instantaneous acceleration.
There's one statement you made that should be clarified in case someone takes it the wrong way. Both eyes have blind spots, but they don't coincide.

 

[nazgjunk]

There's also the question of how much horsepower a dude would have to generate to get his mass moving. All of those speedsters in the comics and movies seem to have almost instantaneous acceleration.
There's one statement you made that should be clarified in case someone takes it the wrong way. Both eyes have blind spots, but they don't coincide.

They are comics, please. Ever saw the full DragonBall Z series? It is as unrealistic as hell, but those guys go fast, without aging. OF COURSE it's not realistic.

 

[Danger]

I'm quite aware of that, nazgjunk; therein lies the difference between fantasy and science fiction. What we're trying to do here (even though it got off topic), is find an invisibility device that doesn't violate physical laws. A discussion of various approaches is appropriate.

 

[nomorevishnu]

Kool...I am overwhelmed with the kinda response i have got.But inmy second post I had asked for some technique that would allow a person to intake something and then be invisible.I mean nothing external.Like a drug or injection or anything of those sorts.Immediately my mind can't think of anything in those lines that provides logic...but some vague ideas?I m looking forward to it!
Thanx

 

[Danger]

Okay, Nomore... something just whapped me upside the brain here, but I'm going way outside the box. You never specified if this character has to be human.
If not, what about maybe a silicon-based lifeform that can control its index of refraction?

 

[nomorevishnu]

Oh it is ofcourse human...Thats where the fun always is...
So Mr.Funniest Member...hope something better whaps up...u or me...
Something that can make a human go invisible ok guys?
And it should be internal...not a cloak...Please...i will ofcourse post my idea if something strikes me!

 

[Renge Ishyo]

.But inmy second post I had asked for some technique that would allow a person to intake something and then be invisible.I mean nothing external.

Well, unfortunately humans are made of atoms that interact with light, so without a "work around" or some way to somehow change how atoms behave you are pretty much SOL.

Without the use of some suit or trick to create the illusion of invisibility, I can think of one "real world" way to make a human "invisible" and that is to heat the body until you liquify all the chemical compounds in it and then continue heating it until it enters the gas phase. At this point, it is possible that humans who walked into the room and tried to find this person would not be able to see their body in normal lighting conditions (because it will be in the form of a gas).

There are a couple err...shall we say, "drawbacks" with using this method to become invisible: 1) There is no way for you to control where your molecules are going to go while you are in the vapor state. So you could not mosey your little "cloud" to the front of the line in the DMV or into the girl's locker room, etc. purposefully, rather you would be at the mercy of the wind. 2) You would lose your life in the process as unravelling your molecule structure (while making you "invisible") would simultaneously make you...err, nonexistent (which is not what I think you had in mind).

Now you may be able to think science fiction wise about changing to the vapor state, sneaking past enemy lines or whatever, and then having a computer "reassemble" the molecules exactly as they were when they were done, but if you could go to that sort of trouble you might as well just build the damn suit and be done with it

 

[Danger]

I agree with Renge, Nomore. There is no physical/chemical treatment that can make a human invisible without killing him. If you insist upon making one up, make sure that you refer to your writing as 'fantasy' rather than 'science fiction'. To maintain any credibility, you're stuck with an external device of some sort.

 

[Mixolydian]

One way, I guess.. is just make a suit that obsorbs all light. You wouldn't apear invisible you would be completely black, like a shadow figure I guess it would only work well at night seeing as anyone would only be able to see someone outside in the dark with moon light but the suit would absorb that and you would just continue to look like a dark part of the side of the street or something. Doing it at day time would freak people out.. a random spot of darkness...

 

[langtu]

I still do not understand why a invisible person is blind. Although his or her retain can not reflect light,the light coming to his retain still damages his retain (for example, the light from the sun still burn a plastic or heat from sun still makes the water transfer to cloud although they are almost invisible). Thus, it still causes chemical changes in the photosensitive cells of the retina, the products of which trigger nerve impulses which travel to the brain, so s/he still see as a result.

 

[Mk]

But the cones and rods are invisible, meaning the light goes right through it, unaffecting.

 

[langtu]

I mean the light go throughout one thing does not mean it does not affect on that thing. In fact, the light from the sun heats us everyday although it goes through the air(invisible). Am I right with this example?

 

[vanesch]

I mean the light go throughout one thing does not mean it does not affect on that thing. In fact, the light from the sun heats us everyday although it goes through the air(invisible). Am I right with this example?

Actually, when light goes through something without undergoing any chance what so ever (phase, intensity, direction...), then no, the light cannot affect the thing either.

 

[alfredblase]

One way, I guess.. is just make a suit that obsorbs all light. You wouldn't apear invisible you would be completely black, like a shadow figure I guess it would only work well at night seeing as anyone would only be able to see someone outside in the dark with moon light but the suit would absorb that and you would just continue to look like a dark part of the side of the street or something. Doing it at day time would freak people out.. a random spot of darkness...

Mixolydian, that's the best idea I've read in this thread so far; it would certainly be extremely difficult to spot in the dark, but psychologically speaking, I wonder if the brain would be so freaked out by this moving black thing that it would ignore it even in dayilght

P,S that runequest game sounds like it would make a good computer game, has it been made into one yet?

 

[Gokul43201]

One way, I guess.. is just make a suit that obsorbs all light. ... Doing it at day time would freak people out.

Another reason not to wear this suit in the daytime : Assuming even a minimal solar intensity of 100W/sq.m (that's a cloudy winter day in Maine), and a super heavy suit with a giant heat capacity, it would warm up at a rate of about 6K/min. In less than 20 minutes you can boil water on your suit ! If this is noon-time in Singapore, make that 2 minutes.

 

[damitr]

Even building up an invisibility device, would make person invisible (if possible ) 'only' in some wavelength range.

The device MUST radiate at some wavelength or the other , which will be related to its temperature (BBR).

 

[pinestone]

...Its about making someone invisible.What are the faintest possible ways to do that??Please give me some suggestions.
Thank you!

Eliminate all the light. Nothing is visible in absolute darkness.

 

[-Job-]

Of course that would involve killing oneself.

 

[blimkie]

I love when science fiction novels are somewhat plausible and portray accurate physics, same with movies such as arthur C clarkes 2001: A space oydessy

 

[Chaos' lil bro Order]

NON-SUIT SOLUTION

Most color as we know it arises from the properties of molecules when their Carbon backbone structure has 'conjugated dienes'. This means in lay terms that there are Carbon atoms strung together with alternating single and double bonds (ie. -C=C-C=C-C=C- etc.). The molecule in Rods and Cones that allows us to 'see' light is also a conjugated diene, called 'cis-11-Retinal'. When a photon strikes 'cis-11-Retinal' it makes a conformational change (changes shape) into 'trans-11-Retinal' and essentially opens up a gate through which a tiny electrical current can now pass through and eventually reach the brain, where you perceive this signal as light.

However, 'cis-11-Retinal' is always imbedded in an even larger molecule which is called 'Rhodopsin'. Rhodopsin is a large globular protein (globular basically means spherical) which always has the same basic structure, but there are a variety of Rhodopsin proteins which all vary slightly with the addition of a few atoms here and a few atoms there. Its these small variations that make all the difference to you and I when we perceive the wide variety of colors that we can perceive. For only a specific type of Rhodopsin will allow incident (incoming) light to pass through it and strike the all-important 'cis-11-Retinal' whereupon whenceforth the electrical signal is passed onwards up to the brain.

That is why our 3 color sensing cones, namely the L-cone (Red), M-cone (Green) and S-cone (Blue) are only good at sensing the color of light that their specific 'Rhodopsin' protein let's through.



With all of this background in mind, consider this possible solution for biological invisibility without the need for a suit:

It is possible in theory that you could line your body with Rhodopsin proteins all along the epidermis of your skin and you could then use these proteins to detect all the incoming light around you from all directions (the INPUT part of the problem). Now we come to the more difficult problem of how to get the body to OUTPUT the colors of light we need to perfectly mimic the INPUT signals we have just received.

Generating the proper OUTPUT of colors all over your body surface would require each skin 'pixel' to be a maximum size of say 0.1 mm to ensure that no human eye could be visual acute enough (have good enough vision) to see that you are not invisible, even when their proximity to you is within a foot. Recalling that molecules emit color based on their 'conjugated diene' structure, it is forseeable that we could genetically engineer proteins that produce molecules of all the required colors for our OUTPUT. These proteins could be place locally in the epidermis where they would be interspersed in a mosaic beside our INPUT 'Rhodopsins' and then an INPUT 'Rhodopsin' situated 180 degrees (opposite side of the body) could send an electrical signal through a nervous system (a special nervous system suited to connect INPUTS and OUTPUTS) to tell the OUTPUT protein to generate a molecule that's color mimics the 180 degree INPUT.

This is my idea of how to create biologically induced invisibility. There are several little quarks that I can think of that would need to be smoothed out, for example since the body is not perfectly spherical, the INPUTS and OUTPUTS would not really be perfectly coupled by 180 degrees. Just think of a woman's breast and her back, clearly the INPUT 180 degrees from her breast would not correspond to the correct mimicry of her OUTPUT on her breast, since her breast is curved and her back flat. But I think that you can appreciate that this problem could be worked through by finding the proper INPUT/ OUTPUT mimicry angles needed for all of your body surfaces and its skin pixels.

Other than that, there are a handful of other hurdles to overcome, however I think the guts of my solution is pretty good.

What do you think?

 

[spiffing_abhijit]

A person should stand in front of a mirror and see his image.I would not be surprised that most of u will dislike my idea but it's my suggestion.A man should have and electronically controlled suit which exactly can match 100 per cent accurately with the colour of the existing environment.Also the suit should adjust with the changing light and the changing time and environment.Modern technology has found this invention quite comprehensively and this is not the present issue in front of the scientists working on science fiction.