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H. G. Wells' The Invisible Man

  1. Sep 13, 2003 #1
    This topic has interested me ever since I read H. G. Wells' The Invisible Man: How can you make someone truly invisible?

    Any ideas are welcome, as I have never thought of a scientifically (or even logically) feasible way.
    Last edited by a moderator: Feb 6, 2013
  2. jcsd
  3. Sep 13, 2003 #2
    Here's an idea...you have a suit with microscobic cells, some of these cells absorb light some are light sources, those which absorb the light give the information (colours, intesity, etc.) to other cells on the other side of this suit. So if you look at a person with this suit on you'll see what you would see if this person wasn't there.
    Naturally this is only theory and hardly practicle.
  4. Sep 13, 2003 #3


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    I had an idea like this a few years ago when I was thinking of writing a short story. In the story a peasant has rescued a witch (actually a representative of an advanced society) from the gallows and they have escaped into the nearby woods, but a search for them has been mounted. Now the witch removes her baggy dress which turns out to be just such a device as you mention, but at a slightly cruder level. She whispers to him that it wouldn'y fool anyone in the light of day, but in the woods, at dusk, it just might. They huddle under it deep in a copse of bushes and are overlooked.
  5. Sep 14, 2003 #4
    poke the other guys' eye out
  6. Sep 14, 2003 #5

    Yes, I thought of this, but I was hoping for something a little less violent :wink:.
  7. Sep 14, 2003 #6
    This is what I'm told the new 007 car is like (I haven't - and don't intend to - see(n) the movie). I suppose this is somewhat practical, except that there would have to be a computer that could calculate exactly what the environment would look like (if you weren't there, that is), and change the suit to fit that calculation every time you move. Otherwise, it does seem possible in principle.
  8. Sep 14, 2003 #7
    On a side note:

    They actually use cameras that feed what they see to projectors laced throughout the car that projects the image.

    Hey, it's a Bond movie. :wink:
  9. Sep 14, 2003 #8
    I see.
  10. Sep 15, 2003 #9


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    This approach has been explored by the US Army. The cells were not microscopic, but small octagons about 3-4 inches accross. These were the projection screens, and they fit together like the cells of a honeycomb. At the joints between the screens, there were pinhole cameras with fiberoptic lines running to the appropriate screen the one on the opposite side of the soldier's body).

    But, as you say, not practicle. Horrendously expensive to make and almost as bad to maintain, the suit only turns out to be a slight improvement on camo. The plates are large and flat enough to reflect sunlight sometimes, and produce only a fragmented image of the terrain behind the soldier. Maybe the microscopic cells you suggest would work better, but I'm not sure such tech even exists, and if it does, it would be even more expensive.

    Maybe in the near future, though.
  11. Sep 16, 2003 #10
    The only real practical invisibility camoflage for the forseeable future is for stealth aircraft and ships.

    The simpliest way to be invisible is just not to be there. The military already has fly sized video cameras, robotic snakes, and who-knows-what in the works. The next generation of aircraft will theoretically be mostly remote control whether invisible or not.
  12. Sep 16, 2003 #11
    An aircraft or ship invisible to the naked eye is worthless.
  13. Sep 16, 2003 #12
    What you don't see can hurt you.
  14. Sep 20, 2003 #13
    Really?.....maybe I should go and work for Q then:wink:
  15. Sep 20, 2003 #14
    Hmmm....or maybe I should go and workk for the US Army...
  16. Sep 20, 2003 #15
    There is no possible way to create complete invisibility that is also useful, although you could theoretically get awfully close. The problem is, if you are completely invisible, you cannot see!! If you allow light to pass around or through you, no light will reach your eyes. If you absord all light, you will appear black. And if you are simply projecting images for the illusion if invisibility, you will still have a heat signature which can be picked up.
  17. Sep 20, 2003 #16


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    Having given the millitary's approach further consideration, I notice a new possibility. Another project under developement for the millitary is the powered armor suit. It would be safe to assume that this suit, when developed, will be as stealthy as DARPA can make it. It will probably have features to decrease its heat and radar signature as much as possible. But the projection method of invisibility would also be made easier by the adbvent of such a combat vehicle. This suit would not require the flexibility of a camo uniform, and so the flat screens with flexible joints between them could be illiminated. The position of each part of the suit's surface is far more predictable, making projection easier and more realistic in appearence.
  18. Sep 22, 2003 #17
    Yes, I'd considered this, and that's why the "invisibility suit" wouldn't necessarily make you invisible, but rather make it so that all others can see is your surroundings. It would also help to have the typical "stealth" features (undetectability by radar and the like).
    Last edited: Sep 22, 2003
  19. Sep 25, 2003 #18


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    Here's a challenge: how do you know where to project images to (if it's just this kind of illusory invisibility you are after)?

    If you want to appear invisible to observers 'at infinity', a 'light pass-through' arrangement might work; if the observers are close, there's no way you can project images to all possible observers without some parallax problems arising for at least some observers (and if you don' t know where they are, you can't correct for this). Of course, that's not a problem if you're in a blizzard, but then a nice white camo kit would do the trick just as well.
  20. Sep 27, 2003 #19
    Check out Zero's post, he addresses the "light pass-through" possibility.

    But what if you had a small computer in each "projector", which calculated the distance between you and observers, and thus compensated for differences in PoV?
  21. Sep 27, 2003 #20


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    The computer would have to know the distance to all objects in the field of view (of the soldier), to even begin to eliminate parallax.

    Further, each 'projector' would need to emit through a full ~ 2[pi] steradians, across the whole of the visible spectrum (and into the IR, thank you Zero), with an angular resolution of no more than ~5 arcmin, a response time of <0.1s, and a dynamic range of >5 orders of magnitude.

    ... and we haven't started to specify the detectors.

    Hmm, not your average movie cinema projector; not your average PC.
    Last edited: Oct 2, 2003
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