i am curious to know how to scientifically achieve the lack of a shadow for a person. what would have to happen technology wise for a person not to cast a shadow in direct sunlight. i have only thought up a simple way of achieving this by having a light source on the back of the user that would sample the light in front of them and then project the same amount of light behind them drowning out their shadow and seamlessly blending with the light around them, could this work?

Edit: I am asking if

  1. My suggested method of attaining the lack of a shadow would work , and if not what would have to be done to make such a system be feasible

  2. Other ideas for technology to produce the lack of a shadow

  3. What would be the practical implications of such a device

4 if such a device could malfunction in a special circumstance such as different lighting or an optical illusion

Parameters : 1. The subject who's shadow is being hidden is a regular human made of flesh and blood

  1. The user is still visible nothing is different from any normal human besides a lack of a shadow in direct sunlight

  2. No magic only technology

  3. Gravity lensing is allowed


closed as unclear what you're asking by JDługosz, Hohmannfan, Aify, Separatrix, Burki Sep 21 '16 at 7:17

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  • 3
    $\begingroup$ Are you asking for yes/no, engineering ideas for such a device, alternatives to this one mechanism, or what? $\endgroup$ – JDługosz Sep 21 '16 at 5:08
  • $\begingroup$ The individual would have to be composed of a single crystal, or some other structure where there are no clearly defined grain boundaries, as these are the places which reflect light. The means you've suggested, a built in light source, will not work to prevent a shadow in bright sunlight, as you'd have to match the intensity of the light hitting you. $\endgroup$ – nzaman Sep 21 '16 at 12:34

A cloaking device does exactly this already. Just take the light you would have obstructed, direct it around you, and project it out the otherside with exactly the same trajectory as before. Little bit of lag, since it's traveling farther now, but not easy to notice.

  • $\begingroup$ The lag you described will be very very small since light travels at immense speeds and adding a few meters to its trajectory will probably not be visible by us. it would rather be a lag created by the technology manipulating the light $\endgroup$ – GijsM Sep 21 '16 at 6:21
  • $\begingroup$ I did say it wouldn't be easy to notice. But any good story about a cloaking device should consider ways of detecting a cloaking device. $\endgroup$ – candied_orange Sep 21 '16 at 7:03
  • $\begingroup$ Agreed, that's why i said that the lag would be on the technology manipulating the light and not the light itself since that would not be visible to us. The Predator movies for instance, the creature is almost invisible when standing still but when it moves, the cloaking device has some trouble and he becomes a bit visible. Just stating that the factor which creates the lag should be the device and not the light itself :) $\endgroup$ – GijsM Sep 21 '16 at 7:10

As already mentioned by CandiedOrange a cloaking device might do the trick. Another (possibly over the top) idea might be a multidimensional state (not sure what the official term is). You can compare it to a invisible ghost in movies who can move around and interact with stuff but actually it's a form of technology that puts the user in a different dimension and creates this ethereal or ghostly state but still allows the user to interact with everything in our dimension


The person could be a hologram. They might be projecting in from some other location.


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