XPost: sci.space.policy, sci.physics, sci.astro   
   From: tkoenig@netcologne.de   
      
   Doc O'Leary  schrieb:   
   > Another fine   
   > example is 3D TV or holograms.  Yes, there are people trying to get   
   > there, but they don’t exist in *any* sense as their science fiction   
   > promise.   
      
   Holograms is actually one of the worst cases.   
      
   It seems that very many SF authors simply do not understand   
   the properties of real holograms at all.   
      
   A hologram consists of an interference pattern.  When directed   
   light falls on that pattern, 3D objects can be seen.   
      
   One point that SF authors or directors routinely miss is that you   
   cannot see anything of the hologram if you are not looking at   
   the interference pattern.  A hologram cannot absorb, bend or   
   refract light anywhere else (so the Doctor from Voyager is out).   
      
   It is also not possible to have 3D projector that, simply by   
   projecting light, can make something appear in thin air that can   
   be viewed at an angle from the projector.  So, forget about R2D2   
   pojecting the picture of Princess Leia.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)