From: mikkelhaaheim@gmail.com   
      
   On Thursday, February 16, 2017 at 4:32:22 PM UTC+1, Damien Valentine wrote:   
   > On Tuesday, January 24, 2017 at 5:45:00 AM UTC-5, ewu...@gmail.com wrote:   
   >   
   > > But, what if it was possible to detect a spot or point of light in just   
   air, without   
   > > the need of a surface for that spot/point to bounce of.   
   > > What would be the practical applications of such an invention.   
   >   
   > We already have those devices: they're called "digital cameras". (The   
   photons/waves don't bounce off anything -- they're focused by a lens, then   
   directly absorbed by a CCD and converted into electrical signals.)   
      
   I think you are misreading his admittedly imprecise question. I think, when he   
   refers to "bouncing off", he actually means "interacts with". In your example,   
   the light is interacting with the CCD.   
   In other words, I think he is asking what would happen if we could detect a   
   photon without interacting with that photon, either directly or indirectly.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)