How can light interact with particles if it has no charge or mass? Does its momentum mean this is possible?

Question: How can light interact with particles if it has no charge or mass? Does its momentum mean this is possible?
- Keywords:
  interact,
  light,
  mass,
  momentum,
  particle,
  space,
  sub-atomic
Asked by sebstrug to Ben, Clare, Ezzy, Mario, Sam on 14 Mar 2012.
- Sam Vinko answered on 14 Mar 2012:
  
  The basic point to understand is that light is the mediator of the electro-magnetic force: its the way by which particles with charge interact. In quantum field theory you’d say that what you mean by ‘interaction’ of 2 charged particles is that they exchange a single particle of light (a photon).
- Clare Burrage answered on 14 Mar 2012:
  
  Light is what transmits the electric and magnetic forces. So for example when you hold two poles of a magnet close to each other so that you feel a force the two poles are transmitting particles of light from one to another. It’s just that this light is not in the optical part of the spectrum so you can’t see it.
  
  This means that any particle that has a charge will be interacting with light all the time, because it is using the light to say to all the other particles around it “I have a charge!”
- Mario Campanelli answered on 14 Mar 2012:
  
  the fact that the sun is warming you shows that light does interact with your body!

sebstrug commented on 14 Mar 2012:

Thank you for your replies, that was very interesting

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Question: How can light interact with particles if it has no charge or mass? Does its momentum mean this is possible?