Originally Posted by Idigmygirls

I feel compelled to respond only because I am a theoretical physicist (though I don't do a whole lot of that at the moment)...

A shadow is not an actual thing. It is the absence of light. More specifically, it is the area of a surface that is obstructed by an object that exists between it and a light source.

Understanding that, you should be able to see why your premise is incorrect. The light source generates photons that travel at the velocity of light. When a shadow is "cast" it means that some of the photons are blocked, while others are not blocked.