If this is the wrong place to be posting this, feel free to lock this thread. I wasn't sure if this belonged in "classical physics" or "quantum physics"; this seemed like the appropriate place, but I'm not 100% certain, as it does involve subatomic particles. Anyways, to get to the matter at hand. Suppose I had a machine that could detect the wavelength of a photon. If this machine moved directly toward a photon with a wavelength of one Plank length ( so that the photon and the machine would collide perpendicularly), what wavelength would the machine register? Would it register a wavelength of less than one Plank length? If so, does this have any implications for the validity of String Theory? If not, why?