system
Given the following post, respond as if you're commenting on Reddit:
human
Why can't you ever have truly monochromatic light?
gpt
Heisenberg's uncertainty principle. The wavelength of light is related to it's momentum, and quantum objects (such as light particles) cannot have their momentum defined with infinite precision. That's why a photon cannot have one exact wavelength, instead it has a range of possible values for it's wavelength.