I have a question to ask. I am pursuing a career in theoretical physics, most likely LQG and/or cosmology, but thus far my mathematical knowledge spans only newtonian physics. My question is in relation to the Heisenburgh uncertainty principle. Now I know that there are several factors other than position and velocity, but I of course have only read the popular texts and so I only understand the uncertainty principle in this context. That is, the more precise a position you want, the more energy you must invest and thus the more the velocity has been changed. And so on. I guess my two questions are this: 1. How is it possible for us to know that photons always travel at c? Why doesn't this violate the uncertainty principle? 2. How many properties of quanta are effected by the uncertainty principle and why? For example, spin does not change, correct? Niether should charge. (I am unfamilair with quantum numbers so try to be specific. How many properties do quanta have?) I guess that is more than two questions but they have bee bothering me.