I read that a photon is said to have zero mass at zero velocity.
Does this mean that they only exist in a state of probability until observed && interacting with some system? And then when observed they collapse into a particle that has velocity and said mass?
Or is it possible to have a photon behaving as a particle without mass?
This feels intuitively like the "wrong question", but could someone please explain to me how a photon, if it is energy, has no mass?
Are there any naturally occurring examples of photons without mass?