The amount of length contraction is frame-dependent; it doesn't depend on the type of particle, it depends on the particle's velocity relative to the observer.If I am understanding you properly then I would assume that a neutrino (or maybe an electron) which has mass, would experience the most length contraction (similar to a muon in that scenario,) of all the particles that exist?
We have a FAQ on this:So explain the tie to the inertial frame for the photon to see length contaction.
Where is it "always stated"? What valid source (textbook or peer-reviewed paper) says this? Yes, pop science treatments might use this misleading language, but that just illustrates why you don't want to learn actual science from pop science treatments.why is it always stated...
Yes. I strongly advise you to take some time to work through an actual textbook on SR. Taylor & Wheeler's Spacetime Physics is one such.Or are these analogies of how a photon perceives the universe incorrect in some fundamental way?