By this logic, my oldest possessions are my protons, which are approximately the same age as the universe.
You would have to expound. I understand that protons are identical to each other, but I’ve never heard that they’re somehow all one particle.
That was a theory I read years ago. The idea is, that there is only one photon which exists more or less outside of time and so is everywhere a Proton would be expected.
Edit: was actually about electrons
https://en.m.wikipedia.org/wiki/One-electron_universe
The one-electron universe postulate, proposed by theoretical physicist John Wheeler in a telephone call to Richard Feynman in the spring of 1940, is the hypothesis that all electrons and positrons are actually manifestations of a single entity moving backwards and forwards in time.