Hi. From what I've read about the "observer effect" in the two slit experiment, the electron's wave function collapses due to photons altering its momentum. Now, in the beginning of the universe photons couldn't escape the original Big Bang fog until it cleared out, so these should have interacted with "all" electrons in the early universe. Then how come electrons, or any other particle, behave as wave nowadays? Is there some mechanism in which electrons "expand" their wave again?