For example. A star is 8B light years away, we’re told that that the light has taken 8B years to get to us.
BUT the universe is constantly expanding therefor was the star not much much closer to us therefor making it’s light younger?
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From whose perspective?
From a particular (pun intended) point of view yes and no. The photon could have been emitted billions of years ago and traveled across space to reach your eyes–from your perspective. From the photon’s perspective (an invalid reference frame) no time has passed since space has zero length in its direction of travel so it traveled instantly from where it was “born” to where it “died”–a photon has no sense of space or time travel.
From a wave perspective the electric and magnetic fields have been oscillating along the path of the wave for billions of year, but there isn’t a real “thing” there since the photon is merely fluctuation in the electromagnetic field. That said “real” particles are just fluctuations in different fields according to QM.
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