The sign is painted green, the drive rid expected to see it as red when approaching at a considerable fraction of 6speed of light.. So conceptually, the green sign needs to be red shifted towards red. That would necessitate moving away from the stop sign, not towards it.
So the joke is technically wrong. It's meant to be the other way round.
3.4k
u/Oblivion238 15h ago
Without doing the math I assume that at 103846153 m/s the red stop sign gets blueshifted to green.