Ahh, so we're assuming eternal universe implies that the entire universe is in thermal equilibrium. This makes some sense, but it feels like cheating. Because t

Ahh, so we're assuming eternal universe implies that the entire universe is in thermal equilibrium. This makes some sense, but it feels like cheating. Because then the paradox is broader: "how can anything be at a different temperature to anything else in an eternally old universe?". Nothing really to do with night skies.