Mainly because of the reasons I just gave.

Also because even though stopped clocks are right twice a day, you shouldn’t use them for timekeeping — Fiction can be satire, or have a social message, or be hard science to give a narrative explanation to confusing-but-real physics, but it can also be Harry Potter, The Hobbit… or the wildly implausible specific events and timescales in The Day After Tomorrow: https://en.wikipedia.org/wiki/The_Day_After_Tomorrow#Politic...