999
xkcd #2867: DateTime
(imgs.xkcd.com)
Alt text:
It's not just time zones and leap seconds. SI seconds on Earth are slower because of relativity, so there are time standards for space stuff (TCB, TGC) that use faster SI seconds than UTC/Unix time. T2 - T1 = [God doesn't know and the Devil isn't telling.]
Y'know, I legitimately said to myself "I bet they were writing that from memory and just forgot the edge case. I wonder if that was a problem when doing it originally?" before I wrote that comment. ๐ Time to get some Spock tests set up!