It’s true, the lines of longitude converge at the icy ends of the Earth, but time zones don’t always follow those lines — at the poles, or anywhere else. Out in the open ocean, it’s fine to use them to separate time zones, but what happens when a line splits a city in half? Do kids on one side of the city start and finish school earlier than kids on the other side? As fun as that might be, that’s not how it works — time zones wiggle around cities and countries, following borders more often than the actual lines themselves.

If you used the longitudinal lines to mark time zones at the poles, you could technically walk a small circle and pass an entire day! To get around this chronological conundrum, researchers and travelers who spend time in the high Arctic or in Antarctica follow the time zones of other places, usually their home countries or the country they communicate with most — in Antarctica, that’s mostly New Zealand. For scientific purposes any notation of time is always recorded in coordinated universal time (UTC).