This has nothing to do with language, but this weekend, the world commemorates the 40th aniversary of the first moon landing.
In the US, it is celebrated as 20 July. This is correct (in UTC) for the landing, but I remember clearly staying up until three in the morning of 21 July to watch Neil Armstrong make his giant step live on television in the UK.
When things happen on Earth, the date and time when they happen can be decided by the longitude of the event, so that Columbus reached the Americas some five hours earlier than the simultaneous time in Europe. Captain Cook sighted Australia some hours later than the time would have been in Europe, and possibly a day later than it was at that moment in America. Each New Year creeps up on Earth gradually over the space of a whole day.
But when an event happens elsewhere in the universe, whose terrestrial time zone is the one to use? While 20 July is correct for the Americas, much of the populated world will have watched the moon landing on 21 July local time – Europe, Asia, Africa, Australasia.