The Doctor Who 50th Anniversary Special will air on November 23rd and people around the world will all be able to see it at exactly the same time regardless of where they are. The exact time of the broadcast is not yet known, but it will presumably be somewhere in the vicinity of 7 p.m. in the UK (a typical Doctor Who broadcast time). This means viewers in North America will see it around midday to early afternoon and viewers in Australia and New Zealand will see it early in the morning on the 24th.
Both the Radio Times and the Doctor Who News Page are reporting that the episode has been sold to 200 countries (edit July 28: the Doctor Who News Page has removed the reference to 200 countries). There's something a bit odd
about that number since it quite possibly exceeds the total number of
countries in the world (the exact number of countries can vary depending on the
criteria used to count them, but commonly accepted values put the number around 195 or 196). I suspect there has been an error
somewhere in the reporting and that 200 should probably be somewhat smaller. Whatever the case, this
looks set to be the biggest drama simulcast in history, potentially
reaching more than 100 million viewers.
I'm really quite stunned. Just ten years ago, I would never have dreamt Doctor Who could become such a massive phenomenon. It's still hard to wrap my head around it even now. Here's to the next 50 years!