Dear Ernest, How can Santa get around the whole world in just one night? I don't get it. Earl T. Boston, USA

I remember you, Earl.

You like to ask the deep questions. Ever since you were a little kid, your letters to Santa have always delved into the mysteries. And ever since you took that position at MIT your questions have only increased.

But this one is really quite simple. And let me answer by asking you a question: when you eat lunch in Boston, what are your parents doing in San Francisco? At the same moment in time that you bite into your daily bologna, your Mom is clearing the breakfast dishes. It's the same moment in time for you both, but it's a different time altogether.

That having been said, what time zone is the North Pole in?

C'mon, genius. If you can answer that, then you can answer how Santa does it all in just one night. If you think about it, it's not that difficult to accomplish after all.

Now let me ask you a tough question: have you been a good boy this year, Earl?