I've always been a huge fan of Christmas (as has my Mum), & with that in mind, my Mum got me this book for Christmas a couple of years back. I can honestly say I picked it up & didn't put it down again till it was finished. And then I read it again!
It's absolutely fascinating - exploring all the 'mythical' things associated with Christmas & applying science to them to test their viability. In the case of Santa's reindeer, it's proven that they would all be female, as the males lose their antlers, but the females keep theirs till they have their young - FACT! Another favourite of mine (and a question I'm sure children all over the world ask) is how does Santa fly, in all weathers, all around the world, delivering all those presents to all the children IN ONE NIGHT? That question & many more are answered in this fun book. As for the Bethlehem Star & why Santa is so fat, well, you'll have to get a copy of the book & read it for yourself - I won't spoil it for you.
Seriously though, I never thought science could be this interseting! So interesting, in fact, that you hardly think you're reading science at all. And it really does help bring all that whimsical wonder back to Christmas (I'll be listening for Santa's all-female reindeer team next year!).