Just in time for the new year, the Bad Astronomy Blog has posted a discussion of the intricacies of defining a year. It's fascinating stuff, and a really good illustration of the principle that the more you learn, the less you know. Quote:
So there you go. As usual, astronomers have taken a simple concept like "years" and turned it into a horrifying nightmare of nerdy details. But really, it’s not like we made all this stuff up. The fault literally lies in the stars, and not ourselves.Enjoy!