More than you ever wanted to know about our calendar: Panic Blog – “Once in a Blue Moon”.
Much of this I already knew (being the geek that I am), but some of it was new and interesting. For instance:
Surprisingly, while just about every year between 1972 and 1999 required a leap second to keep the clock synchronized with the Earth’s rotation, there have only been two leap seconds added in the last ten years. The Earth has sped up just a bit, and no one knows why.
For the same reason, the Earth’s rotation is also slowing down and will eventually match the orbit of the moon. At that point, billions of years from now, both a day and a month will last for around 47 of our current 86,400-second-long days. One side of the Earth will face the moon; the other will never see it again.
A single day lasting about a month and a half of our current time. It boggles the mind.