Oldest Thing on Earth

If you were in Madison, Wisconsin, on Saturday, you could have stopped by the UW-Madison Geology Museum~museum/ to see the oldest known piece of Earth — a zircon crystal estimated to be 4.4 billion (!) years old. Check out the Rock Concert web site~museum/symposium/index.html for more info. The crystal is heading back to Australia, where it was discovered in 1984, to be displayed in a museum there.