|Simon Wilde, a professor at Curtin University of Technology in Perth, Australia, shows off a 4.4 billion-year-old zircon crystal at University of Wisconsin|
The tiny piece of zircon crystal scientists believe is 4.4 billion years old was the focus of attention the at event held at the University of Wisconsin Madison in a rare public appearance for the crystal.
The school's professor of geology and geophysics, John Valley, startled researchers in 2001 when he concluded the tiny zircon crystal proves that early Earth was cool enough to have oceans and continents, and was not a boiling ocean of magma as previously believed.
After the U.S. exhibition, the object will be returned to Australia where it was discovered in 1984.
Some information for this report provided by AP.