The oldest material on Earth which has yet been dated by man is a zircon mineral that is 4.4 billion years old and comes from a sedimentary gneiss in the Jack Hills of Australia's Narre Gneiss Terrane. It is the most ancient fragment of the earth's crust so far identified, formed approximately 150 million years after the planet itself. In August 2007, scientists reported finding the world's oldest diamond crystals, encased inside the zircon crystals. The image was acquired by ASTER on Oct. 12, 2004. With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of about 50 to 300 feet, ASTER images Earth to map and monitor the changing surface of our planet and is one of five Earth-observing instruments launched Dec. 18, 1999, on NASA's Terra satellite. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team
