By David Alire Garcia TEOTIHUACAN, Mexico (Reuters) - A Mexican archeologist hunting for a royal tomb in a deep, dark tunnel beneath a towering pre-Aztec pyramid has made a discovery that may have brought him a step closer: liquid mercury. In the bowels of Teotihuacan, a mysterious ancient city that was once the largest in the Americas, Sergio Gomez this month found "large quantities" of the silvery metal in a chamber at the end of a sacred tunnel sealed for nearly 1,800 years. "It's something that completely surprised us," Gomez said at the entrance to the tunnel below Teotihuacan's Pyramid of the Plumed Serpent, about 30 miles (50 km) northeast of Mexico City. Some archeologists believe the toxic element could herald what would be the first ruler's tomb ever found in Teotihuacan, a contemporary of several ancient Maya cities, but so shrouded in mystery that its inhabitants still have no name.
By Will Dunham WASHINGTON (Reuters) - Deep beneath Yellowstone National Park, one of the world's most dynamic volcanic systems, lies an enormous, previously unknown reservoir of hot, partly molten rock big enough to fill up the Grand Canyon 11 times, scientists say. Researchers on Thursday said they used a technique called seismic tomography to a produce for the first time a complete picture of the volcanic "plumbing system" at Yellowstone, from the Earth's mantle up to the surface. Scientists already knew of a large magma chamber under Yellowstone that fed the eruptions 2 million, 1.2 million and 640,000 years ago. "The existence of the second magma chamber does not make it any more or less likely that a large volcanic eruption at Yellowstone will occur.
By Irene Klotz CAPE CANAVERAL, Fla. (Reuters) - NASA on Thursday marked the silver anniversary of the Hubble Space Telescope with fireworks, of a celestial kind, conveyed by the orbiting observatory itself. To commemorate Hubble's launch on April 24, 1990, NASA selected a picture of a stellar nursery located about 20,000 light-years away in the constellation Carina.