Meteorite analysis. Researcher Dolores Hill prepares a meteorite sample for analysis of its minor constituent chemicals (trace elements). Meteorites are pieces of interplanetary rock and metal which fall to Earth without being burnt up in the atmosphere. Studies of the chemical composition of meteorites may allow scientists to determine how an interstellar disk of gas and dust around the early Sun condensed to form the planets. Hill is a Senior Research Specialist at the Lunar and Planetary Laboratory at Arizona University, USA. Photographed in 1997.