Larry R. Nittler
Cosmochemistry; presolar grains in meteorites; secondary ion mass spectrometry and planetary remote sensing
B.A., Physics, Cornell University , 1991
Ph.D., Physics, Washington University, 1996
Cosmochemist Larry Nittler studies the origin and evolution of stars, the Galaxy, and the Solar System, both through laboratory analysis of extraterrestrial materials like meteorites and interplanetary dust particles (IDPs) and through planetary remote sensing via spacecraft.
Nittler is especially interested in presolar grains and organic matter contained in meteorites and in what they can tell us about our cosmic origins. He develops and uses advanced microanalytical techniques to locate and analyze these particles. The solar system formed about 4.5 billion years ago from a cloud of gas and dust. Most of the original dust grains were vaporized during solar system formation, but in the 1980s, researchers discovered that a fraction of these particles survived, trapped in meteorites. Presolar grains are tiny - about one thousandth of a millimeter in diameter. They predate other solid material in the solar system and are believed to have formed in winds and explosions of ancient dying stars. The unusual abundance ratios of different isotopes in presolar grains compared with other solar system products are their defining feature. They give researchers information about a number of processes, including how elements are synthesized inside stars, how the Milky Way galaxy evolves, and what the first solar system materials were.
As Deputy Principal Investigator on NASA’s MESSENGER mission to Mercury, Nittler is playing a leading role in determining the chemical composition of the Solar System’s innermost planet. MESSENGER, led by former DM director Sean Solomon, has been returning a wealth of scientific data since entering obit around Mercury in March 2011. By analyzing x-ray and gamma-ray signals emitted by rocks at the planet’s surface, Nittler and colleagues have determined that Mercury is surprisingly rich in magnesium, sulfur and sodium and low in iron. By comparing elemental maps to other data sets, Nittler is unraveling clues to the origin and geological history of Mercury, an end-member of planetary formation in our solar system.