 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
Martian Meteorite Measurements Give Information On Planet Evolution
Scientists in the department of Geology and Geophysics at Yale University have devised a method to precisely date the timing and temperature of a meteorite impact on Mars that led to ejection of a piece of the planet into space and its eventual impact on Earth. Meteorites are the main source of mass exchange between planets and carry with them characteristic clues about the nature and history of the planets or planetesimals where they originated, the impacts that dislodged them, and the time they spent in space. Kyoungwon Kyle Min, postdoctoral fellow in geology, reported an innovation for determining the timing and temperatures of ancient impacts that liberate meteorites from extraterrestrial bodies such as Mars. To measure both the age and thermal history of the piece of Martian rock, Min assayed the natural radioactive decay of uranium and thorium to the gas helium in these meteorites, and combined it with knowledge of how temperature affects helium loss over time. This (U-Th)/He dating method, used on single grains of minerals in the "Los Angeles" Martian meteorite gave a far more accurate picture than the conventional method of analyzing chunks of meteorite. The "helium age" of about three million years corresponds with the estimated cosmogenic space exposure age. According to co-author Assistant Professor Peter W. Reiners, "The three million-year age of this meteorite is also important because other meteorites we're working on, including some Martian ones, are several hundred million to billions of years older. These methods allow us to better understand both the timing and dynamics of ancient impacts on other planets, and how these events relate to interplanetary material transfer." Scientists have long looked at meteorites to answer the question of whether there is now, or once was, life on Mars. They now can compare data from meteorites with the observations of space vehicles to learn more about past activities on the surface of Mars. Stefan Nicolescu and James Greenwood from Yale University co-authored the study supported by a grant from the National Science Foundation. Related Links Yale University SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express 
The Other Martian Meteorite
by Astrobiology MagazineMoffett Field CA (SPX) Sep 16, 2004 Perhaps the most famous of the martian meteorites was discovered at Allen Hills, Antarctica, and spawned a controversy about fossil-shapes and whether Mars could once have supported more favorable conditions than today.
|
|
| |||||||||
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service. |
