Purdue News

August 1, 1989 Findings Force Scientists To Review Theories On Origin And Travels Of Meteorites Vienna, Austria — Scientists attending the 52nd Annual Meeting of the Meteoritical Society this week have concurred with a Purdue University researcher who first theorized that differences exist between meteorites found in Antarctica and those found in other locations. "Participants at the workshop agreed that there are some very distinctive differences between these two groups of meteorites," says Christian Koeberl, professor of geochemistry at the University of Vienna and co-convener for the workshop. "At this time, however, there is no agreement about the origin of those differences." Purdue Professor Michael Lipschutz, a specialist in cosmochemical research, says their consensus puts to rest speculation on whether such differences exist, and may lead scientists to re-think theories of how meteorites travel to earth. Lipschutz first proposed that a wide range of differences set the Antarctic meteorites apart from the non-Antarctic samples in 1985. Since that time, there has been speculation in the scientific community of whether such differences actually exist, and if so, could they be caused by preterrestrial events. "These findings open a whole new area of research and will prompt many questions," Lipschutz says. "One such question, for example, is why do these differences exist? It may be that our picture of how meteorites fall to Earth is wrong or incomplete." For example, Lipschutz says, it had been widely believed that the meteorites on Earth originated from the same "pool of matter," falling to Earth on a random basis. "It may be that we have different pools or streams of matter hitting Earth at different times," Lipschutz says. The differences may also lead researchers to new theories or findings, he adds. "One possibility is that the samples in Antarctica are giving us a look at planets and/or planetary regions we have never seen before because they no longer exist or perhaps because they are no longer in a position to send material to earth by collision," Lipschutz says. He notes that the Antarctic meteorites fell to Earth hundreds of thousands of years earlier than meteorites found in other parts of the world. Since Lipschutz and his students first reported evidence of chemical differences between the two groups of meteorites, scientific groups from around the world have reported differences for such properties as element concentrations, isotopic composition, textures, types of meteorites found and percentages of types found. These differences were examined at length July 27-28 during a special workshop organized by the Lunar and Planetary Institute and the University of Vienna. The dates of the workshop were set to precede the annual meeting of the Meteoritical Society, which meets July 31-Aug. 4. Lipschutz and Purdue Professor Stephen Samuels were invited to attend the workshop and meeting. Samuels, associate professor of mathematics and statistics, has collaborated with Lipschutz on the statistical aspects of the differences. Purdue News Service: (765) 494-2096; purduenews@purdue.edu