October 22, 1999

Status of the "Life on Mars"
Controversy: "New Evidence from Martian Meteorites"
Meenakshi Wadhwa
Associate Curator (Meteoritics)
The Field Museum of Natural History
Chicago, IL

The current status of the "Life on Mars" debate will be discussed in light of recent studies of martian meteorites. The "Life on Mars" debate was initially sparked in August of 1996 by a group of scientists who claimed to have found evidence for fossil microorganisms in 50-100 micron-sized carbonate globules in the ALH84001 martian meteorite. Since then there have been several studies of this and other martian meteorites that have bearing on this debate.

Bio Sketch

Meenakshi Wadhwa received both her B.S. in Geology (minors in chemistry and physics) and her M.S. from Panjab University, India, and a Ph.D. in Earth and Planetary Sciences from Washington University, St. Louis, MO.

Her current position is Associate Curator (Meteoritics), The Field Museum of Natural History, and Lecturer/Research Scientist, at the University of Chicago, which followed her postoctoral geochemical studies at Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA.

Asteroid 8356 was renamed Asteroid Wadhwa by the International Astronomical Union in 1999.

Research Interests: Trace element and isotopic studies of meteorites to obtain constraints on (1) their timing of formation and (2) the processes by which they were formed in the early solar system. Martian meteorites are of particular interest, since they can provide insights into the evolution of Mars over geologic time.

Click Here for the FMNH meteorite catalog.

Report of SMSI meeting of October 22, 1999

The meeting was called to order by Bill Mikuska at ~7:15PM. The featured speaker, Dr. Meenakshi Wadhwa, made a return appearance to update the SMSI audience re: the latest evidence from the Martian meteorites and the current status of the "Life on Mars" debate. That the debate has not been settled was stated without further ado.

Different scientists have studied similar aspects of the same material, oxygen isotope studies for example, and reached completely opposite conclusions, one of which supports the possibility of biogenesis while the other precludes the very same. Ditto for T.E.M. studies of the Martian magnetite samples. Formation of carbonates at low temperatures could support biogenetic theory, but there is no conclusive evidence to support this idea.

While studies of microscopic gas samples taken from Shergottite meteorites allow for positive identification of "Martian" rocks, ambiguity about the age old question of "Life on Mars" seems to have become more complex.

Report submitted by John Macdonald, Recording Secretary