Life on Mars: Where do we stand after six years of investigations?

Dr Everett Gibson

Johnson Space Center

--- Abstract - Profile ---

Abstract: The question "Is there life on Mars?" is one of the most challenging questions for the scientific community to answer. Until documented samples are returned to Earth from Mars by space probes, the only samples available for study are twenty-six undocumented, randomly selected Martian samples delivered to Earth. Martian meteorites offer a unique opportunity to study near-surface samples from Mars. Martian meteorites of widely differing ages (ALH84001 - crystallization age of 4.5 b.y. with 3.9 b.y. old carbonates; Nakhla – crystallization age of 1.3 b.y. and clays of possibly 600-700 million years age; and Shergotty – 165 m.y. crystallization age) contain evidence of water produced alteration products (hydrates, clays, sulfates, carbonates, halites, etc.). ALH84001 and Nakhla has been shown to contain indigenous reduced carbon compounds with isotopic compositions which are not products of terrestrial contaminants. Unique magnetite biomarkers are found within the ALH84001 low-temperature carbonate globules and are identical to six unique properties of magnetites produced by the reference MV-1 magnetosome bacteria. Morphological structures are present within the three Martian meteorites which are identical to fossilized bacteria. Despite more than six years of extensive research by the scientific community, the McKay et al. (1996) hypothesis of relic biogenic activity with Martian meteorites continues to be the only hypothesis that is capable of explaining all of the observed data within the samples from Mars.

PROFILE: Dr Gibson has degrees in chemistry and completed his Ph.D. (1969) in geochemistry from Arizona State University. Awarded a National Research Council (NRC) Postdoctoral Research Associate position (1969) in the Lunar and Earth Sciences Division, NASA Manned Spacecraft Center he served as Mission Science Advisor for Apollo 14 in the Lunar Receiving Laboratory where he assisted and gave scientific advice during the Apollo 14 mission. Dr Gibson was a Principal Investigator in NASA's Planetary Geology program from 1977 to 1989 studying from Martian analogues and developing models for the evolution of water and other volatiles on Mars. In 1979, he visited the Dry Valleys of Antarctica and conducted research that showed the weathering processes operating in the cold, arid region are similar to those observed on the Martian surface by the Viking landers. He has been developing analytical methods of analysis, which might be potentially useful for future studies on Martian materials either insitu, or on returned samples. As co-leader of the NASA-JSC team, which made the discovery of possible relic biogenic activity in the Martian meteorite ALH84001 Dr Gibson, was awarded NASA's Exceptional Scientific Achievement Medal. The team’s 1996 discovery showed the presence of indigenous reduced carbon and carbonate globules that might be the microfossil remains of a past Martian biota. The work has been acclaimed as one of the outstanding discoveries in science in the 20th Century. Dr Gibson presently serves as Adjunct Scientist for the European Space Agency’s Beagle 2 Mission to Mars. He is the only U.S. scientist participating in this science team. Having published more than 300 scientific papers, more than 200 of which have been presented at national and international meetings he currently serves as a geochemist-space scientist and co-leader of the Mars Meteorite Research Team at the Astromaterials Research Office, NASA Johnson Space Center. As a certified flight engineer and loadmaster for the B-17G he participates in airshows throughout America as a crewmember of the B-17G Flying Fortress TEXAS RAIDERS in which he has completed 126 missions.