molecules essential to all life on earthâwere present in the soil. That experiment used a gas chromatograph mass spectrometer (GCMS) to heat the soil until chemicals turned to vapor, and then it separated, identified, and quantified the large number of different chemicals found. The device, refined and operated by prominent MIT biochemist Klaus Biemann, was designed to measure molecules present at a level of only a few parts per billion. The Viking arm twice failed to bring in soil for the GCMS, and so NASA and the many Viking watchers had to wait for days before the testing could begin.
When the samples did arrive, the results were both surprising and seemingly unequivocal: The instrument measured no indigenous organic molecules in the soil, indicating that Martian soil had even less carbon in it than the barren lunar soils brought to Earth during the Apollo program. The strongest organic concentrations it measured were minute trace chlorine-based organics written off as contaminants brought from Earth. Without organics, the scientists concluded, there could not be life, and so any experiment suggesting otherwise had to be reinterpreted. The anticipation that Viking just might delight the world by finding life on Mars quickly turned to a conviction that Mars was lifelessâwithout organics, without water, and seemingly with compounds all around that rapidly bound other elements to oxygen and made them inaccessible to potential life. A consensus quickly formed that the reactions in Levinâs experiment and the others had to be chemical and not biological, and thatâs the way the Viking results were presented to the world and understood by the scientistsâall except for Levin and a handful of others, that is.
â¢Â   â¢Â   â¢
The fact that at both Viking sites radioactive carbon dioxide appeared in significant amounts during his experiment and didnât appear during the controls, that the experiments met all the criteria set out before launch for a positive finding of biological activity and life, was too much for Levin to leave undefended and let go. And so for more than thirty years he has done just thatâreminding one and all about the Labeled Release results, citing tests of his experiment in extreme environments around the world, and working hard to knock down all the alternate explanations offered. Others have joined the fray in recent years, and Biemannâs mass spectrometer has been found wanting in a number of reviews by respected scientists. Those men and women donât necessarily endorse Levin and his conclusions, but their research found numerous instances where the GCMS instrument would (in theory) and did (during testing) miss the presence of certain organic compounds in extreme Earth environments, especially when their concentrations were low. A 2010 paper by two prominent astrobiologists, Rafael Navarro-González of the National Autonomous University of Mexico and Chris McKay of NASAâs Ames Research Center, went further: They concluded the GCMS actually destroyed organics by heating them. And the chlorine-based organics that Viking scientists wrote off as trace contaminants from Earth were precisely what would be left behind if Martian organic material were heated along with surrounding Martian soil.
Even Biemann, who defends his Mars work vigorously as having determined that the Viking landing sites could not and did not support life, nonetheless does not believe it represents a final word on Martian biology. He ended a recent defense by writing: âFuture missions to Mars will sooner or later answer the question of organic matter at the surface or in the near subsurface of that planet. It will require carefully designed instrumentation to carry out well planned experiments and thoughtful interpretation of the resulting data.â The implication, it would certainly seem, was that Viking did not meet that grade. The next NASA mission to
When the samples did arrive, the results were both surprising and seemingly unequivocal: The instrument measured no indigenous organic molecules in the soil, indicating that Martian soil had even less carbon in it than the barren lunar soils brought to Earth during the Apollo program. The strongest organic concentrations it measured were minute trace chlorine-based organics written off as contaminants brought from Earth. Without organics, the scientists concluded, there could not be life, and so any experiment suggesting otherwise had to be reinterpreted. The anticipation that Viking just might delight the world by finding life on Mars quickly turned to a conviction that Mars was lifelessâwithout organics, without water, and seemingly with compounds all around that rapidly bound other elements to oxygen and made them inaccessible to potential life. A consensus quickly formed that the reactions in Levinâs experiment and the others had to be chemical and not biological, and thatâs the way the Viking results were presented to the world and understood by the scientistsâall except for Levin and a handful of others, that is.
â¢Â   â¢Â   â¢
The fact that at both Viking sites radioactive carbon dioxide appeared in significant amounts during his experiment and didnât appear during the controls, that the experiments met all the criteria set out before launch for a positive finding of biological activity and life, was too much for Levin to leave undefended and let go. And so for more than thirty years he has done just thatâreminding one and all about the Labeled Release results, citing tests of his experiment in extreme environments around the world, and working hard to knock down all the alternate explanations offered. Others have joined the fray in recent years, and Biemannâs mass spectrometer has been found wanting in a number of reviews by respected scientists. Those men and women donât necessarily endorse Levin and his conclusions, but their research found numerous instances where the GCMS instrument would (in theory) and did (during testing) miss the presence of certain organic compounds in extreme Earth environments, especially when their concentrations were low. A 2010 paper by two prominent astrobiologists, Rafael Navarro-González of the National Autonomous University of Mexico and Chris McKay of NASAâs Ames Research Center, went further: They concluded the GCMS actually destroyed organics by heating them. And the chlorine-based organics that Viking scientists wrote off as trace contaminants from Earth were precisely what would be left behind if Martian organic material were heated along with surrounding Martian soil.
Even Biemann, who defends his Mars work vigorously as having determined that the Viking landing sites could not and did not support life, nonetheless does not believe it represents a final word on Martian biology. He ended a recent defense by writing: âFuture missions to Mars will sooner or later answer the question of organic matter at the surface or in the near subsurface of that planet. It will require carefully designed instrumentation to carry out well planned experiments and thoughtful interpretation of the resulting data.â The implication, it would certainly seem, was that Viking did not meet that grade. The next NASA mission to
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