Today’s story is a little afar from where we usually talk.
In the mid-1970’s the American space agency launched two spacecrafts named Viking 1 and Viking 2. These crafts’ destination was the planet Mars. On them were a host of various chemical, physical, and geographical instruments. You see, while Mars had been orbited previously by other devices, the Viking missions were to be the first successful landing on the surface of Mars. NASA shoved as many experiments as they could onto those landers. What kinds of soil where on Mars? What compounds? Was there water? What was the atmospheric pressure?
And, perhaps the most important question, was there life?
There were four experiments packed onto those crafts dedicated solely to biology. Each one would scoop up a small sample of the soil, isolate it in a sterile chamber, then attempt to find signs of microbes or other microscopic life. There was a Gas Chromatograph – Mass Spectrometer, which would heat the soil and then identify and quantify any gases that were released. The Gas Exchange would remove the native Martian atmosphere from the sample and monitor to see if anything was breathing down there. The Labelled Release and the Pyrolytic Release experiments would try to ‘feed’ the soil simple nutrients that had been labelled with radioactive carbon-14 and watch for any signs of metabolism.
For three of them, the results were null, with no signs of any sort of life. Quite disappointing, from an exobiologist’s point of view. However, the primary investigator for the Labelled Release experiment, a researcher named Gilbert Levin, found a very different result.
Levin’s experiment showed what appeared to be metabolic activity. Both landers detected labelled gases, suggesting that something under the soil was indeed eating the nutrients. However, the results could not be duplicated a week later nor did any of the other experiments bring back anything close to a positive result. NASA explained away Levin’s positive tests as contaminants and officially declared Mars to be a dead planet.
And, officially, Mars has stayed that way. However, Dr. Levin has continued to push forth his findings, trying to increase public knowledge of the inconclusive results of NASA’s experiments, and developing new and better ways to test for life on distant planets. One of the most promising designs is a probe to test for disparities in the chirality of surface molecules.
His Viking results have been argued back and forth for decades now, with new researchers alternatively supporting and trying to disprove his results. However, it is unquestioned that Levin’s work with NASA and his fervent support of expanding exobiological testing and discussion has left a mark in the public mind.
For more I’d recommend reading this interview with the esteemed doctor.
Sources: Stropi de Zambet for the picture, NASA website, Wikipedia, and Professor Bernie Bates of University of Puget Sound for the story.