- Oct 1, 2011
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The Viking Mars Missions May Have Discovered Life in 1976 | Popular Science
The View From Viking I NASA
Since the Viking Mars probes traveled to the red planet back in 1976, NASA has sent several more probes, landers, and rovers to the Martian surface to study the planets geology and search for signs of microbial life. But the evidence for life may have been hidden in Vikings data all along. A new analysis of the data collected by probes Viking 1 and Viking 2 suggest the missions found evidence of microbial life more than three decades ago.
The new analysis centers on one of the three experiments carried by the probe: the Labeled Release (LR) experiment. This instrument searched for signs of life by mixing samples of Martian soil with droplets of water containing nutrients and radioactive carbon. If the soil contained microbes, the reasoning went, they would metabolize these carbon atoms and nutrients and release either methane gas or radioactive carbon dioxide, either of which would tip off the probes that life existed in the soil.
Thats exactly what happened. But other experiments aboard Viking didnt back up the LR, and NASA scientists had to dismiss the LRs findings as anomalous.
But now an analysis by a University of Southern California neurobiologist (and former NASA space shuttle project director) and a mathematician from Italys University of Siena could reverse that thinking. They used a technique called cluster analysis, which clusters together similar-looking data sets, to see what would happen. They found the analysis created two clusters: one for the two active experiments on Viking and the other for five control experiments.
Further, when they compared Vikings data to confirmed biological sources on Earth, like temperature readings from a lab rat, the analysis correctly clustered the biological readings with the active Viking experiment data, separate from the non-biological data in the control experiments. All that essentially means that the cluster analysis, when fed a good deal of data from both biological and non-biological sources, correctly separates the two types of data. And when it does so, it lumps the Viking data into the biological category.
Thats not concrete evidence for microbial life on Mars. Its merely concrete evidence that there is a stark difference between Vikings LR experiment data and the control experiment data. And its evidence that the Viking data tracks with biological rather than non-biological data. More study is necessary (isnt it always?), but if the cluster analysis is to be believed then our first shot at detecting microbial life in the soils of Mars may have hit pay dirt--and we didnt even realize it.