Viking Data Suggests Life?
But has it already been found? Some scientists say yes.
Researchers from universities in Los Angeles, California, Tempe, Arizona and Siena, Italy have published a paper in the International Journal of Aeronautical and Space Sciences (IJASS) citing the results of their work with data obtained by NASA's Viking mission.
The twin Viking 1 and 2 landers, which launched in August and September of 1975, successfully landed on Mars in July and September of the following year. Their principal mission was to search for life, which they did by digging into the ruddy Martian soil looking for signs of biological activity.
The Viking Labeled Release experiment added nutrient to samples of Mars soil, and then checked to see if microbes that may have been living in the soil expelled any waste products. Gas was released, but scientists could not rule out that this could have been the result of abiological chemical reactions.
Now, 35 years later, one team of researchers claims that the Viking landers did indeed detect life within their soil samples. Their study looked at the time series of what happened between the moment of adding nutrient and the release of gas, and said it was similar to what happens when microbes living in soil on Earth take up nutrients and exhale waste.
"Active soils exhibited rapid, substantial gas release," the team's report states. "The gas was probably CO2 and, possibly, other radiocarbon-containing gases."
By applying mathematical tools from the field of complexity analysis to the Viking data, the researchers found that the martian samples behaved differently than a non-biological control group.
However, a process of conclusively identifying life has not yet been perfected -- not even here on Earth.
ďItís an interesting and novel approach, but I donít think itís necessarily the definitive proof of life that they are claiming,Ē says Michael New, Astrobiology Discipline Scientist at NASA. ďAre there abiological processes that could also produce that same sort of signal?Ē
New says just because the pattern seen in the results resembles life, doesnít necessarily mean it is life.
"In the absence of a predictive model, it's hard to say that when two series of measurements have the same properties, they are produced by the same phenomenon," he says.
The new study shows that questions about the old Viking data still live on. Future missions, including Curiosity rover, will hopefully help us find some answers about the potential for life on Mars.
The new research paper can be found here.
Editor's note: This story was adapted from a Universe Today news release, with additional comments added on April 16, 2012.