New analysis supports discovery of life on Mars by Viking landers

View of terrain near Viking 1 lander on Mars, with trenches dug in the soil for the life-detection experiments. Credit: NASA/JPL

The question of whether or not the Viking landers found evidence of microbial life on Mars in the 1970s is one of the most hotly debated issues in space exploration and continues to this day. Most scientists concluded that the seemingly positive results of the Labeled Release (LR) life-detection experiments were the result of unusual chemical activity in the soil instead of life, based largely on the lack of organics found in the soil samples. This was the single biggest argument against the life hypothesis, as any microbes would need to be composed of organic material.

Results from the Phoenix mission which landed on Mars in 2008 indicated that perchlorates in the soil could explain the apparently missing organics, which would destroy any organic material. Other Earth-based studies have also shown that the Viking experiments may not have been sensitive enough to find organics at very low levels, similar to those found in soil in Antarctica or the Atacama desert, the most Mars-like places on Earth.

Now, another new study conducted over the past six years has concluded that Viking did indeed find life in the Martian soil, based on an updated anaysis of the results using mathematical complexity. The level of complexity found was similar to that in biological systems on Earth. Non-biological processes have a naturally less complex degree of order to them.

The study was published in the International Journal of Aeronautical and Space Sciences.

“On the basis of what we’ve done so far, I’d say I’m 99 percent sure there’s life there,” said Joseph Miller, from the University of Southern California Keck School of Medicine. He adds: “To paraphrase an old saying, if it looks like a microbe and acts like a microbe, then it probably is a microbe. The presence of circadian rhythmicity and a high degree of mathematical complexity or order in the LR data most likely means Viking discovered microbial life on Mars over 35 years ago.”

The data is compelling, if not definitive yet. Further results are expected to be announced next August, according to Discovery News.

The paper is available here (PDF).

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