According to new analysis of an experiment performed by the Viking landers, there's evidence of microbial life in the Martian soil and it may have been detected some 36 years ago. One of the authors of a new paper puts it "on the basis of what we've done so far, I'd say I'm 99 percent sure there's life there." Whoa.
It was one of a set of four different tests that the Viking landers carried out to detect life on Mars. In the Labeled Release (LR) experiment, the lander took samples of Martian soil and dumped it into a chamber which was sealed up. A drop of a slightly radioactive nutriet solution was added and then the air above the soil sample was monitored to see if there was anything alive in the soil metabolizing those nutrients.
The LR experiment detected a steady stream of radioactivity coming out of the soil after the nutrient soluton was added. The other three experiments didn't produce any results, and the consensus back in 1976 was that the LR result was some chemical reaction caused by rocks and not the sign of any microbial life.
New research that was published last month in the International Journal of Aeronautical and Space Sciences has taken a new look at the Viking LR experiment results, and the authors of the paper are confident that the best way to explain the data is through the existence of microbial life.
Researchers found that they could "clearly distinguish between active and control Martian LR experiments," meaning that that there was a significant difference between experiments where they were sure there wasn't life, and where there might have been life.
Still, this isn't proof that we've found life on Mars just yet, but there's hope that we will soon.