The twin Viking landers of NASA hit the bottom of Mars in 1976, with the aim to get an answer to one of the greatest questions of all time: is life in the Red Planet recognizable? The most important researcher of the life detection experiment of the Vikings & Labeled Release (LR) was Gilbert Levin. Although the instrument received positive reactions on both landing sites; the scientists could not draw a conclusion about whether these results were a testament to life on Mars.
However, Levin himself concluded in 1997 that the experiment was able to recognize life on the Red Planet. Since then he has been an advocate of this position.
Now, more than 40 years after the Viking landers have experimented, Levin is of the opinion that the American space agency NASA has not properly monitored the Viking results. "I'm sure NASA knows there's life on Mars," Levin stated on David Livingston's popular online program "The Space Show."
Not only did he express disappointment, he also asked for a re-examination of Viking LR data by an objective panel.
He added that a number of landers, robbers and orbits have received proof in the past 40 years that there is life on Mars today. There is "substantial and indirect evidence for the existing microbial life on Mars", he stated on the show.
He noted, for example, that NASA's Curiosity Rover found cyclical and seasonal spikes in Mars methane and, as we know, more than 90% of earth's methane is produced in the atmosphere by microbes and other organisms. "This is really hard to ignore as evidence for life."
However, the team from Curiosity missions has stated that methane can also be produced by the chemistry of water rock, so that is not really convincing evidence of life on Mars.
Then came the news in July 2018 that the Mars Express mission of the European Space Agency apparently found an underground lake below about a mile of ice near the South Pole of the Red Planet. Apart from that, other spacecraft have also seen traces of water on Mars over the years and now "we are being overloaded with an underground lake … so water is no longer the problem," Levin said.
Levin also spoke about the Curiosity visual language, which can be interpreted as a representation of fossilized stromatolites. Here on earth these types of structures are developed by colonial microbes. There are immense similarities in these structures, he added.
According to Levin, all the information we have collected on Mars points to the fact that terrestrial micro-organisms can survive on that planet, even in the low pressure, freezing temperatures and ruthless radiation.
You may or may not agree with Levin, but you certainly can not ignore him!