International space agencies such as NASA and ESA are constantly on the lookout for any signs of life on Planet Mars, but it seems scientists may have already stumbled upon signs of extraterrestrial life there way back in the 1970s.

According to a CNET report, “Life on Mars” was already a possibility during the ‘70s when NASA’s Viking Mission brought back signs that organic life forms exist on the Red Planet.

According to former NASA scientist Gilbert Levin who recently published an opinion piece in the Scientific American called “I’m Convinced We Found Evidence of Life On Mars in the 1970s,” his team was able to detect signs of microbial respiration, which pretty much indicated that there could be life on the dry and dusty planet.

NASA’s Viking Mission was the first space mission to ever land on the surface of Planet Mars. According to the report, the twin Viking landers of NASA discovered the signs of microbial respiration, but succeeding experiments could not trace any evidence that shows organic molecules exist on Martian soil.

Levin worked as the lead investigator of the Labeled Release (LR) experiment. The LR experiment basically included inoculating Martian soil with nutrients and looking for signs of metabolism that could lead to showing signs of microbial life forms.

NASA once more revisited the findings of the Viking mission back in 2016 after digitizing data stored in microfilms. However, the U.S. space agency has this to say, “the science team believed the LR data had been skewed by a non-biological property of Martian soil, resulting in a false positive. While arguments continue, this remains the consensus view."

Levin, however, stands by their initial assessment of the data even if other scientists he worked within the project believe the results are inconclusive. The report pointed out that it is important to consider that Levin’s concept of life on Mars could be correct if the initial conclusion is to be considered. However, since succeeding experiments could no longer show the same results, the conclusion could no longer be considered valid.

The former NASA scientist has continuously promoted his work for years and has even published an article in the journal Astrobiology in 2016 with LR co-experimenter Patricia Ann Straat. As with his new article, the 2016 piece also reiterated that NASA’s Viking mission did, in fact, bring back alien life forms from Mars.

Mars Dunes
This captivating image was taken in the north polar region of Mars by the ESA/Roscosmos ExoMars Trace Gas Orbiter’s CaSSIS camera. ESA/Roscosmos/CaSSIS