It’s been more than 40 years since the Viking landers arrived on Mars in 1976. They were there to determine if life existed there. And, according to one of the NASA scientists that worked on the Viking project, they found it.
A consensus was not reached on the results of what the Viking landers found, because of the accuracy of the instruments (or lack there of) and more information gathered since that mission. But, Gilbert Levin, who was the principal investigator of the Vikings’ Labeled Release (LR) life-detection experiment says, even decades later, “I am certain that NASA knows there is life on Mars”. This, according to space.com.
Levin’s reasons for believing life on Mars is likely are some of the same reasons other scientists don’t agree. He notes that the Curiosity Rover has found cyclical, seasonal shifts in the levels of methane on the surface of the red planet. On Earth, more than 90% of the methane in the atmosphere is created by microbes and other organisms. But, water-rock chemistry can also produce methane, and it can’t yet be proven that one or the other is the cause on Mars.
Several scientists from Viking and beyond agree that the landers may have been more effective had we known more about Mars before sending them. Viking veteran, Ben Clark, who is now a senior research scientist at the Space Science Institute in Boulder, said “From what we have learned since Viking about the past history of Mars, it was even more eminently suited for the origin of life than we knew when the search began,”. He added, “A Viking lesson learned is that you had better understand the environment well before designing tests for biological activity.” But he also believes that with the knowledge we now have, it’s time to be searching for life on Mars again.
Astrobiologist Chris McKay does not think that Viking found life, and that the findings can be explained by reactive chemicals called perchlorates. But, he also says “We cannot rule out that Gil Levin is correct and that there are dormant life-forms in the Martian soil,”. And, he brings up another point. How sure must we be that Mars is truly barren of life before sending people to it? McKay said, “Are we confident enough that the Martian soil is lifeless to send astronauts … and then to bring those astronauts back to Earth? I say no.” And, that’s enough for us.
So, good luck, all of you that are ready to ship yourselves to a red planet colony. We at GGA are staying home on that first trip to Mars. You guys have a nice time fighting space microbes. See you in the end times.