It looks like a lot of people think the presence of the oxidizer perchlorate is the cause of the false positive, but there isn't consensus yet. ``` On August

It looks like a lot of people think the presence of the oxidizer perchlorate is the cause of the false positive, but there isn't consensus yet. ``` On August 2008, the Phoenix lander detected perchlorate, a strong oxidizer when heated above 200 °C. This was initially thought to be the cause of a false positive LR result. However, results of experiments published in December 2010 propose that organic compounds "could have been present" in the soil analyzed by both Viking 1 and 2, since NASA's Phoenix lander in 2008 detected perchlorate, which can break down organic compounds. The study's authors found that perchlorate can destroy organics when heated and produce chloromethane and dichloromethane as byproduct, the identical chlorine compounds discovered by both Viking landers when they performed the same tests on Mars. Because perchlorate would have broken down any Martian organics, the question of whether or not Viking found organic compounds is still wide open, as alternative chemical and biological interpretations are possible. ... In a paper published in December 2010, the scientists suggest that if organics were present, they would not have been detected because when the soil is heated to check for organics, perchlorate destroys them rapidly producing chloromethane and dichloromethane, which is what the Viking landers found. This team also notes that this is not a proof of life but it could make a difference in how scientists look for organic biosignatures in the future. ```[0] It's funny that perchlorate is likely what confounded the LR experiment, as the discovery of perchlorate in the soil made a lot of folks less optimistic about life being able to survive on the Martian surface.[1] [0] https://en.wikipedia.org/wiki/Viking_lander_biological_experiments https://en.wikipedia.org/wiki/Viking_lander_biological_exper... [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5500590/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5500590/