2013/04/16 by William Bains, Bains, William
Physics and Astronomy · #Astro and Planetary Science #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Planetary Science and Exploration #Space Science and Extraterrestrial Life
paper · pdf · doi:10.48550/arxiv.1304.4429
openalex publication_date 2013/04/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The MSL Lander Curiosity has recently detected methyl halides coming from heated samples of Martian soil. This is reminiscent of similar findings in the Viking Lander spacecraft. In the 1970s a consensus developed quickly explaining the methyl halides as contamination originating from the spacecraft, and ignoring lines of evidence that the two compounds originated from Mars, and that they could not have originated from the proposed spacecraft chemistry. I discuss why this consensus developed from the understanding of biochemistry and geochemistry of 1976, despite its implausibility. Subsequent explanations for the Viking methyl halides are more plausible but still not proven. The Curiosity rover results are also being explained as a result of on-spacecraft chemistry. I urge caution in this interpretation, in light of the historical Viking example: it is better to leave unexplained data unexplained than to lock in an explanation that precludes future developments.