Beware ambiguous biosignatures

Sent to search for signs of ancient microbial life, Nasa’s Perseverance rover landed in the Jezero crater just north of Mars’s equator in February 2021. Since then, instruments on board Perseverance have been busy gathering samples and data from the red planet. Among them was an image of Martian rocks, taken with its right Mastcam-Z camera, that looks very much like a decapitated head, bringing back memories of the infamous ‘face on Mars’ picture captured by Nasa’s Viking 1 mission in 1976.

Research we reported on this week, however, brings into question slightly more scientific interpretations of Perseverence’s data haul.