Earthly petroleum contamination reshapes Mars biosignature search

A new study shows that pristane and phytane in the Murchison meteorite exist in equal (racemic) amounts consistent with terrestrial petroleum contamination rather than fresh Martian biology, refining how scientists distinguish biological from non-biological organics and providing a practical test for the Rosalind Franklin rover’s MOMA instrument in the 2030 ExoMars mission. While Mars may have hosted life, the finding highlights the need for careful contamination-aware biosignature analysis when studying meteorites and Martian samples.