|Self portrait of Curiosity Rover at a drilling site on Mars. The drilled hole can be seen on the Martian surface. This location was not part of this latest study. (Courtesy: NASA/JPL-Caltech/MSSS)|
Organic molecules have been found in ancient rocks under the surface of Mars. The discovery was made by NASA’s Curiosity Rover by drilling into mudstone that was laid down 3.5 bn years ago at the bottom of a Martian lake. The molecules found include sulphur-rich thiophenes, aromatic hydrocarbons, such as benzene, and aliphatic hydrocarbons such as propane.
While the presence of these molecules does not prove that life once existed on the red planet, the discovery suggests that conditions on Mars could have been like those here on Earth when life first emerged more than 3 bn years ago.
The discovery is reported in the journal Science by NASA’s Jennifer Eigenbrode and an international team of scientists. They used Discovery’s Sample Analysis at Mars (SAM) instrument to examine samples that had been gathered from Mars’ Gale crater using a drill that can probe 5 cm below the surface.
SAM works by heating rock samples to release any organic compounds that may be present. The emitted gases are then analysed using a gas chromatograph mass spectrometer and a laser spectrometer.
This is not the first time that Curiosity has detected organic molecules, but previous measurements were considered unreliable because of possible sample contamination and unwanted chemical reactions.
Organic molecules found in ancient Martian rocks, Hamish Johnston, Physics World
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