The concentration of methane in the local Martian atmosphere has been measured periodically by scientists using the Sample Analysis at Mars (SAM) instrument’s Tunable Laser Spectrometer (TLS) on the Curiosity rover. The detection of methane, which is not expected to last for very long in the Martian atmosphere, is a tantalizing potential bio-signature, suggesting the presence of modern life on Mars. Typically, there is a debate over whether the methane detected is due to biologic or geologic processes, but the authors of a new study suggest that the seasonal variation in methane detected in Gale crater may be inconsistent with known geologic processes.

Background levels of methane in Mars’ atmosphere show strong seasonal variations