NASA’s Curiosity rover recently discovered high amounts of methane in the air on Mars, leading to excitement whether this was an indication of life on the Red Planet, or beneath its surface. However, later it was confirmed that the methane had fallen back to usual levels.
Causes for this variation:
High amounts of methane were a transient methane plume, which has been observed in the past. Curiosity, unfortunately, doesn’t have the instruments to determine whether the source of methane is biological or geological. Further, scientists have yet to figure out a pattern for Martian’s transient plumes.
- On Earth, methane (CH4) is a naturally occurring gas. Most of the methane on Earth is produced in biological processes — some of it by microbes, and some occurring as underground natural gas that had been formed by earlier generations of microbial life.
- Many of these methane-producing microbes live in the digestive systems of animals, especially cows.
- However, methane can also be produced by abiotic processes (those that do not involve living organisms).
- It has been found to occur in formations such as rocks, springs and aquifers, and studies have concluded that it was formed there by chemical reactions between carbon and hydrogen atoms at low temperature.
- Once it is released into the atmospheres of either Earth or Mars, methane is relatively short-lived.
- Methane concentrations on Earth is over 1,800 parts per million.
Significance of its discovery on Mars:
- Since the time the gas was first detected on Mars, it has been considered a potential biomarker.
- Scientists are hoping to detect the source of the gas, and in the process clues that might point to the existence of life on the Red Planet.
To determine where the plumes are located on Mars, scientists would need a clearer understanding of these plumes, combined with coordinated measurements from other missions.
Curiosity is a car-sized robotic rover exploring Gale Crater on Mars as part of NASA’s Mars Science Laboratory mission (MSL).
The rover’s goals include investigation of the Martian climate and geology; assessment of whether the selected field site inside Gale Crater has ever offered environmental conditions favorable for microbial life, including investigation of the role of water; and planetary habitability studies in preparation for future human exploration.