There are numerous mysteries on Mars that scientists from around the world are working to solve. One of the most tantalizing of those mysteries is reports of methane detection on the Red Planet. Here on Earth, significant amounts of methane is produced by microbes helping livestock digest plants. The digestion process ends with livestock exhaling gas into the air.
Finding methane on Mars is an important discovery because it could imply that microbes were or are alive on the planet. However, scientists admit the methane could have nothing to do with microbes or any other type of life and could be from geological processes that involve the interaction of rocks, water, and heat to produce methane. Before scientists can determine the source of methane on the Red Planet, they have to first determine why some instruments detect methane while others don’t.
The Curiosity rover has repeatedly detected methane above the surface of Gale Crater. However, the ESA ExoMars Trace Gas Orbiter hasn’t detected methane higher in the planet’s atmosphere. The Curiosity rover has repeatedly detected methane above the surface of Gale Crater. Its Tunable Laser Spectrometer has measured less than one-half part per billion in a volume of methane on average in Gale Crater. That’s equivalent to a pinch of salt diluted in an Olympic-sized swimming pool.
However, there have also been spikes up to 20 parts per billion in volume. Both the ESA and NASA’s instruments are so precise; scientists are struggling to figure out the discrepancy between the two instruments. Some have suggested that the Curiosity rover might be emitting the gas, but scientists put significant effort into looking at every detail of the rover to ensure its measurements are correct, and they say the measurements are correct.
One possibility is that since the Tunable Laser Spectrometer only operates at night when no other Curiosity instruments are working, and the Martian atmosphere is calmer, enables it to detect methane. Scientists think that possibly methane is seeping from the ground and builds up near the surface where curiosity can detect it. By comparison, the Trace Gas Router requires sunlight to pinpoint methane about three miles above the planet’s surface. Methane near the planet’s surface at night would be mixed into the broader atmosphere during the day, diluting it to undetectable levels. Despite efforts, scientists have yet to solve the mystery of the methane levels on the planet, but work is ongoing.