The Mars Curiosity rover recently reported high levels of methane in the atmosphere of the Red Planet, an unexpected result which could hold promise for exciting new discoveries. On Earth, methane is often the product of life, but chemical processes could also be responsible for the gas found by the intrepid rover.
The robotic explorer, exploring Mars since August 2012, found the a sample of the atmosphere on the Red Planet contains roughly 21 parts per billion of methane. Currently sitting in Gale Crater, the spacecraft is not equipped with instruments able to discern whether the gas it has detected is produced within the crater, or elsewhere on the planet.
Detection of the unusually high concentration of methane came from the Sample Analysis at Mars (SAM) tunable laser spectrometer onboard the Curiosity rover.
“With our current measurements, we have no way of telling if the methane source is biology or geology, or even ancient or modern,” said SAM Principal Investigator Paul Mahaffy of NASA’s Goddard Spaceflight Center.
Why the Curiosity?
Curiosity has detected methane in the atmosphere of Mars several times before, but this is the greatest concentration ever seen by the robotic rover. Levels of the gas fluctuate significantly, and researchers are still attempting to understand why concentrations of methane vary so widely over time. Seasonal changes play a part in how much methane is seen in the Martian atmosphere, but concentrations are also marked by seemingly random peaks which remain unexplained.
“Curiosity set out to answer the question: Did Mars ever have the right environmental conditions to support small life forms called microbes? Early in its mission, Curiosity’s scientific tools found chemical and mineral evidence of past habitable environments on Mars,” the Curiosity rover team explains.
The Curiosity rover measures about three meters (10 feet) in length, 2.7 meters (nine feet) wide, and stands 2.2 meters (seven feet) high. The vehicle weighs 900 kilograms (2,000 pounds) and its arm is capable of reaching 2.2 meters (seven feet) away from the craft.
“Curiosity is about twice as long (about 3 meters or 10 feet) and five times as heavy as NASA’s twin Mars Exploration Rovers, Spirit and Opportunity, launched in 2003,” NASA officials explain.
Is that Methane I Smell?
As astronomers study the atmospheres of worlds around other stars, high concentrations of methane could be a telltale sign of life. However, on Mars as well as distant worlds, the gas can also be produced during interactions between rocks and water. Methane is the simplest of all hydrocarbons, consisting of a single carbon atom combined with four atoms of hydrogen. It is an important contributor to global climate change on our home world.
Strangely, the Trace Gas Orbiter sampling the upper layer of the Martian atmosphere has been unable to detect any signs of methane at extreme altitudes. Researchers hope that by combining observations from the surface and upper atmosphere of Mars, they may be able to better understand the source of the gas.
Researchers will need further study of the data in order to determine the source of these high levels of methane recently measured by the Curiosity rover. It is unlikely the gas is the result of life currently existing on Mars, but the finding could provide additional knowledge about the history of geology on the Red Planet.