NASA's curiosity rover has added a new mystery to scientists studying Mars, with rover samples showing a seasonal change in oxygen levels near the surface of the Gale crater on the red planet.
According to a new study, the results of which were published in a paper in the Journal of Geophysical Research: Planets, oxygen behaves in a mysterious way on Mars. According to NASA, NASA found that oxygen levels in spring and summer increased by as much as 30 percent.
NASA in its press release notes that this pattern repeats itself every spring, although the amount of oxygen added to the atmosphere varies. According to their conclusions, some specific conditions or processes on Mars likely produced oxygen and then took it away.
According to data from the Mars Chemistry Portable Laboratory (SAM), located in the belly of Rover Curious, 95% of the Martian atmosphere is carbon dioxide by volume. The other gases are: 2.6% molecular nitrogen, 1.9% argon (Ar), 0.16% molecular oxygen (O2) and 0.06% carbon monoxide (CO). Oxygen, needed for breathing by most creatures on Earth, is barely present on Mars.
While scientists have found that nitrogen and argon follow a predictable seasonal pattern, shifting and declining concentrations in the Gale Crater, oxygen did not behave as expected. "The first time we saw it, it was just a push in the mind," said Susil Atrea, a professor of climate and space science at the University of Michigan in Ann Arbor. Atrea is a co-author of the paper.
Mars experts have tried to explain the rise and fall in oxygen levels on the red planet. The possibility of CO2 or water (H2O) molecules releasing oxygen when decomposed into the atmosphere has been considered. But it was concluded that it would take five times as much water over Mars to produce extra oxygen.
Further, CO2 is decaying too slowly to be generated in such a short time, according to NASA. Scientists are still struggling to explain these phenomena why oxygen rises and falls on the planet. "The fact that oxygen behavior is not perfectly repeatable every season has made us think that this is not a problem related to atmospheric dynamics. It has to be some chemical sources and sinks that we still can't care for, "said Melissa Trainer, a planetary scientist at Goddard Space Flight Center, NASA in Greenbelt, Maryland who led the research.
Much like oxygen, another gas that has a seasonal rise and fall on the Galle crater is Methane. Rover's Mars Curiosity instrument found that as methane rises and falls seasonally, it increases by about 60% in the summer months for unexplained reasons. This is another mystery that scientists have yet to solve.
NASA points out that both Oxygen and Methane can be produced both biologically (eg from microbes) and abiotic (from water-and-rock chemistry). NASA says the SAM team will continue to measure atmospheric gases so that scientists can collect more detailed data during each season.