14 DAY TRIAL // Scientists determined a long time ago that Mars' atmosphere would make all of the planet's methane resources disintegrate within only a few hundred years. But, seeing how this decrease does not manifest itself, astronomers believe that the methane gas may actually be replenished from somewhere else on the planet. They argue that, otherwise, no such readings would have been visible on Mars for a very long time. They say that the main culprit behind the methane-destruction reaction is sunlight, which is known to produce a large number of reactions in the Red Planet's atmosphere.
What scientists want to learn at this point most of all is where the methane gas concentrations get replenished from. One possible theory had it that meteorites were responsible for the new amounts of methane. The thinking went that, as they passed through the atmosphere, the space rocks got heated, and then released the gas. But a new scientific paper shows that the idea is insufficient to explain all the new methane concentrations. Several hundreds of meteorites would have to go through the planet's atmosphere each sol (Martian day), to allow methane levels to be sustained through this individual source, Space Fellowship reports.
The new investigation was conducted by researchers at the Imperial College London (ICL), in the UK. They argue that another explanation that fails is that of an active volcano, although that would have probably been the easiest of the bunch. Therefore, only two more possible sources remain, the scientists say – microorganisms living in the Martian soil, or volcanic rock-water chemical reactions occurring naturally.
“Our experiments are helping to solve the mystery of methane on Mars. Meteorites vaporising in the atmosphere are a proposed methane source but when we recreate their fiery entry in the laboratory we get only small amounts of the gas. For Mars, meteorites fail the methane test,” ICL Department of Earth Science and Engineering Dr. Richard Court, study coauthor, says.
“This work is a big step forward. As Sherlock Holmes said, eliminate all other factors and the one that remains must be the truth. The list of possible sources of methane gas is getting smaller and excitingly, extraterrestrial life still remains an option. Ultimately the final test may have to be on Mars,” ICL Department of Earth Science and Engineering Professor Mark Sephton adds. He is also a coauthor of the new study detailing the finds. The work appears in the latest issue of the scientific journal Earth and Planetary Science Letters.
The new investigation, which was funded through a grant from the Science Technology Facilities Council (STFC), also determined that all the meteorites striking Mars' atmosphere each year were responsible for producing no more than ten kilograms of methane. On the other hand, the planet requires between 100 and 300 tonnes to replenish its original methane levels, which are depleted by sunlight-caused reactions.