In my last post I wrote about a new hypothesis by Marc Fries of the NASA Johnson Space Center suggesting that Martian methane may have come from meteorite showers on the Red Planet. Well, not a week has passed, and already a paper refuting that hypothesis has been posted by Maarten Roos-Serote of the University of Michigan and colleagues.
The new study, whose co-authors include Chris Webster of the Jet Propulsion Lab and Paul Mahaffey of NASA’s Goddard Space Flight Center, used the entire database of Martian methane measurements, including some very recent, still unpublished data, as well as all published meteorite events on Mars. When all these data are considered, a connection between methane and meteor events is less evident. In addition, the authors used statistical analysis to show that there is no correlation between high atmospheric methane concentrations and the occurrence of meteor showers on Mars.
Although the Roos-Serote team acknowledges that methane could be produced by a meteoritic infall, the amounts are rather insignificant, and aren’t large enough to explain the observed methane peaks on Mars.
The new paper is a great example of how science works. A hypothesis is advanced, and as new data become available, gets tested. In this case, the new data set did not support the original idea, but refuted it. The only unusual thing here was that the refutation happened so fast. Sometimes that can take years or even decades.
Where does this leave Fries’ hypothesis? It is severely weakened, but for a final verdict we have to await more data. And in the meantime, we still have other proposed explanations for that mysterious Martian methane.