A few months after detecting an "unusually high" level of methane on Mars, researchers have yet to figure out what's causing the spike. They have, however, ruled out one possibility and appear to be getting closer to answering whether life exists on other planets.

According to a study published in Scientific Reports, researchers from Newcastle University in the U.K. have ruled out that the spike could have been caused by wind erosion of rocks that had trapped the methane from fluid inclusions and fractures on the Red Planet's surface.

"The questions are -- where is this methane coming from, and is the source biological? That's a massive question and to get to the answer we need to rule out lots of other factors first," principal investigator Dr. Jon Telling said in a statement.

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