A few months after detecting an "unusually high" level of methane on Mars, researchers have yet to figure out what's causing the spike. 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?" principal investigator Dr. Jon Telling said Telling added that over the last decade, winds on Mars have...