Mars, it appears, is belching a large amount of a gas that c ould be a sign of microbes living on the planet today.

In a measurement taken on Wednesday, NASA’s Curiosity rover discovered startlingly high amounts of methane in the Martian air, a gas that on Earth is usually produced by living things. The data arrived back on Earth on Thursday, and by Friday, scientists working on the mission were excitedly discussing the news, which has not yet been announced by NASA.

“Given this surprising result, we’ve reorganized the weekend to run a follow-up experiment,” Ashwin R. Vasavada , the project scientist for the mission, wrote to the science team in an email that was obtained by The Times .

The mission’s controllers on Earth sent new instructions to the rover on Friday to follow up on the readings, bumping previously planned science work. The results of these observations are expected back on the ground on Monday.