It's been a while, but Martian methane is back. NASA's Curiosity rover detected rich amounts of methane in the planet's air on Wednesday, reigniting hope of life on Mars, the New York Times reports. "Given this surprising result, we've reorganized the weekend to run a follow-up experiment," a NASA project scientist wrote his team after the data reached Earth on Thursday. Now Curiosity is sidelining other scientific work to seek more methane, which could be a sign of life. Scientists know the gas was emitted fairly recently—after all, chemical reactions and sunlight break down its molecules over a few hundred years—but they don't know if living microbes released the methane or if it had been trapped underground for millions of years.
A European orbiting spacecraft first detected Mars methane 15 years ago, but that finding wasn't repeated until Curiosity reached Mars in 2012 and detected the gas in 2013. That methane was only up to 7 parts per billion; Wednesday's find was three times as rich at 21 parts per billion. Curiosity noticed the gas right after crossing a 96-mile-wide depression called the Gale Crater, which scientists have linked to Martian methane before, per Scientific American. While the gas may not signify life, it could help future colonizers "as certain types of microbes can use methane as a source of carbon and energy," scientist Marco Giuranna tells AFP. He says preliminary results should be available next week. (Read more Mars stories.)