Martian methane—spotted in 2004—has mysteriously vanished.
https://www.sciencemag.org/news/2018/12/martian-methane-spotted-2004-has-mysteriously-vanished
Source: By Paul Voosen, Science Magazine.
Excerpt: Scientists first detected traces of [methane]—a critical indicator of life on Earth—in the planet’s atmosphere decades ago. But today, researchers reported that a European satellite hasn’t spotted a single trace of methane. The finding, if it holds up, could complicate scientific dreams that martian microbes might be spewing the gas in the planet’s subsurface. ...scientists suspect that hundreds of tons of organic carbon pour into the martian atmosphere each year from solar system dust, reacting with solar radiation to form methane, say John Moores, a planetary scientist at York University in Toronto, Canada. “Where is all that carbon going?”...
Source: By Paul Voosen, Science Magazine.
Excerpt: Scientists first detected traces of [methane]—a critical indicator of life on Earth—in the planet’s atmosphere decades ago. But today, researchers reported that a European satellite hasn’t spotted a single trace of methane. The finding, if it holds up, could complicate scientific dreams that martian microbes might be spewing the gas in the planet’s subsurface. ...scientists suspect that hundreds of tons of organic carbon pour into the martian atmosphere each year from solar system dust, reacting with solar radiation to form methane, say John Moores, a planetary scientist at York University in Toronto, Canada. “Where is all that carbon going?”...