In such worlds, “as far as we can tell, only life can make phosphine,” said Dr. Sousa-Silva. She has long studied the gas theory that finding that it emits from rocky planets orbiting distant stars may be evidence that life exists elsewhere in the Milky Way.
Here on Earth, phosphine is found in our intestines, in the feces of badgers and penguins, and in some deep-sea worms, as well as in other biological environments associated with anaerobic organisms. It is also extremely poisonous. The military used it for chemical warfare and used it as a fumigant on farms. In the TV show “Breaking Bad”, the main character Walter White makes him kill two rivals.
“There’s not much understanding of where it comes from, how it’s formed, things like that,” said Matthew Pasek, a geologist at the University of South Florida in Tampa. “We’ve seen it related to where the microbes are, but we haven’t seen microbes do it, which is a barely noticeable difference, but important.”
Dr. Souza-Silva was surprised when Dr. Greaves said she had discovered phosphine.
“This moment plays a lot in my mind because I took a few minutes to think about what was happening,” she said.
If there really was a phosphine on Venus, she believed there could be no other obvious explanation than anaerobic life.
“What we find in circumstances also makes full sense with what we know thermodynamically,” she said.
The team needed a more powerful telescope, and scientists then used the large millimeter Atacama array in Chile in March 2019.