What do fish bowels, swamps, and mounds of penguin dung all have in common? A noxious gas that may be the best evidence for extraterrestrial life. That’s according to researchers with MIT, which reports that smelly and flammable phosphine gas is produced by a type of life form that doesn’t require oxygen to live. These organisms, it turns out, are the only thing capable of producing the gas on rocky exoplanets, potentially making it easier to discover alien life.
According to a newly published study, phosphine can only be produced by anaerobic organisms (life that doesn’t need oxygen), meaning detecting this gas on other planets may be a sure sign that it contains alien life. Phosphine is referred to as a ‘pure biosignature,’ meaning its presence is a sign that a particular type of life form is also present — a kind that is substantially different from most living creatures on Earth.
Substantially high levels of phosphine produced on a planet would be detectable by telescopes like the James Webb Space Telescope over distances as long as 16 light-years, the study claims. Unlike oxygen, which is produced by many things other than life, the detection of phosphine on a different rocky planet (as opposed to gas giants) would essentially be the perfect proof of alien life.
The study’s lead author Clara Sousa-Silva has dedicated years of her life to investigating biosignature molecules that may help lead to the discovery of life on other planets, according to MIT. Of more than 16,000 candidates, phosphine stands out as unique and the team’s new study argues that the detection of this molecule on a rocky planet would mean that some type of anaerobic organism is present.
Extensive work went into evaluating whether it is possible for phosphorous to transform into detectable levels of phosphine through some method that doesn’t involve life…and the conclusion was that no, it is not possible. It is possible that other biosignatures pointing toward the existence of alien life will also be identified in the future, however.