Well, well, well. Yet more proof that, if nothing else, the universe has a deep and savage sense of irony. “Swamp gas” went from a dismissive write-off of UFO encounters to a ubiquitous running joke among the UFO community and public at large. Even if you know absolutely nothing about UFOs you know they’re all either balloons or swamp gas. Now a new study has found that phosphine, the toxic chemical that makes swamp gas so nasty, is a definite indicator of anaerobic life (life that doesn’t use oxygen) and could be one of the best signs of extraterrestrial life. It all comes full circle, eventually.
Phosphine is a foul-smelling, highly flammable, and generally unpleasant toxic gas found in dung piles and in putrid bogs and swamps. It might also be the best biosignature of alien life. According to a press release from MIT, researchers found that there are only two ways phosphine can be produced. In the intensely high-pressure storm systems of gas giants like Jupiter and Saturn, and by anaerobic life. According to the researchers, finding phosphine on a rocky alien planet would be a definite indicator that there was life there.
Lead author of the new paper, MIT researcher Clara Sousa-Silva says:
“Here on Earth, oxygen is a really impressive sign of life. But other things besides life make oxygen too. It’s important to consider stranger molecules that might not be made as often, but if you do find them on another planet, there’s only one explanation.”
Clara Sousa-Silva and colleagues at MIT have amassed a database of over 16,000 possible alien biosignatures. Most of these biosignatures are unreliable and could be the byproduct of other forces besides life. But Sousa-Silva has spent the last 10 years studying phosphine in particular, and now concludes that phosphine would be a definite indicator of life.
Phosphine was discovered in the atmospheres of Jupiter and Saturn in the 1970s. Due to its composite elements, phosphine is a molecule that won’t come together by chance except in the high-energy, high-pressure, violent storms that swirl through gas giants.
Sousa-Silva wondered if phosphine was could be produced here on Earth, specifically by life on Earth. Sousa-Silva says:
“So we started collecting every single mention of phosphine being detected anywhere on Earth, and it turns out that anywhere where there’s no oxygen has phosphine, like swamps and marshlands and lake sediments and the farts and intestines of everything. Suddenly this all made sense: It’s a really toxic molecule for anything that likes oxygen. But for life that doesn’t like oxygen, it seems to be a very useful molecule.”
Sousa-Silva and her team spent the last several years trying to figure out if anything besides life can create phosphine. They found that, on a rocky planet like Earth, there are no forces powerful enough to create the molecule besides life. She says:
“At some point we were looking at increasingly less-plausible mechanisms, like if tectonic plates were rubbing against each other, could you get a plasma spark that generated phosphine? Or if lightning hit somewhere that had phosphorous, or a meteor had a phosphorous content, could it generate an impact to make phosphine? And we went through several years of this process to figure out that nothing else but life makes detectable amounts of phosphine.”
Sousa-Silva and her team determined that if phosphine was produced by alien life on some faraway rock, it would be detectable even if it was at the quantities produced here on Earth. That means that although phosphine is an indicator of anaerobic life, detecting it may lead researchers to an alien ecosystem as varied as ours. Or at least a big swamp.
Now the real question is when UFO and alien sightings were first being dismissed as swamp gas, were they really being dismissed? What if the aliens have actually been swamp gas this whole time.