In two papers published on Monday, a team of astronomers announced that they had detected significant levels of phosphine gas in the atmosphere of Venus. While certainties are rare in science, and in astronomy especially, phosphine is most commonly created by the decomposition of organic life. The high levels of phosphine, thousands of times greater than the percentage in Earth’s atmosphere, therefore strongly suggest the presence of microbial life in the Venusian clouds.
The discovery is especially remarkable given the truly terrifying conditions Venus has to offer. The roughly Earth-sized planet boasts temperatures of more than 800 degrees Fahrenheit year round, atmospheric pressure equivalent to that experienced by divers 3,000 feet beneath Earth’s oceans, and omnipresent clouds of sulfuric acid famous for eating NASA probes. For this reason Venus has often been ignored as a possible candidate for hosting extraterrestrial life, with scientists turning to Europa and Enceladus in a search for more Earth like environments where, it was believed, life would be more likely to flourish.
If there is life on Venus it would likely not be anything like the aliens of our sci-fi movies, both in its complexity and in its strangeness. It would be astonishingly difficult, and likely impossible, for anything big enough to be visible to the naked eye to evolve in those conditions. However, whatever is causing those phosphine emissions would also be shockingly alien, in the literal sense of the word, as it would have to be tougher than refined metal to survive.
Even extreme environments on Earth, such as the Marianas Trench, are not close to as deadly to the regions of Venus where these signatures have been detected. To survive there, alien microbes would have to have evolved truly astonishing adaptations that are hard to even imagine. They may not even be Carbon-based, instead using another element like Silicon to build DNA structures that could survive the harsh conditions. In fact, they may not even have DNA.
Every example of life scientists have ever had the opportunity to study has come from the planet Earth, and despite the astonishing diversity of environments on this planet when trying to imagine a truly alien organism our models simply do not apply. We can speculate how these alien bacteria might evolve, but we cannot truly know until a probe is able to obtain a sample.
That may prove difficult, however, as the Venusian atmosphere is so deadly only two probes have ever managed to capture images of the planet’s surface before imploding. At the time of this writing only one human craft is engaged in studying Venus, a Japanese probe named Akatsuki, and that ship is only imaging from orbit.
Scientists may have been able to detect the likely presence of life, but actually studying it will require incredible technological leaps on the part of humanity. Whether or not those missions will receive funding remains to be seen, especially as there are already scientists voicing their doubts about the results of this study.
There are other possible causes for phosphine emissions that have nothing to do with organic life, and while the authors of the paper claim to have ruled out all other possibilities several scientists have called the results premature.
Nevertheless, the results are incredibly exciting and as scientists continue to pore over and discuss the data the internet will no doubt take the chance to celebrate. In a year so filled with disheartening news, the discovery of alien life, life that can survive in the face of seemingly insurmountable obstacles, is certainly welcome.