The search for full-blown extraterrestrial civilizations may have a long road ahead, but if we dial things back a bit, there’s now some intriguing news regarding microbial life on a planet right here in the Solar System.
As EarthSky reports, new research published in Nature Astronomy indicates that the atmosphere of Venus contains unexpected amounts of phosphine gas — something that is, on Earth, considered a “conclusive biosignature,” a sign of life.
While Venus as a whole is considered inhospitable, with extreme surface temperatures capable of melting lead, the higher areas of its atmosphere, or the high cloud decks, are much more Earth-like and considered potentially habitable (though still highly acidic).
Professor Jane Greaves of Cardiff University led the research. Using the James Clerk Maxwell Telescope in Hawaii and the Atacama Large Millimeter Array observatory in Chile, the team analyzed the composition of that higher atmosphere, and that’s where they found the phosphine.
“This was an experiment made out of pure curiosity, really,” Professor Greaves said of their work, “taking advantage of JCMT’s powerful technology, and thinking about future instruments. I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus’ spectrum, it was a shock!”
Phosphine only appears under two known conditions: In a lab, or as the result of microbes that live in oxygen-free environments. This leaves two possibilities for the researchers: Either there are other, as-yet-unknown processes that can result in the creation of phosphine on rocky planets, or the phosphine on Venus is truly indicative of microbial life.
The researchers wrecked their brains trying to come up with possible explanations, as the Royal Astronomical Society states in their announcement. However, they still couldn’t come up with a satisfactory explanation for the amount of phosphine they’ve observed:
“Massachusetts Institute of Technology scientist Dr William Bains led the work on assessing natural ways to make phosphine. Some ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough of it. Natural sources were found to make at most one ten thousandth of the amount of phosphine that the telescopes saw.”
The next step for the researchers will be observing Venus even harder, looking for any other signs of life, which may include other gases.
An intriguing paper about chemistry on Venus was published today. @NASA was not involved in the research & cannot comment directly on the findings; however, we trust in the scientific peer review process & look forward to the robust discussion that will follow its publication. https://t.co/uA0QztrAnV
— Thomas Zurbuchen (@Dr_ThomasZ) September 14, 2020
One of the more compelling possibilities is that the phosphine may actually be a sign of remnants of life that once existed on Venus billions of years ago, when scientists believe the planet was much more like Earth. While its surface is no longer hospitable, some microbes may have survived in that habitable zone in the atmosphere.