Biosignature spotted on Venus could come from volcanoes, not life

A team of planetologists said that if there was phosphine on Venus, it could have geological effects …not organic—origins. Their findings suggest that phosphine, a chemical often associated with microbes, could come from a reaction in the Venusian sky triggered by volcanic eruptions on the planet’s surface.

Last year a scientist the debate has started when a team of scientists announced that they had phosphine detected, a gas that is produced by certain microorganisms and therefore considered to be a biosignature, in the atmosphere. Other studies immediately complicated this result, and earlier this year another team said the gas was not phosphine at all but sulfur dioxide. The team’s recent discoveries, published today in the Proceedings of the National Academy of Sciences, indicate that Venus may have active volcanoes, which planetary scientists have long been uncertain about.

The principle is this: the deep mantle of Venus could contain phosphorus compounds, called phosphides, which could be released into the atmosphere by the volcanoes of the planet in the form of volcanic dust. With sufficient explosive force – the researchers described the force needed as that of Earth’s Krakatoa or even the Yellowstone supervolcano – this dust could be hurled high into the planet’s cloudy sulfuric acid atmosphere. There, the phosphides would react with sulfuric acid to produce phosphine.

“Phosphine doesn’t tell us about the biology of Venus,” said Jonathan Lunine, a planetologist at Cornell University and co-author of the article, at a university. Press release. “It tells us about geology. Science points to a planet that has explosive volcanism active today or in the very recent past. “

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But the mystery of whether or not Venus has phosphine, and what may have produced it, is far from settled. “Unfortunately, I am not convinced by the latter argument,” said Clara Sousa-Silva, quantum astrochemist at the Center for Astrophysics | Harvard and Smithsonian, in an email. “The reaction of inorganic phosphides with concentrated sulfuric acid will not necessarily generate phosphine. ... A likely result of the reaction of phosphides with concentrated sulfuric acid would be an oxidation reaction and not the production of phosphine.

Sousa-Silva previous work examined atmospheres of Venus and other planets for potential signs of life like phosphine. She added, “We have known (and we have said it time and time again) that there are abiotic pathways for phosphine formation, including volcanism. It’s just that these routes are extremely rare and inefficient.

Venus tectonics are difficult to observe due to the planet’s dense atmosphere, which obscures its surface. The few images we have of the planet’s surface come from the Soviet Venera program of the 1970s and 1980s and radar scans taken by the Magellan Orbiter, which can pierce the cloud cover of Venus. The data from which Lunine’s team drew their conclusions was collected using the James Clerk Maxwell telescope on Mauna Kea and the ALMA telescope array in Chile. Some images collected by Magellan indicated geological features capable of explosive volcanism, the researchers said. Previously, The data European orbiter Venus Express has indicated that the planet may have active volcanoes.

Fortunately, three upcoming missions should tell us a lot more about this scorching planet. Around 2030, NASA’s DAVINCI + probe and the European Space Agency’s VERITAS orbiter and EnVision orbiter will all travel to Venus to study its atmospheric composition and surface tectonics, among other characteristics of our closest planetary neighbor. .

More: Why Venus Will Soon Be The Solar System’s Most Exciting Place