Life on Venus? New Evidence Supports the Idea

 In late 2020, a group of scientists led by Jane Greaves at Cardiff University in Wales, U.K., reported finding the gas phosphine (PH3) in the clouds of Venus. This surprised many scientists. On Earth, phosphine has two known sources: a product of microbial decay of organic material or produced in a lab. The surface of Venus bakes at nearly 900 degrees. Thick clouds of sulfuric acid surround the planet. Scientists believe such conditions completely precluded the possibility of life on Venus.

Scientists argued that the discovery must be a mistake, and other researchers who looked for phosphine in Venus’ clouds could not immediately reproduce the discovery. A March 2021 study by Rakesh Mogul of Cal Poly Pomona did find phosphine there.

Still, the controversy raged among scientists. Even if phosphine did occur in the clouds of Venus, detractors said, there must be a geochemical process that creates it that did not involve living organisms.

Venus, credit NASA

Some scientists claim that volcanoes might be a source of phosphine on Venus, which is known to have active volcanoes. Sulfur dioxide in the clouds of Venus comes from volcanoes, but as Greaves says, “The amount of phosphine doesn’t change that much across the various observations. As a comparison, sulfur dioxide, which is believed to be related to volcanism on Venus, can vary wildly, more than 10 times from year to year, or even shorter timescales.”

By comparison, the phosphine varies only by a factor or two. “It is not really variable, and I think that’s important in the context of interpretations,” said Greaves. She adds that the observations come from multiple telescopes, making the observations more robust. As Greaves said, “We now have five detections over the last few years, from three different sets of instruments, and from many methods of processing the data. We’re getting a clue here that there is some steady source (of phosphine).”

As compelling as these observations are, there is still doubt in the minds of many scientists. Follow-up studies are needed, but finding even microbial life elsewhere would be a huge discovery.

 

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

 This is reprinted with permission from the Oklahoman and www.Oklahoman.com.