The possibility of life on Venus has been a source of fascination and debate for decades. In 2020, a team of researchers made headlines with their claim to have detected phosphine, a gas associated with life on Earth, in the clouds of our neighbouring planet. This discovery faced controversy, with subsequent observations failing to confirm the initial findings. However, the same team is now back with even stronger evidence, suggesting that phosphine is indeed present in Venus's clouds.
Presented at a Royal Astronomical Society meeting in Hull, England, the new data, collected using the James Clerk Maxwell Telescope in Hawaii, includes 140 times more information than the original observation. The researchers have also benefited from a new receiver installed on the telescope, adding to the confidence in their findings.
"What we've got so far indicates that we once again have phosphine detections," said Dave Clements, a reader in astrophysics at Imperial College London.
This discovery is further supported by independent research by a team led by Rakesh Mogul, a professor of chemistry and biochemistry at California State Polytechnic University, Pomona. Mogul reanalysed old data from NASA's Pioneer Venus Large Probe, which entered Venus's atmosphere in 1978. This data revealed the presence of phosphine in the planet's clouds at similar levels to those detected by Clements' team.
Adding to the intrigue, a separate team, which Clements is also a part of, has presented evidence of another gas, ammonia, in the atmosphere of Venus. This discovery is considered even more significant than the phosphine detection. While the presence of phosphine on Venus remains puzzling, ammonia is a gas known to be produced by microorganisms on Earth.
"If there is life on Venus producing ammonia, we do have an idea why it might be wanting to breathe ammonia," said Clements.
On Earth, ammonia, a pungent gas, is produced by bacteria during the decomposition of plant and animal waste. On Venus, ammonia could act as a buffer to the extreme acidity of the clouds, bringing it down to a level potentially survivable for some known earthly bacteria.
"It would make its environment much less acidic and much more survivable, to the point itâs only as acidic as some of the most extreme places on Earth â so not completely crazy," said Jane Greaves, a professor of astronomy at Cardiff University.
However, the scientists caution that the presence of phosphine and ammonia alone does not definitively prove the existence of life on Venus. More research is needed to understand the complex chemical processes occurring in the planet's atmosphere.
"There's a lot of other processes that could go on, and we just don't have any ground truth to say whether that process is possible or not," said Greaves.
Future missions to Venus, such as the Jupiter Icy Moons Explorer and NASA's DAVINCI, which is scheduled to launch in the early 2030s, are expected to provide invaluable data about the planet's atmosphere and could shed light on the mysteries surrounding these intriguing findings.
While the discovery of phosphine and ammonia on Venus is exciting, it is just the beginning of a longer journey to unravel the secrets of our closest planetary neighbour. The scientific community is eagerly awaiting further research to determine whether these gases are truly signs of life or merely products of unknown chemical processes. This new evidence keeps the possibility of life on Venus alive, adding a new chapter to the ongoing quest for extraterrestrial life.
