Could there be alien life enveloping the planet Venus?
It's a possibility, according to scientists who say they've detected signs which could point to living organisms inside the atmosphere of our next-door planet.
An international team of astronomers, led by Professor Jane Greaves of Cardiff University, say they've discovered a gas in the clouds surrounding Venus which might be explained by the presence of organic life.
The study, published in the journal Nature Astronomy on Monday, shows the presence of phosphine - a molecule made up of one phosphorus atom and three hydrogen atoms.
On earth, this molecule is produced by microbes which are found in oxygen-poor environments such as swamps, as well as inside some animals.
The team, initially detected the phospine using the James Clerk Maxwell Telescope (JCMT) in Hawaii to detect the phosphine, following up with closer examination using the 45 telescopes of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.
Astronomers have speculated for decades that high clouds on Venus could offer a home for microbes – floating free of the planet's hot surface, but still needing to tolerate very high acidity. But actually discovering signs of them was still "a shock" to the experts.
Professor Greaves said: "This was an experiment made out of pure curiosity, really – 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!”
After confirming the presence of the gas, members of the team then attempted to work out how it could have been produced, to try and establish whether it was indeed caused by organic life.
The team believes their discovery is significant because they can rule out many alternative ways to make phosphine, but they acknowledge that confirming the presence of possible life needs "a lot more work". The high clouds of Venus are incredibly acidic – around 90% sulphuric acid – posing major issues for microbes to survive there.
Scientists from the team will appear on BBC Four's Sky At Night programme on Monday at 10.30pm to discuss the discovery.
