[ad_1]
The discovery of phosphine gas in the clouds of Venus could possibly indicate signs of life on the planet, scientists have said.
The gas has been detected in Venus’ atmosphere, suggesting that the planet could harbor unknown photochemical or geochemical processes.
On Earth, phosphine, a colorless gas that smells like decaying garlic or fish, is produced predominantly from anaerobic biological sources.
Small amounts of gas are produced naturally from the decomposition of organic matter.
While conditions on the surface of Venus, the second planet from the Sun, are hostile to life, the environment of its upper cloud layer, about 53-62 km (33-38 miles) above the surface, is temperate. .
But according to the study, published in Nature Astronomy, the composition of the clouds is very acidic and, under such conditions, phosphine would be destroyed very quickly.
Jane Greaves of Cardiff University in the UK and her colleagues observed Venus in 2017 and 2019.
They detected a spectral signature that is unique to phosphine and estimated an abundance of 20 parts per billion of phosphine in the clouds of Venus.
The researchers looked at different ways the gas could have been produced, including from sources on the planet’s surface, micrometeorites, lightning, or chemical processes that occur within clouds.
But they could not determine the source of the phosphine traces.
However, they argue that the detection of phosphine is not strong evidence of microbial life and only indicates potentially unknown geological or chemical processes occurring on the planet.
They say more observations and models are needed to explore the origin of gas in the planet’s atmosphere.
Writing in the article, they say: “PH3 (phosphine) could originate from an unknown photochemistry or geochemistry, or, by analogy with the biological production of PH3 on Earth, from the presence of life.”
They add: “If no known chemical process can explain PH3 within the upper atmosphere of Venus, then it must be produced by a process that was previously not considered plausible for conditions on Venus.
“This could be unknown photochemistry or geochemistry, or possibly life.”
The researchers continue: “Even if confirmed, we emphasize that the detection of PH3 is not strong evidence for life, only for abnormal and unexplained chemistry.
“There are substantial conceptual problems for the idea of life in the clouds of Venus: the environment is extremely dehydrating and hyperacidic.
“However, we have ruled out many chemical pathways to PH3, with the most likely ones falling short by four to eight orders of magnitude.
“To further discriminate between unknown photochemical and / or geological processes such as the source of Venus’s PH3, or to determine if there is life in the clouds of Venus, substantial modeling and experimentation will be important.
“Ultimately, a solution could come from revisiting Venus for in situ measurements or aerosol return.”
Associate Professor Alan Duffy, an astronomer at Swinburne University and a senior scientist at the Royal Institution of Australia, said: “This is one of the most exciting signs of the possible presence of life beyond Earth that I have ever seen, and certainly the most amazing location you could imagine.
“Our twin planet Venus is a hellish world. While the surface is hot enough to melt lead, the temperature drops as you go through the clouds, becoming similar to Earth in temperature and pressure at an altitude of 50 km, exactly where the phosphine was found.
“While the temperature is benign, the clouds contain sulfuric acid which should break down the phosphine, so something is forming it again, and since phosphine is associated with life on Earth, it is tempting to think that it could be life on Earth. Venus.
“But before we can be more confident in that, we have to rule out all other possible non-biological means of producing it.”
[ad_2]