Science

Phosphine gas found on Venus suggests a ‘possible sign of life’

Mankind has often looked up at the night sky and wondered if we are alone in the universe. A recent discovery might just have found the answer to that age-old question in the clouds of Venus.

Conditions on Venus have always been dismissed as incompatible with life. Its surface is hot enough to melt lead. Its clouds are abundant in sulphuric acid. Its atmosphere has pressures up to 90 times that of the Earth. This all changed on the 14th of September when a study was released from an international team of scientists, led by Professor Jane Greaves from Cardiff University, detailing the discovery of a biomarker, phosphine gas, in the acidic clouds of Venus.

Greaves was inspired by famous astronomer Carl Sagan’s discovery that the pressure and temperature in Venus’ clouds reduce to habitable levels as altitude increases. Using the James Clerk Maxwell Telescope in Hawaii, Greaves and her team detected the absorption spectra of radio waves from Venus and identified the presence of phosphine gas. This discovery was further verified using the Atacama Large Millimetre Array in Chile.

Dr William Blain, biochemist and astrobiologist from the Massachusetts Institute of Technology, was enlisted to deduce the probability of the phosphine being a biological by-product. His team found that the production of phosphine would always consume energy. Therefore, this reaction is unlikely to occur spontaneously, nor could it be due to UV light breaking down molecules as the rate would be 10,000 times too slow to account for the amounts of gas detected. In an interview for The Sky at Night on the BBC, Blain said: “We just could not come up with any combination of sub-surface, on the surface, in the atmosphere, in the clouds, anything, that would explain the presence of phosphine”.

Despite the evidence seeming to point towards the presence of microbial life on Venus, there are still concerns around this conclusion. The amounts of sulphuric acid present in the clouds are incompatible with the biochemistry of all life we know of. There are only two ways that life could survive these conditions: either this life has a completely different biochemistry to what we see on Earth; or has a protective ‘armour’ which shields it within the acid droplets. The latter poses a few issues – how would they create this shield? Eat? Or exchange gases? Some forms of life on Earth have shown resistance to sulphuric acid, for example, succulents have a thin waxy layer which protects them from the acid, so this idea cannot be ruled out.

If these findings do mean there is life on Venus, not only do they answer the age-old question faced by mankind, it means that many planets, like Venus, that were ruled out in the search for habitable worlds could indeed harbour extraterrestrial life. Furthermore, if life has somehow managed to evolve independently on two neighbouring planets in our solar system, then it is surely more common in the universe than we ever could’ve imagined.


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13/10/2020

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Rosina Poller


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