A UK-led team of astronomers has discovered a rare molecule – phosphine – in the clouds of Venus, pointing to the possibility of extra-terrestrial ‘aerial’ life.
Hints of life discovered on Venus
stronomers have speculated for decades that high clouds on Venus could offer a home for microbes – floating free of the scorching surface, but tolerating very high acidity. The detection of phosphine molecules, which consist of hydrogen and phosphorus, is an important step in the search for life beyond Earth, a key question in science. The results are reported in the journal Nature Astronomy.
The discovery was made by Professor Jane Greaves while she was a visitor at the University of Cambridge’s Institute of Astronomy. Greaves and her collaborators used the James Clerk Maxwell Telescope (JCMT) in Hawaii to detect the phosphine, and followed up their discovery on the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Both facilities observe Venus at a wavelength of about 1 millimetre, much longer than the human eye can see.
“This was an experiment made out of pure curiosity, really – taking advantage of JCMT’s powerful technology, and thinking about future instruments,” said Greaves, who is based at Cardiff University. “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!”
Luckily, conditions were good at ALMA for follow-up observations while Venus was at a suitable angle to Earth. Processing the data was challenging, however, as ALMA isn’t usually looking for subtle effects in bright objects like Venus.
“In the end, we found that both observatories had seen the same thing – faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below,” said Greaves.
Image: Synthesized false colour image of Venus
Credit: JAXA / ISAS / Akatsuki Project Team
Reproduced courtesy of the University of Cambridge
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