If life does exist on Venus, NASA may have detected it some 42 years ago. In recent weeks interest in life on Venus has renewed after scientists discovered traces of phosphine – a toxic gas long proposed as a possible sign of microbial life – in the upper part of the planet’s thick atmosphere, published in the Nature Astronomy journal. It was a landmark moment in the hunt for life elsewhere, a project that has been largely focused on Mars and a select few moons orbiting Jupiter and Saturn.
Hot and poisonous, chances of Venus being a place where alien life could exist had been concluded: zero.
However, with the hook of the new find, biochemist Dr Rakesh Mogul decided to sift through the NASA archives.
It was here that he claimed to have found evidence that suggests researchers in 1978 also detected traces of phosphine on Venus.
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He told LiveScience: “When the Nature Astronomy paper came out, I immediately thought of the legacy mass spectra.”
Dr Mogul said he and his team of researchers were broadly familiar with the data from the missions.
He added: “So, for us, it was a natural next step to give the data another look.
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“As such, after consulting with my co-authors, we identified the original scientific articles, and promptly started looking for phosphorous compounds.”
The discovery, published to the arXiv database last month, has not yet been peer-reviewed.
It doesn’t tell researchers much beyond what was reported in Nature Astronomy.
The researchers, however, said the data makes the presence of phosphine even more certain.
The 1978 figures comes from the Large Probe Neutral Mass Spectrometer (LNMS), one of several instruments that descended into Venus’ atmosphere as part of the Pioneer 13 mission.
Suspended from a parachute, Pioneer 13 dropped a large probe into Venus’ clouds.
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Data was then collected and beamed back to Earth as the probe plummeted to its death.
Samples were placed through mass spectrometry – a standard laboratory technique used to identify unknown chemicals.
At the time, researchers focused on other chemicals found in the sample, glossing over phosphorus-based compounds like phosphine.
When Dr Mogul’s team reexamined the LNMS data they found signals that resemble phosphine and other phosphorus-based compounds.
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However, LNMS wasn’t built to sniff out phosphine-like compounds.
It would therefore have had a hard time separating the gas from other molecules that have similar masses.
Dr Mogul said: “I believe that evidence for trace chemicals that could be signatures of life in the legacy data were sort of discounted because it was thought that they could not exist in the atmosphere.
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“I think many people are now revisiting the notion of Venus as a fully oxidising environment.”
Dr Mogul and his colleagues also found hints of other chemicals that shouldn’t arise naturally in Venus’ clouds — substances like chlorine, oxygen and hydrogen peroxide.
He wrote: ”We believe this to be an indication of chemistries not yet discovered and/or chemistries potentially favourable for life.”
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