LAST month, the world of planetary science blew up after the news that phosphine gas had been observed in Venus’s atmosphere, which could potentially be a sign of life.
The team that spotted the phosphine, led by Jane Greaves at Cardiff University in the UK, couldn’t find any mechanism for forming enough phosphine on Venus to account for these observations. On Earth, the gas is made by living organisms and industrial processes.
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Now, though, that detection has been called into question. First, a look at old data by a group that included researchers who worked on the latest phosphine study found no hints of the gas. Then a re-analysis of Greaves and her team’s observations by an independent group concluded that the measurements showed no signs of phosphine (see “More doubts cast on potential signs of life on Venus”). According to the scientists behind the second study, the original analysis may have introduced false signals into the data.
While this may seem like a disappointment – the idea of life on Venus is tantalising, but if there is no phosphine, there is no reason to suspect life exists there – it is actually an indication that science is progressing just as it ought to.
“The idea of life on Venus is tantalising, but if there is no phosphine, there is no reason to suspect life exists there”
An explosive claim – like that of a possible sign of life on a planet that seems crushingly inhospitable – must be evaluated through every means possible. For now, with many observatories closed due to covid-19, that means combing through information that scientists have already collected on Venus in order to look for clues.
So far, none of the observations are conclusive either way. There will surely be more studies in the coming weeks and months, and while they may continue to conflict with one another, they will eventually converge on an explanation. That is simply how science works: we can make predictions, but we must continue to examine all possible evidence until there is an answer.
Perhaps that answer will come when the observatories reopen – or maybe we will have to wait to send a spacecraft to Venus and and take a closer look.
