A new analysis hints that there may not be much phosphine on Venus after all. September鈥檚 announcement of observations of phosphine gas in the Venusian atmosphere sparked excitement because of the possibility that it could have come from life. But researchers digging through archive data have placed a stringent limit on how much of the unexpected gas is actually there.
After the original detection, Clara Sousa-Silva at the Harvard-Smithsonian Center for Astrophysics in Massachusetts 鈥� who was also involved in the research announced in September 鈥� and her colleagues examined data collected in 2015 at Maunakea Observatories in Hawaii. The observations they looked at were taken in infrared wavelengths, where we would expect to see signs of phosphine.
They found no hint of the gas. The original observations discovered phosphine at concentrations of about 20 parts per billion, but this research team placed a limit at about 5 parts per billion.
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鈥淚s it because there鈥檚 no phosphine? That is possible, but then we have to try to figure out where the interpretation of the original data went wrong,鈥� says Sousa-Silva.
It is also possible, though, that this is a clue as to phosphine鈥檚 distribution in Venus鈥檚 atmosphere. The gas is expected to be quickly destroyed in many parts of the atmosphere, particularly at the cloud tops, which is where the infrared readings were taken. So it is possible these measurements simply didn鈥檛 probe deeply enough to spot the phosphine, says Sousa-Silva.
It is also possible that the abundance of phosphine across the planet varies over time. 鈥淚f the phosphine came from life, we would expect enormous local variability,鈥� says Sousa-Silva. 鈥淥n Earth, where it does come from living organisms, it鈥檚 extremely variable. In most of the atmosphere, there鈥檚 almost none of it, but above the places where it鈥檚 being created, there鈥檚 much more.鈥�
Overall, these conflicting measurements demonstrate that we need far more observations of Venus in many different wavelengths to try to probe a greater number of different areas of the atmosphere, says Sousa-Silva. 鈥淭his isn鈥檛 a big gotcha,鈥� she says. 鈥淚t鈥檚 really interesting and it tells us a lot about what we have to do for future work.鈥�
We may not be able to figure out what the hints of phosphine mean until we send a spacecraft to take measurements from up close, says Paul Byrne at North Carolina State University. 鈥淲e just don鈥檛 know enough about Venus to know what this really means,鈥� he says. 鈥淯ntil, and if, we get a spacecraft to Venus, we鈥檙e kind of tilting at windmills a little bit in trying to find an answer to these questions.鈥�
搁别蹿别谤别苍肠别:听
