Scientists stunned the world last yearthe ear claiming to have discovered traces of phosphine in the Venusian clouds. New research suggests this gas – which, interestingly, is produced by microbes“He wasn’t really responsible for the signal they detected.” Instead, it was probably sulfur dioxide, a not-so-exciting chemical.
Extraordinary research published in Nature in September last year is challenged by a set of papers to be published in The Astrophysical Journal, whose preprint is currently available at the archive. This is not the first work criticism the apparent discovery of phosphine on Venus and will probably not be the last.
That phosphine may be present on Venus was a revelation that blew our minds because living organisms are one of the only known sources of stinking gas. The team responsible for the apparent discovery, led by Cardiff University astronomer Jane Greaves, found evidence in spectral signals collected by two radio antennas: the James Clerk Maxwell Telescope (JCMT) and the Atacama Large Millimeter / Submillimeter Array (ALMA). Spectral lines at certain wavelengths indicate the presence of specific chemicals and, in this case, involved the presence of phosphine in the Venusian cloud layer.
The authors of the Nature study did not claim that life exists on Venus. Rather, they asked the scientific community to explain their rather bizarre observation. Indeed, it was an exceptional statement, as it suggested that Venus – one of the most inhospitable planets in the solar system – could actually be habitable, with microscopic organisms floating through the clouds.
Unfortunately, this does not seem to be the case.
“Instead of phosphine in the clouds of Venus, the data are consistent with an alternative hypothesis: they detected sulfur dioxide,” said Victoria Meadows, co-author of the new study and professor of astronomy at the University of Washington. statement. “Sulfur dioxide is the third most common chemical compound in the atmosphere of Venus and is not considered a sign of life.”
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Meadows, along with researchers from NASA, the Georgia Institute of Technology and the University of California, Riverside, came to this conclusion by modeling conditions in the Venusian atmosphere, which they did to reinterpret the radio data collected by the original team.
“This is what is known as the radiative transfer model and incorporates data from observations of Venus from several decades from several sources, including observatories here on Earth and spacecraft missions such as Venus Express,” said Andrew Lincowski. researcher at the UW Department of Astronomy and lead author of the paper, in the statement.
Equipped with the model, the researchers simulated the spectral lines produced by phosphine and sulfur at several atmospheric altitudes on Venus, as well as how these signatures were received by ALMA and JCMT. The results showed that the shape of the signal, detected at 266.94 gigahertz, probably came from the Venusian mesosphere – an extreme height where sulfur dioxide may exist, but phosphine cannot because of the harsh conditions there, according to research. In fact, this environment is so extreme that phosphine would not last more than a few seconds.
According to the authors, the original researchers underestimated the amount of sulfur dioxide in the Venusian atmosphere and instead attributed the 266.94 gigahertz signal to phosphine (both phosphine and sulfur dioxide absorb radio waves around this frequency). This happened, according to the researchers, due to an “unwanted side effect” known as spectral line dilution, explained the study’s co-author and NASA JPL scientist Alex Akins.
“They deduced a low detection of sulfur dioxide due to it [an] weak artificial signal from ALMA “, added Lincowski. “But our modeling suggests that the ALMA data diluted in-line would still have been consistent with typical or even large amounts of Venus sulfur dioxide, which could fully explain the observed JCMT signal.”
This new result could be devastating for Nature and it will be interesting to find out how the authors react to this latest criticism. That being said, some scientists believe that the writing is already on the wall or, more precisely, in the trash.
“Soon after the publication of the original paper, we and others had strong doubts about their analysis,” Ignas Snellen, a professor at Leiden University, wrote in an e-mail. “Now, I personally believe that this is the final nail in the coffin of the phosphine hypothesis. Of course, it can never be proven that Venus is completely phosphine-free, but at least now there is no other evidence to suggest otherwise. I’m sure others will keep looking though. ”
In December, Snellen and colleagues challenged the Nature study, arguing that the method used by the Greaves team led to a “false” high signal-to-noise ratio and that “there is no statistical evidence” for phosphine on Venus.
The apparent absence of phosphine on Venus, and therefore the absence of any evidence of microbial life, is much less interesting than the opposite, but this is sometimes the case. Science does not make claims or promises about the interests of all things, and we, as defenders of the scientific method, must come to accept our ongoing universe as we find it.