On Venus, the alleged phosphine is probably not one

According to one study, phosphine found in the Venusian atmosphere is probably the only common sulfur dioxide. Therefore, the “greatest scientific discovery in history” still has to wait.

In mid-September, a team Announced Venus discovered phosphine in the upper atmosphere. This statement made headlines. And for good reason, on our planet, we know that these molecules can be produced by anaerobic bacteria. From this statement, other studies have questioned the reliability of this possible identification. One of them, led by the University of Washington in collaboration with NASA researchers, Ends The so-called phosphine today is not … no.

A sign of sowing confusion

Each chemical compound absorbs the specific wavelengths of the electromagnetic spectrum. For example, astronomers analyze them to learn more about the chemical composition of the atmosphere. As part of its study, the first group announced Detection of a spectral signal of 266.94 GHz in the Venusian atmosphere.

Another compound that exists in Venus‌ is phosphine and sulfur dioxide, you should know that it absorbs radio waves close to this frequency, so question the researchers.

To separate the two compounds, the team conducted further observations with the Atacama Large Millimeter / Submillimeter Array or ALMA. Analyzes of ALMA observations at frequencies consistent only with sulfur dioxide led the team to this conclusion Sulfur dioxide levels on Venus are too low for the detected signal. Therefore, it should come from phosphine instead.

As part of this new study, researchers began by modeling conditions in the Venusian atmosphere based on decades of observations. They used this basis to comprehensively understand the features observed and unrecognized in ALMA data sets.

Ordinary sulfur dioxide

The team used this model to simulate the signals of phosphine and sulfur dioxide in the Venusian atmosphere at different levels and to analyze how the alma receives these signals in their configurations. Based on the signal shape, the researchers first pointed out that the absorption was not from the cloud layer of Venus as reported by the first team.

Instead, the observed signal Comes from the mesosphere of Venus, about 80 kilometers from the surface. However, at this altitude, harsh chemicals and ultraviolet radiation Phosphine destroys molecules in seconds According to researchers.

They found that there was also alma data Venus severely estimates the amount of sulfur dioxide in the atmosphere. “The configuration of the antenna of the ALMA during the 2019 observations had an unwanted side effect: it emits signals of gases, sulfur dioxide, which are found almost everywhere in the Venus atmosphere. Weaker than gases distributed in small quantities“Underlines NASA’s JPL’s Alex Akins. This phenomenon is called spectral line dilution.

In conclusion, the authors not only describe the observations made at the beginning of sulfur dioxide, but these results are more consistent with what astronomers know about the planet’s atmosphere, which includes acid clouds. Sulfuric. Finally, keep in mind that sulfur dioxide is not the third most common chemical compound in the Venusian atmosphere. Not considered a symbol of life.