Molecule concentration may be the result of organic activity
An international group of astronomers announced on Monday (14) the presence of phosphine in the Venusian atmosphere. The study was published in the journal Nature Astronomy – British scientific journal specializing in scientific articles.
According to the research, on Earth, phosphine – or phosphorus hydride (PH3) – can only be found due to two processes: either by manufacturing industrially or by the action of microbes that develop in oxygen-free environments – called anaerobics . Using advanced telescopes, the team of astronomers from the United Kingdom, the United States and Japan was able to confirm the presence of the molecule on Venus. The first detection occurred by the James Clerk Maxwell Telescope (JCMT), operated by the East Asian Observatory in Hawaii.
“When we discovered the first signs of phosphine on the Venus spectrum, we were in shock!”, Said international team leader Jane Greaves, from Cardiff University, UK. To confirm the finding, 45 antennas from the Atacama Large Millimeter / submillimeter Array (ALMA) – an astronomical installation in Chile, of which ESO – European Southern Observatory – are partners.
The telescope, considered much more sensitive, found small concentrations of phosphine in the atmosphere of Venus, about 20 molecules per billion. Based on calculations, it was ruled out that the amount observed would be due to natural non-biological processes on the planet, such as sunlight, or the action of volcanoes and lightning, for example. In the case of these sources, a maximum of ten thousandths of the amount of phosphine identified on the planet would be created.
Since, according to the analysis, these processes would not be responsible for creating the amount of phosphine released, scientists then began to consider the possibility of a type of organism that could be the source of this biomarker. The team points out that on Earth, bacteria expel phosphine by removing phosphate from minerals or biological material, adding hydrogen. But any organism on the neighboring planet, the study points out, “will likely be very different from terrestrial cousins.”
Acidic atmosphere
Astronomers see this discovery as quite significant, but acknowledge a lot of work ahead to confirm the presence of “life”. That’s because the atmosphere of Venus is extremely acidic, with about 90% sulfuric acid, which would make it difficult for microbes to survive, says the European Southern Observatory.
This unknown is pointed out as a challenge by the team member, Clara Sousa Silva, from the Massachusetts Institute of Technology in the United States, who investigates the release of phosphine as a bio-signature of anaerobic life gas on planets that orbit other stars.
“Finding phosphine on Venus was an unexpected bonus. The discovery raises many questions, such as how the organisms can survive in the atmosphere of the neighboring planet. On Earth, some microbes can withstand up to 5% of acid in their environment – but the clouds of Venus are almost entirely made of acid ”, says the researcher.
Although the discovery raises expectations about the existence of life outside of Earth, ESO astronomer and ALMA’s European operations manager, Leonardo Testi, says the mission now is to investigate the chemical origin of phosphine. “It is essential to accompany this intriguing result with theoretical and observational studies to exclude the possibility that phosphine in rocky planets may also have a chemical origin different from that of Earth,” says Testi.
