Traces of life found on Venus
The gas monophospan (PH3), which was first detected on Venus, suggests that our neighbouring planet could be home to life.
Venus is one with a temperature of over 450 degrees on the hostile planet of our solar system. In theory, according to some studies, there could have been oceans and even life on the celestial body 700 million years ago. Scientists from the University of Wisconsin-Madison also proposed in 2018 that the Venus clouds could still contain life. However, this has not yet been confirmed by a NASA expedition.
Scientists from Cambridge and Cardiff Universities have now found further evidence of life on our neighbouring planet. According to Jane Greaves, this is the poisonous gas monophospan (PH3), which was first detected in the clouds of Venus. On earth, the gas, also known as phosphine, is used in the chemical industry and as a poison for pest control. Anaerobic bacteria also generate the gas in small quantities naturally, which means that the earth's atmosphere contains a few molecules per trillion air molecules (parts per trillion, ppt) monophospan (PH3). The phosphine is always produced due to human activity and microbial life.
Spectral data show Monophospan (PH3) on Venus
The scientists have verified the gas on the basis of spectral data that they recorded in 2017 with the James Clerk Maxwell radio telescope and in 2019 with the Atacama Large Millimeter / submillimeter Array (ALMA). Greaves explains that the scientists “could not find any other chemical compound besides phosphine that could explain the characteristics we observed.” The clouds of Venus thus contain small amounts of monophospan (PH3).
The measured concentration of 20 molecules per billion gas particles (parts per billion, ppb) is extremely low, but according to Greaves "even the presence of these small proportions of phosphine is completely unexpected for an oxidized atmosphere like that of Venus." Phosphorus on Venus actually only exist in its oxidized form.
Sources for Monophospan (PH3) on Venus
According to the research published in the journal Nature Astronomy, there must be an active source for Monophospan on Venus because the gas envelope is chemically degraded in a continuous process and the gas can therefore last for a maximum of 1,000 years. According to Greaves, “there must therefore be a source in the atmosphere, on the surface or below that provides a supply of phosphorus.” However, the scientists rule out a chemical reaction that generates enough monophosphate for the measured concentration.
The researchers, therefore, state that “if no known process can explain the phosphine in the atmosphere of Venus, then it must be produced by a process previously not assumed to be plausible on Venus.” It could be “unknown photochemistry or geochemistry but also about life. "