The discovery of Phosphine in the clouds around venus in september 2020 left the world wondering what could explain its presence.Phosphine might even mean life, as there’s no process to explain why it would exist on this planet. Following the discovery, a team of researchers worldwide are now investigating whether this is the start of a new chapter in astrochemistry or even exobiology or simply a data artefact.

Phosphine(PH3) is a pyramid shaped molecule with a single phosphorus atom on top, and a base formed of three hydrogen atoms. It is the simplest gas that has phosphorus on it, the phosphorus equivalent of ammonia(for nitrogen), methan (for carbon), and water(for oxygen).

Structure of PH3

Phosphine(PH3) is found here on Earth. as well as on the solar system’s gas giants. Deep within Jupiter and Saturn , high temperature and extreme pressure combine to create phosphine spontaneously. The reducing atmosphere of these giant planets means this compound can not only form, but also persists. On Earth, However, phosphine is a byproduct of the decomposition of origin matter humanity also synthesizes for use in the semiconductor and plastic industries. Given the oxidising atmosphere found on many rocky planets, Such as Earth, phosphine quickly breaks down, but is replenished by organic processes. This has led astrochemists to conclude that phosphine could be a proxy for life as its synthesis Via. Other Processes on rocky planets are considered unlikely. That is why atmosphere of Venus by a team of scientists led by Jane Greaves.

Why is Phosphine Special ?

There are many molecules associated with life, such as methane , water or oxygen. If we detect these molecules on habitable planets, it could mean we found life or not. These molecules have false positives; geological or photochemical processes that can produce them without the intervention of life phosphine does not. "I found that, if detected on a rocky planet, Phosphine can only mean life". - Clara sousa silva.

Chemical Fingerprint

"If the Phosphine detection is real, either we don't understand Phosphorus or Phosphine chemistry and Venus's atmosphere, or there's some life. It's intriguing". - David Rothery Professor of planetary geoscience at the Open university, who was not involved in the study.

Greaves Team analysed data from the Atacama Large Millimetre/ Submillimetre Array( alma) telescope and the James Clerk Maxwell Telescope( JCMT). Both telescopes observed emissions from Venus’s atmosphere at a wavelength of about 1 mm, identifying the fingerprint of a number of molecules. The team discovered Phosphine at a level approaching 7ppb throughout the mesosphere of the planet. Multiple tests confirmed that the signal was phosphine and not any other molecule.

Rakesh Mogul, a professor of biological chemistry at california state polytechnic, Pomona, was intrigued by the these result.” It seemed a little controversial, because PH3 is not the most stable of molecules and Venus's atmosphere is considered to be mostly oxidative. So, phosphine should not survive in that atmosphere very long and it should not be detected by remote observation", he says. Mogul and his team used different dataset, However, to assess whether there was indeed phosphine in Venus’s clouds- one that’s over 40 year old.

Greaves and her team have already examined the new data. In another preprint, her team reported that the republished data suggests a weaker phosphine signal. Instead of 7ppb just 1ppb. The researchers, though, still consider this finding ‘reasonably secure’.

So, is there Phosphine on Venus or not? The simplest answer, scientists say, “it’s just too soon to tell”.

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