Earth may no longer be the sole planet in the solar system where life occurs. An international team of scientists uncovered substantial evidence of microbial life in the clouds of Venus in the form of an uncommon molecule known as phosphine.

The clouds of Venus can actually reach pleasant temperatures of 30 degrees Celsius - Image Credit: Jurik Peter via Shutterstock / HDR tune by Unviersal-Sci

On Earth, phosphine is solely created industrially or by microbes that flourish in environments with no oxygen. The idea of life on Venus is nothing new; scientists have speculated for decades that its clouds might provide habitation to free-floating microbes, at a safe distance from the searingly hot surface. Although one potential issue to overcome in these environments is that life needs to be able to tolerate strong acidity. Interestingly enough, the discovery of phosphine might point to such extraterrestrial life.

In an ESO press release, professor Jane Greaves, head of the research team, stated that the team was in absolute shock when they received the first hints of phosphine in the spectrum of our sister planet. The compound is predicted to be very rare though, with only a single estimated part per billion in Venus' atmosphere.

Initially, the scientist speculated that perhaps volcanoes, sunlight, or lightning could account for the presence of the rare molecule. However, when subsequent calculations were run to determine whether these amounts could originate from non-biological processes on the planet, the baffling answer was: no. It turns out that non-biological sources could only account for, at most, one ten-thousandth(!) of the amount of phosphine that the scientists observed.

The Phosphine was detected in Venus’ clouds - Image Credit: ESO/M. Kornmesser/L. Calçada & NASA/JPL/Caltech

To produce the observed amount of phosphine (consisting of phosphorus and hydrogen) on Venus, organisms akin to those found on Earth would only need to operate at about 10% of their maximum productivity. Bacteria on Earth are known to produce phosphine: they take up phosphate from minerals or biological material, add hydrogen, and ultimately expel phosphine. Organisms on Venus will presumably be quite different from their equivalents on Earth; however, they could very well be the origin of phosphine in this extraterrestrial atmosphere.

A particular challenge for life remains, although temperatures in Venus' atmosphere can reach an agreeable 30 degrees Celcius, its high acidity will offer a significant hindrance for possible life to survive there. As research team member Clare Sousa Silva stated: 'On Earth, some microbes can cope with up to about 5% of acid in their environment, but the clouds of Venus are almost entirely made of acid.'

The astronomers made their discovery by use of the James Clerk Maxwell Telescope located in Hawaii. Subsequently confirming their findings required utilizing 45 antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) located in Chile, a more sensitive telescope. Both facilities observed Venus at a wavelength of about 1 millimeter, much longer than the human eye can see; only telescopes at a high enough altitude can identify it effectively.

Although indisputably establishing the presence of life on solar system neighbor Venus still requires a great deal of work, the research team is confident in the significance of their discovery as they managed to rule out many of the alternative explanations. The team published their findings in the science journal: Nature.

All in all, we, for one, can't wait to see what further research on this fascinating discovery will bring!

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