According to a research published in the journal Nature Astronomy on September 14, 2020, there is potential sign of life on the much-overlooked planet Venus. The atmosphere of Venus is highly toxic and inhospitable, but astronomers on Earth, with the help of powerful telescopes, have discovered plausible signs of life in the form of phosphine. Phosphine, a highly toxic gas, is a phosphorus atom with three hydrogen atoms attached. After much analysis, the scientists assert that something now alive is the only explanation for the chemical’s source.
This is important because, if it is phosphine, and if it is life, it means that we are not alone and that there must be many other inhabited planets throughout our galaxy.
Venus is wrapped in a thick, toxic atmosphere that traps in heat. Surface temperatures of Venus are like that of a blast furnace and reach a scorching 880 degrees Fahrenheit (471 degrees Celsius), hot enough to melt lead. Hot enough to melt metal and with clouds full of acid, any life that could survive in the atmosphere of Venus would have to be capable of enduring extremes.
Scientists have suspected that the Venusian high clouds, with mild temperatures around 86 degrees Fahrenheit (30 degrees Celsius), could harbour aerial microbes with extreme acidity-enduring properties. These clouds are around 90 per cent sulphuric acid. Earth microbes could not survive that acidity.
On Earth, microorganisms in ‘anaerobic’ environments produce phosphine. These include sewage plants, swamps, rice fields, marshlands, lake sediments, and the excrements and intestinal tracts of many animals. Phosphine also arises non-biologically in certain industrial settings. To produce phosphine, Earth bacteria take up phosphate from minerals or biological material and add hydrogen.
With scientists’ current knowledge of phosphine, and Venus, and geochemistry, they cannot explain the presence of phosphine in the clouds of Venus. That doesn’t mean it is life. It just means that some exotic process is producing phosphine.
Venus should be hostile to phosphine. Its surface and atmosphere are rich in oxygen compounds that would rapidly react with and destroy phosphine. However, something must be creating the phosphine on Venus as fast as it is being destroyed.
How the research started?
Jane Greaves, an astronomer at Cardiff University in Wales, had set out in June 2017 to test that hypothesis using the James Clerk Maxwell Telescope in Hawaii, looking for signs of various molecules on Venus. Different species of molecules absorb radio waves coming through the clouds at different characteristic wavelengths. One of the chemicals was phosphine, which she did not expect to find.
On rocky planets like Earth and Venus, there is not enough energy to produce copious amounts of phosphine. There is one thing, however, that appears to be very good at producing it: anaerobic life, or microbial organisms that don’t require or use oxygen. But scientists have yet to explain how Earth microbes make it.
The team needed a more powerful telescope, and the scientists next used the Atacama Large Millimeter Array, in Chile, in March 2019.
This time, they found all signs pointed to phosphine, ranging from 5 to 20 parts per billion. Such living things would have had to evolve to survive in a high-acid environment, perhaps with protective outer layers similar to microscopic organisms in Earth’s most extreme environments.
These microbes probably originated on the surface when Venus had oceans as late as 700 million years ago, but they were forced into the skies when the planet dried up.
And whether the microbes, if real, are based on a DNA like us, or something entirely different, is yet to be seen.
Courtesy: Reuters, Sept 16, 2020; The New York Times, Sept 14, 2020