Scientists said on Monday (September 14) they have detected in the harshly acidic clouds of Venus a gas called phosphine that indicates microbes may inhabit Earth’s inhospitable neighbour, a tantalising sign of potential life beyond Earth.
The researchers did not discover actual life forms, but noted that on Earth phosphine is produced by bacteria thriving in oxygen-starved environments. The international scientific team first spotted the phosphine using the James Clerk Maxwell Telescope in Hawaii and confirmed it using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in Chile. The research continues to either confirm the presence of life or find an alternative explanation.
The existence of extraterrestrial life long has been one of the paramount questions of science. Scientists have used probes and telescopes to seek “biosignatures” – indirect signs of life – on other planets and moons in our solar system and beyond.
Some scientists have suspected that the Venusian high clouds, with mild temperatures around 86 degrees Fahrenheit (30 degrees Celsius), could harbour aerial microbes that could endure extreme acidity. These clouds are around 90% sulphuric acid. Earth microbes could not survive that acidity.
On Earth, microorganisms in “anaerobic” environments – ecosystems that do not rely on oxygen – 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.
Venus is Earth’s closest planetary neighbour. Similar in structure but slightly smaller than Earth, it is the second planet from the sun. Earth is the third. Venus is wrapped in a thick, toxic atmosphere that traps in heat. Surface temperatures reach a scorching 880 degrees Fahrenheit (471 degrees Celsius), hot enough to melt lead.