Recent news has highlighted the discovery of phosphine in the atmosphere of Venus by scientists. This finding forges a potential path towards the existence of life forms on Venus.
The international scientific team employed the James Clerk Maxwell Telescope (JCMT) in Hawaii for initial phosphine spotting and then confirmed their findings using the Atacama Large Millimeter/submillimeter Array (ALMA)—the largest radio telescope in the world—located in Chile.
While no actual life forms were found, it is essential to note that on Earth, phosphine is a product of bacteria flourishing in environments lacking oxygen.
Biosignatures and the Search for Life Beyond Earth
Scientists have long exploited both probes and telescopes in their quest for “biosignatures”—indirect indications of life—on other celestial bodies within our solar system and beyond.
Venus’s atmosphere was found to contain phosphine at a trace concentration of 20 parts-per-billion. Despite this, Venus itself is viewed as hostile towards phosphine, with an atmosphere and surface rich in oxygen compounds known to react rapidly with and eliminate phosphine.
Phosphine is recognized as a biosignature due to its primary production via biological processes, rather than any naturally occurring chemical processes. Interestingly, the European Space Agency’s Venus Express mission discovered signs of ozone, another biomarker, in Venus’s upper atmosphere back in 2011.
The Acid Test: Could Life Exist in the High Clouds of Venus
Scientists have hypothesized that Venus’s high clouds, boasting mild temperatures around 86 degrees Fahrenheit, could shelter aerial microbes able to endure extreme acidity — these clouds are approximately 90% sulphuric acid, a condition unsuitable for Earth microbes.
Furthermore, on rocky planets like Venus and Earth, phosphine can only be created by life—whether human or microbe. On Earth, some species of anaerobic bacteria—which thrive in oxygen-starved environments such as landfills, marshlands, and animal guts—naturally produce phosphine.
What is Phosphine?
Phosphine (PH3) consists of one phosphorus atom bonded to three hydrogen atoms. It is highly toxic to humans. Aside from being a byproduct of certain types of bacteria, phosphine can also be generated non-biologically in industrial settings and was even utilized as a chemical weapon during World War I.
Venus: Earth’s Menacing Twin
Venus, often referred to as Earth’s twin due to its similar structure and close proximity, is the second planet from the sun. Early observations revealed that Venus possesses a lethal set of conditions capable of snuffing out life. The planet is enveloped in a dense and toxic atmosphere that locks in heat, with surface temperatures reaching a sweltering 880 degrees Fahrenheit.
The Way Forward: Exploring Venus
This intriguing finding could reignite interest in launching space missions to Venus. There is already a history of spacecraft venturing close to the planet since the 1960s, with some even managing to land. All forthcoming missions will now prioritize the search for further evidence of life.
The Indian Space Research Organisation (ISRO) is already planning a mission to Venus, tentatively titled Shukrayaan. While exploration endeavors face challenges such as Venus’s high surface temperature, dense atmosphere, and corrosive sulphuric acid presence, there is significant potential for groundbreaking discoveries in our ongoing quest to detect extraterrestrial life.
