If men are from Mars, there may be more life on Venus, was the thought perambulating scientific minds this week, upon the discovery of a strange gas in the atmosphere of our sister planet. A group of scientists led by Professor Jane Greaves from Cardiff University, using radio telescopes in Hawaii and Chile, have published a paper in the journal Nature Astronomy detailing their observations of phosphine in the Venusian clouds.
Made up of one phosphorous atom and three hydrogen atoms, the gas is a component of the Earth’s atmosphere at very low concentrations, and can be found in the gut bacteria of penguins or in oxygen-deprived wetlands and swamps. Traces exist in the atmospheres of the gas giants Jupiter and Saturn, formed in their hot interiors before breaking down in their upper atmospheres. On terrestrial Venus however, which boasts the hottest surface temperature of all the planets in our Solar System but lacks the same fiery interior, the scientists detected phosphine at a concentration which cannot be explained by known chemical processes, raising the possibility of some form of life.
At a distance of 50 kilometres from the planet’s surface, temperatures have cooled considerably. But the existence of life even this far up is complicated by the thick clouds of sulphuric acid which shroud Venus, in an arid climate with nowhere to land. In another paper published last month in the journal Astrobiology, the scientists posited microbes sealed inside droplets of sulphuric acid and water, but the description remains tenuous. Discussing the phosphine in the clouds of Venus, they write, ‘Even if confirmed, we emphasize that the detection of PH3 is not robust evidence for life, only for anomalous and unexplained chemistry’.
Such observations are likely to prompt further study. Between 1961 and 1984, the Soviet Venera programme produced a series of firsts, including the first successful landing of a spacecraft on another planet, and the first images from the planet’s surface. The Mariner programme by NASA conducted a series of flybys of Venus, while the Pioneer and Magellan spacecrafts entered orbit for a closer look.
The Venus Express, the first foray from the European Space Agency, sent back data between 2006 and 2014, while the Akatsuki probe from Japan continues to study the planet’s atmosphere. The European EnVision, Russian Venera-D, and Indian Shukrayaan-1 orbital and landing missions remain in the early planning stages, while two Venus missions could receive NASA funding in the next round of the Discovery programme.
