Life on Venus? Astronomers have detected the first sign of life in the deadly clouds of Venus. They found phosphine which displays a strong signature of life. If we can detect life itself soon, this might be the most exciting news in history.
Life on Venus’ clouds?
There has been speculation on the possibility that life exists in the upper cloud layers of Venus for a long time, at least since 1967 (see notes 1), 50 kilometers (30 miles) up from the surface, where the temperature ranges between 303 and 353 K (30 and 80 °C; 86 and 176 °F) but the environment is acidic.
Phosphine is actually a nasty gas, a toxic and explosive molecule with a lingering odor of garlic and dead fish. But, the detection of phosphine in Venus’ atmosphere, with no known pathway for abiotic production (which means there’s no known way it can be produced without life), led to speculation that there may be life currently present in the atmosphere.
So, finding even a small amount of phosphine on Venus is exciting, because of how the gas is made here on Earth: it’s either manufactured artificially by humans, into products like fumigants or biological weapons, or it’s a natural byproduct of life.
In trying to explain the existence of phosphine, Cardiff University astronomer Jane Greaves and her team used the Vega data (see notes 2) and modeled nearly 100 different chemical reactions in the atmosphere to see whether they could replicate the phosphine they’d detected.
Despite doing so over a number of conditions (pressure, temperature, the concentration of reactants), they found that none was viable. They also considered reactions below the surface, but in order to generate enough phosphine in this way, Venus would need to have volcanic activity at least two hundred times greater than that of Earth – which is not the case.
Can’t a meteorite carry phosphine to Venus? Scientists also considered this but found it would not result in the quantities of the material suggested by the results. Moreover, there is no evidence of a recent, large impact that may have raised concentrations of phosphorus in the atmosphere.
The team also investigated whether reactions with lightning or the solar wind could generate phosphine in the atmosphere but concluded that this would produce only small amounts.
If there’s life (even microbial) in the upper atmosphere of Venus, then we are most probably going to find life on many other planets and moons around other stars, and on some solar system bodies like Enceladus or Europa.
We found the signature of life on Venus, not the life itself – yet
While the new discovery is super exciting, it’s really important to not go around shouting “We found life on Venus”. It’s difficult to explain how you get phosphine without a biological source – but this is NOT the same as saying “phosphine 100% indicates life”.
Planetary Astrobiologist and Director of the Planetary Habitability Laboratory (a research and educational virtual lab studying the habitable universe from UPR Arecibo), Prof. Abel Méndez wrote on Twitter that:
“I think that the cloud environments of Venus are too dynamic and diluted to support a stable ecosystem. Thus, I believe that phosphine on Venus is chemically produced. Nevertheless, we have a new mystery that will need further modeling and observations to be solved.”
It never aliens, until it is.
- Study: Life in the Clouds of Venus? Harold Morowitz & Carl Sagan, published in Nature on 16 September 1967
- Vega 1 and Vega 2 were uncrewed spacecraft launched in a cooperative effort among the Soviet Union (who also provided the spacecraft and launch vehicle) and Austria, Bulgaria, France, Hungary, the German Democratic Republic, Poland, Czechoslovakia, and the Federal Republic of Germany in December 1984. They had a two-part mission to investigate Venus and also flyby Halley’s Comet.