The search for extraterrestrial life has largely focused on Mars, but scientists at MIT, Cardiff University, and elsewhere reported surprising findings in September of what may be signs of life in the clouds of Venus.
While Venus is similar to Earth in size, mass, and rocky composition, its surface temperatures reach 900 °F, and its atmosphere is suffused with thick clouds of sulfuric acid billions of times more acidic than any environment on Earth.
There is, however, a narrow band 48 to 60 kilometers above the surface where temperatures range from 30 to 200 °F. In this temperate region the astronomers detected a pattern of light associated with phosphine, a stinky, poisonous gas that MIT astronomers have shown cannot be produced on rocky planets by any means other than living organisms. The team used computer models to explore all other mechanisms that might produce phosphine in Venus’s harsh environment and came up empty.
If there is indeed life on Venus, the researchers say, it is some “aerial” form that exists only in this band of clouds.
“A long time ago, Venus is thought to have had oceans, and was probably habitable like Earth,” says coauthor Clara Sousa-Silva, a former research scientist in the Department of Earth, Atmospheric, and Planetary Sciences. “As Venus became less hospitable, life would have had to adapt, and they could now be in this narrow envelope of the atmosphere where they can still survive.”