The search for life beyond Earth has largely revolved around our rocky red neighbor. NASA has launched multiple rovers over the years to sift through Mars’ dusty surface for signs of water and other hints of habitability.
Now, in a surprising twist, scientists at MIT, Cardiff University, and elsewhere have observed what may be signs of life in the clouds of our other, even closer planetary neighbor, Venus. While they have not found direct evidence of living organisms there, if their observation is indeed associated with life, it must be some sort of “aerial” life-form in Venus’ clouds — the only habitable portion of what is otherwise a scorched and inhospitable world. Their discovery and analysis is published in the journal Nature Astronomy.
The astronomers detected in Venus’ atmosphere a spectral fingerprint, or light-based signature, of phosphine. MIT scientists have previously shown that if this stinky, poisonous gas were ever detected on a rocky, terrestrial planet, it could only be produced by a living organism there.
The MIT team followed up the new observation with an exhaustive analysis to see whether anything other than life could have produced phosphine in Venus’ harsh, sulfuric environment. Based on the many scenarios they considered, the team concludes that there is no explanation for the phosphine detected in Venus’ clouds, other than the presence of life.
Credits: Image: ESO (European Space Organization)
Venus is often referred to as Earth’s twin, as the neighboring planets are similar in their size, mass, and rocky composition. They also have significant atmospheres, although that is where their similarities end. Where Earth is a habitable world of temperate oceans and lakes, Venus’ surface is a boiling hot landscape, with temperatures reaching 900 degrees Fahrenheit and a stifling air that is drier than the driest places on Earth.
Much of the planet’s atmosphere is also quite inhospitable, suffused with thick clouds of sulfuric acid, and cloud droplets that are billions of times more acidic than the most acidic environment on Earth. The atmosphere also lacks nutrients that exist in abundance on a planet surface.
There is, however, a narrow, temperate band within Venus’ atmosphere, between 48 and 60 kilometers above the surface, where temperatures range from 30 to 200 degrees Fahrenheit. Scientists have speculated, with much controversy, that if life exists on Venus, this layer of the atmosphere, or cloud deck, is likely the only place where it would survive. And it just so happens that this cloud deck is where the team observed signals of phosphine.
News Source: MIT
