The quest for life beyond Earth revolves mostly around our rocky red neighborhood. NASA has launched several new rovers over the years to pass through the dusty surface of Mars for water signs and other signs of habitation, with a new route currently underway.
Now, in a surprising turn, scientists at MIT, Cardiff University and elsewhere have observed what signs of life might be in the clouds of neighboring Venus, one of our nearest planets. While they have not found direct evidence of living organisms there, if their observation is really related to life, it must be some kind of “aerial” life-form in the clouds of Venus – otherwise the only habitable part of the world. His findings and analysis are published in the journal Today Nature astronomy.
Astronomers led by Jane Greaves of Cardiff University discovered a spectral fingerprint or light-based signature of phosphine in the atmosphere of Venus.. MIT scientists have previously shown that if this foul-smelling, toxic gas was discovered on a rocky, terrestrial planet, it could only be produced by living organisms there. The researchers used the James Clark Maxwell Telescope (JCMT) in Hawaii and the Atacama Large Millimeter Array (ALMA) in Chile.
The MIT team followed the new observation by conducting a thorough inspection to see if Venus could produce anything other than life in the harsh, sulfuric atmosphere. Based on many of the scenarios they have considered, the team concludes that there is no explanation for the phosphine found in the clouds of Venus other than the presence of life.
“It’s very difficult to prove negative,” says Clara Sosa-Silva, a research scientist at MIT’s Department of Earth, Atmospheric and Eclipse Sciences (EAPS). “Now, astronomers will think of all the ways to justify phosphine without life, and I welcome that. Please, because we are at the end of our possibilities to show the amazing processes that phosphine can make. “
“This means that either this is life, or it is some kind of physical or chemical process that we do not expect to happen on reckless planets,” adds Janus Petkowski, co-author and EAPS research scientist.
Other MIT co-authors include William Bains, Sukrut Ranjan, Zuchang Zhan and Sara Caesar of the 1941 class of Planetary Science with appointments in the departments of Physics and Aeronautics and Astronautics at Cardiff University. College Ledge, Royal Observatory Greenwich, Open University and East Asian Observatory.
Discovery of foreign objects
Venus is often referred to as Earth’s twin, as neighboring planets are similar in size, mass, and rocky formation. They also have a significant atmosphere, although that’s where their similarities end. Where the Earth is a habitable world of temperate oceans and lakes, the surface of Venus is a boiling hot landscape, with temperatures reaching 900 degrees Fahrenheit and drier air than the dry places on Earth.
Much of the Earth’s atmosphere is also quite hospitable, plagued by thick clouds and cloud drops of sulfuric acid, which is billions of times more acidic than Earth’s most acidic atmosphere. The atmosphere also lacks nutrients that are abundant on the planet’s surface.
“Venus is a very challenging environment for any kind of life,” Caesar said.
However, inside the atmosphere of Venus there is a narrow, temperate strip, between 48 and 60 kilometers above the surface, where the temperature is 30 to 200 degrees Fahrenheit. Scientists have speculated with great controversy that if life lived on Venus, this layer of the atmosphere or the length of the cloud would probably be the only place where it would live. And it just so happens that this is the cloud deck where the team observed the signs of phosphine.
“This phosphine signal is in perfect place where others have speculated that the area is habitable,” says Petkowski.
The discovery was first made by Greaves and his team, who zeroed in on the use of JCMT on Venus’s atmosphere for a light sample that could indicate the presence of unexpected molecules and potential signatures of life. When he chose a pattern indicating the presence of phosphine, he approached Sosa-Silva, who has spent most of his career featuring odors, a toxic molecule.
Sosa-Silva initially assumed that astronomers could find phosphine as a biosignature on many future planets. “I was really thinking from afar, a lot of parsecs were far away, and really our nearest planet was not literally thinking.”
The team followed Greaves ’initial observation with the help of a more sensitive ALMA observatory with the help of Anita Richards of the University of Manchester’s Alma Regional Center. Those observations confirmed that what Greaves observed was actually a pattern of light that matched what phosphine gas would come out of the clouds of Venus.
The researchers then used a model of the Venetian atmosphere, developed by Hideo Sagawa of Kyoto Sangyo University, to interpret the data. They discovered that phosphin is a tiny gas on Venus that exists at a concentration of about 20 per billion atoms in the atmosphere. However, that concentration is low, the researchers said, adding that phosphine produced by life on Earth can also be found in the atmosphere at low concentrations.
The MIT team led by Bains and Petkowski used computer models to explore all the possible chemical and physical pathways associated with life that could produce phosphine in Venus’s harsh atmosphere. Bains was considering various scenarios that could produce phosphine, such as sunlight, surface minerals, volcanic activity, meteor strikes, and lightning. Ranjan and Paul Reimer of Cambridge University, then modeling how phosphine, produced by these mechanisms, can accumulate in the clouds of Venus. In each of the scenarios they have considered, the phosphine that is produced is only a small fraction of what the new observation on the clouds of Venus suggests.
“We actually went through all the possible routes that could produce phosphine on a rocky planet,” says Petkowski. “If this is not life, then our understanding of rocky planets is severely lacking.”
A life of clouds
If Venus clouds have real life, the researchers believe it is an aerial form, just above the surface of the volcano, boiling in Venus’s temperate cloud deck.
Sosa-Silva says, “Long ago Venus was thought to have oceans, and it was probably like Earth. Was worth living. “With Venus becoming less hospitable, life would have had to be adapted, and now they could be in this narrow envelope of the atmosphere where they could still live. This could show that even a planet on the edge of a habitable zone may have an atmosphere with a local aerial habitable envelope.
In a separate line of research, Searle and Petkowski explored the possibility that the lower layers of Venus’s atmosphere, below the cloud deck, could be crucial to the existence of an imaginary Venetian biosphere.
“In theory, you could keep the life cycle in the clouds forever,” says Petkowski, “basically any aerial Venus imagines life more than life on Earth. “The liquid medium on Venus is not water, as it is on Earth.”
Sosa-Silva is now leading efforts with Jason Dittman at MIT to confirm the discovery of phosphine with other telescopes. They hope to map the presence of molecules in the entire atmosphere of Venus, to see if there are daily or seasonal variations in the signal that indicate the activity associated with life.
Sosa-Silva says that, technically, biomolecules were previously found in the atmosphere of Venus, but these molecules are also associated with a thousand things other than life. “Phosphine is a special cause, it is very difficult to make phosphine on rocky planets without life. Earth has been the only terrestrial planet where we have found phosphine, because there is life here. till now.”
The research was funded by Horizon, in part, funded by the Council on Science and Technology, the European Southern Observatory, the Japan Society for the Promotion Science, the Hising-Simmons Foundation, the Change Happens Foundation, the Simmons Foundation and the European Union. 2020 Research and Innovation Program.
.
