For years, humans have searched for life beyond Earth mainly around mars, the red planet. NASA has launched multiple Mars rovers in search of signs of water and other habitability.
But now, surprisingly, scientists at multiple universities such as the Massachusetts Institute of Technology (MIT), Cardiff University, and others have observed that our other, closer planetary neighbor, may have signs of life in the clouds of Venus!
Although the researchers have yet to find direct evidence of the existence of living things there, if their findings are indeed related to life, it must be some kind of "in the air" life form living in The atmosphere of Venus. Their findings and analysis were published in the journal Nature Astronomy.
< h1 class="pgc-h-arrow-right" > phosphine was discovered</h1>
The research began with the discovery of phosphine. A team of researchers led by Jane Grifs of Cardiff University detected spectroscopic or optical signatures of phosphine in Venus's atmosphere. Scientists at MIT have previously shown that if this toxic gas is found on a rocky planet, it can only be produced by living organisms there.
Jane Grifves
The MIT team conducted a detailed analysis of the Greaves group's observations to see if there is another cause for phosphine production in Venus' harsh sulfuric acid environment than life. But ultimately, they concluded that there was no reason to produce phosphine in Venus' atmosphere other than the existence of life.
Clara Susa-Silva, a research scientist in MIT's Department of Earth, Atmosphere, and Planetary Sciences (EAPS), said: "It is very difficult to prove a negative conclusion. "Now, astronomers will come up with all the ways to justify the existence of abiotically produced phosphine, and I welcome that." Please do it, because we are nearing the end of the possibility of demonstrating the abiotic processes that produce phosphine. ”
Clara Susa-Silva
"That means that's life, or it's some sort of physical or chemical process that we don't expect to happen on a rocky planet," added co-author Janus Petkovsky, an EAPS research scientist.
In addition to MIT and Cardiff University, the study brought together scientists from the University of Manchester, the University of Cambridge, the MRC Molecular Biology Laboratory, Kyoto Institute of Technology, Imperial University, the Royal Observatory Greenwich, the Open University and the East Asian Observatory.
<h1 class="pgc-h-arrow-right" > ignored Venus</h1>
Venus is often referred to as Earth's twin because it is similar to Earth in size, mass, and rock composition. Venus also has a thick atmosphere, but it is completely different from Earth's atmosphere. Earth is a habitable world with temperate oceans and lakes, while Venus's surface is a boiling landscape of high temperatures of up to 480 degrees Celsius, with suffocating air drier than the driest places on Earth.
Much of the planet's atmosphere is also rather uninhabitable, filled with thick clouds of sulfuric acid and droplets billions of times more acidic than the most acidic environment on Earth. The atmosphere also lacks nutrients rich in the planet's surface.
"Venus is a very challenging environment for any life," said Sarah Siegel, a MIT professor and paper collaborator.
Sarah Siegel
However, there is a narrow temperate zone in Venus' atmosphere, located 48 to 60 kilometers from the surface of Venus, with temperatures ranging from minus 1 degree Celsius to 93 degrees Celsius. Scientists speculate that if there is life on Venus, then this layer of the atmosphere is likely to be the only place where it can survive. Coincidentally, this section is where the team observed the phosphine signal.
Petkovsky said: "This phosphine signal is perfectly placed in a place that others think may be suitable for habitation. ”
<h1 class="pgc-h-arrow-right" > the result of teamwork</h1>
The presence of hydrogen sulfide was first accomplished by Greaves and her team, who used the James Clark Maxwell Telescope (JCMT) at the Monakya Observatory in Hawaii, USA, to observe The atmosphere of Venus and found anomalous spectra. This could indicate the presence of unexpected molecules and possible life features in Venus' atmosphere. When Greaves discovered it was phosphine, she contacted Susa Silva, a scientist who has spent much of his career describing the foul-smelling toxic molecule.
Susa-Silva originally thought astronomers could look for phosphine as a biological signal on planets farther away from Earth. "I was thinking about very far distances, a few parsec distances, not the closest planet to us."
With the help of Anita Richards at the University of Manchester's Alma Regional Centre, the team used the more sensitive Alma Observatory to continue tracking Greaves' initial observations. These observations confirm that what Greaves observed was indeed a spectrum that matched the phosphine gas released in the Venus Cloud.
The researchers then used a model of the Atmosphere of Venus developed by Hideo Sagawa of Kyoto Sangyo University to interpret the data. They found that phosphine on Venus is a rare gas, with only 20 phosphine molecules per 1 billion molecules in the atmosphere. Although this concentration is low, the researchers note that life on Earth produces even lower levels of phosphine in the atmosphere.
The MIT team, led by Baynes and Petkowski, used computer models to explore all possible chemical and physical pathways for producing phosphine. These pathways, which are not related to life, can produce phosphine in the harsh environment of Venus. Baines considered a variety of conditions that could produce phosphine, such as sunlight, surface minerals, volcanic activity, meteor impacts, and lightning.
Then, MIT postdoc Sukri Ranjan and Paul Rimer of the University of Cambridge built models of how phosphine produced through these mechanisms accumulates in the Venus cloud. In each of the cases they considered, the phosphine produced was only a fraction of the phosphine present in the new observations in the clouds of Venus.
Petkowski said: "We did consider all the pathways that could produce phosphine on rocky planets. "If that's not life, then our knowledge of rocky planets is woefully lacking."
< h1 class="pgc-h-arrow-right" > living in the cloud</h1>
If life does exist in Venus' clouds, the researchers believe it is a form of life in the air, existing only in Venus' temperate clouds, much higher than the surface of a boiling volcano.
"A long time ago, Venus was thought to have oceans and could be as habitable as Earth," Susa-Silva said. "When Venus became less habitable, life had to adapt, and they might now survive in this narrow atmosphere." This could suggest that even planets at the edge of the habitable zone may have habitable atmospheres. ”
In another study, Siegel and Petkowski explored the possibility that the lower layers of Venus's atmosphere, just below the clouds, might be critical to the survival of the hypothetical Venus biosphere.
"In principle, you can have a life cycle that keeps life in the clouds forever," said Petkowski, who believes that any Venusian life in the sky is fundamentally different from life on Earth. "The liquid medium on Venus is not water like on Earth."
Susa-Silva is now leading a study with Jason Dietman of MIT to further confirm phosphine detected with other telescopes. They also hope to map the distribution of such molecules in Venus' atmosphere to see if their signals change daily or seasonally, suggesting life activity.
"Technically, biomolecules have been found in Venus' atmosphere before, but these molecules are related to a thousand other things in addition to life," Susa-Silva said. ”
"Phosphine is special because it's hard to make phosphine on rocky planets without life. Earth is the only terrestrial planet where we've discovered phosphine because there's life here. Until now. ”