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Astronomers find possible signs of life on Venus



Traces of a rare molecule known as phosphine have been found in Venus’s hellish and highly acidic atmosphere, astronomers announced Monday, providing a tantalizing clue to the possibility of life. The phosphine molecules found on Earth are primarily the result of human industry or the actions of microbes that thrive in oxygen-free environments.

The researchers do not claim that life was detected on the second planet by the sun. But the observations at least suggest the possibility of microbial activity in the upper layers of Venus’s atmosphere, well away from the planet’s inhospitable surface.

“We have detected a rare gas called phosphine in the atmosphere of our neighboring planet Venus,”

; said Jane Greaves, a professor at Cardiff University in the UK and lead author of a report published in Nature Astronomy. “And the reason for our excitement is that the phosphine gas on Earth is produced by microorganisms that live in oxygen-free environments. And so there is a possibility that we have detected some sort of living organism in the clouds of Venus.”

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A false color image of Venus captured by the Ultraviolet Imager aboard Japan’s Venus Climate Orbiter (Akatsuiki).

JAXA


Even so, the team said, far more studies are needed to support any such claim, however extraordinary it may be.

“To make this rather extraordinary claim that there may be life there, we really have to rule out everything, which is why we are very cautious saying that we are not stating that there is life, but that there is something that is truly unknown and could be. life, “said team member William Bains, an MIT researcher.

Sara Seager, an MIT scientist who studies the atmospheres of exoplanets, agrees, saying “we are not claiming to have found life on Venus.”

“We are vindicating the confident detection of phosphine gas whose existence is a mystery,” he said. “Phosphine may be produced by some (non-biological) processes on Venus, but only in such incredibly small quantities is not enough to explain our observation. So we are left with this other exciting and tantalizing possibility: that perhaps there is some kind of life in the clouds of Venus “.

Mars has long been considered the best candidate in the solar system beyond Earth for hosting microbial life in the distant past or even in the present, as suggested by background levels of methane. NASA, the European Space Agency, China, India, Russia and the United Arab Emirates are all chasing exploration of the red planet in one form or another.

NASA is also planning a flagship mission to study the moons of Jupiter. Scientists believe that one of the largest and most known moons on the planet, Europe, heated by tidal tensions and gravitational interactions with other moons, it hosts a salty, possibly habitable ocean beneath its icy crust. Other frozen moons in the outer solar system, possible “water worlds”, are also candidates for study.

But Venus is the victim of a runaway greenhouse effect in which thick clouds in a predominantly carbon dioxide atmosphere trap sunlight, producing surface temperatures that rise to nearly 900 degrees, hot enough to melt lead.

In the planet’s upper atmosphere, however, temperatures are much more hospitable. Despite the acidic nature of the clouds, scientists have speculated that alien microbes might be possible.

“The surface conditions today are really hostile, the temperature is enough to melt our landers,” Greaves said. “But it is thought that much earlier in the history of Venus the surface was much colder and wetter and life may have originated.

“There is a longstanding theory that some of the smaller life forms may have been able to evolve upward in high clouds. The conditions are certainly not beautiful, they are extremely acidic and there is a lot of wind. but on the other hand, if you talk from 50 to 60 kilometers high, the pressure is very similar to that on the surface of the Earth and the temperature is quite good, maybe up to about 85 degrees Fahrenheit. So it has been assumed that this is a living habitat today. “

Greaves’ team studied the spectra of Venus’s atmosphere using the James Clerk Maxwell Telescope in Hawaii and 45 radio telescope antennas in the Atacama Large Millimeter / submillimeter Array in Chile and were surprised to see unmistakable signs of phosphine. “It was a shock,” Greaves said.

The detection was rewarded with additional observation time on the ALMA array and “in the end, we found that both observers had seen the same thing, a weak absorption at the right wavelength from phosphine gas, where the molecules are backlit. from the warmer clouds below, “Greaves said in a statement.

Only traces were observed, about 20 molecules per billion. But further research showed that natural sources of phosphine – volcanoes, lightning, minerals exploded in the atmosphere, the action of sunlight – would generate only one ten-thousandth of the amount actually detected.

The team can rule out many non-biological ways to generate observed phosphine levels, but that doesn’t mean life is the only explanation. Venus’ atmosphere is 90 percent sulfuric acid, which raises “many questions, such as how organisms might survive,” said MIT researcher Cara Sousa Silva.

“On Earth, some microbes can tolerate up to about 5 percent acid in their environment, but the clouds of Venus are almost entirely made of acid,” he said.

Greaves’ team is waiting more time for the telescope to look for signs of other gases associated with biological activity and to determine the cloud temperature where phosphine is present to get more information. Ultimately, future spacecraft visits will likely be needed to fully resolve the issue.

“There can always be something that we overlooked,” Seager said. “Ultimately, the only thing that will answer this question for us – there is life, there is no life – is actually going to Venus and making more detailed measurements for the signs of life and perhaps life itself.”




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