Biosphere of venus, coming to a planet near you?

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Biosphere of venus, coming to a planet near you?

Postby Harvey » Tue Sep 15, 2020 7:26 pm

Hints of life on Venus: Scientists detect phosphine molecules in high cloud decks

by Royal Astronomical Society

An international team of astronomers, led by Professor Jane Greaves of Cardiff University, today announced the discovery of a rare molecule—phosphine—in the clouds of Venus. On Earth, this gas is only made industrially, or by microbes that thrive in oxygen-free environments.

Astronomers have speculated for decades that high clouds on Venus could offer a home for microbes—floating free of the scorching surface, but still needing to tolerate very high acidity. The detection of phosphine molecules, which consist of hydrogen and phosphorus, could point to this extra-terrestrial 'aerial' life. The new discovery is described in a paper in Nature Astronomy.

The team first used the James Clerk Maxwell Telescope (JCMT) in Hawaii to detect the phosphine, and were then awarded time to follow up their discovery with 45 telescopes of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Both facilities observed Venus at a wavelength of about 1 millimeter, much longer than the human eye can see—only telescopes at high altitude can detect this wavelength effectively.

Professor Greaves says, "This was an experiment made out of pure curiosity, really—taking advantage of JCMT's powerful technology, and thinking about future instruments. I thought we'd just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus' spectrum, it was a shock!"

Naturally cautious about the initial findings, Greaves and her team were delighted to get three hours of time with the more sensitive ALMA observatory. Bad weather added a frustrating delay, but after six months of data processing, the discovery was confirmed.

Team member Dr. Anita Richards, of the UK ALMA Regional Centre and the University of Manchester, adds: "To our great relief, the conditions were good at ALMA for follow-up observations while Venus was at a suitable angle to Earth. Processing the data was tricky, though, as ALMA isn't usually looking for very subtle effects in very bright objects like Venus."

Greaves adds: "In the end, we found that both observatories had seen the same thing—faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below."

Professor Hideo Sagawa of Kyoto Sangyo University then used his models for the Venusian atmosphere to interpret the data, finding that phosphine is present but scarce—only about twenty molecules in every billion.

The astronomers then ran calculations to see if the phosphine could come from natural processes on Venus. They caution that some information is lacking—in fact, the only other study of phosphorus on Venus came from one lander experiment, carried by the Soviet Vega 2 mission in 1985.

Massachusetts Institute of Technology scientist Dr. William Bains led the work on assessing natural ways to make phosphine. Some ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough of it. Natural sources were found to make at most one ten thousandth of the amount of phosphine that the telescopes saw.

To create the observed quantity of phosphine on Venus, terrestrial organisms would only need to work at about 10% of their maximum productivity, according to calculations by Dr. Paul Rimmer of Cambridge University. Any microbes on Venus will likely be very different to their Earth cousins though, to survive in hyper-acidic conditions.

Earth bacteria can absorb phosphate minerals, add hydrogen, and ultimately expel phosphine gas. It costs them energy to do this, so why they do it is not clear. The phosphine could be just a waste product, but other scientists have suggested purposes like warding off rival bacteria.

Another MIT team-member, Dr. Clara Sousa Silva, was also thinking about searching for phosphine as a 'biosignature' gas of non-oxygen-using life on planets around other stars, because normal chemistry makes so little of it.

She comments: "Finding phosphine on Venus was an unexpected bonus! The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment—but the clouds of Venus are almost entirely made of acid."

Other possible biosignatures in the Solar System may exist, like methane on Mars and water venting from the icy moons Europa and Enceladus. On Venus, it has been suggested that dark streaks where ultraviolet light is absorbed could come from colonies of microbes. The Akatsuki spacecraft, launched by the Japanese space agency JAXA, is currently mapping these dark streaks to understand more about this 'unknown ultraviolet absorber.'

The team believes their discovery is significant because they can rule out many alternative ways to make phosphine, but they acknowledge that confirming the presence of "life" needs a lot more work. Although the high clouds of Venus have temperatures up to a pleasant 30 degrees centigrade, they are incredibly acidic—around 90% sulphuric acid—posing major issues for microbes to survive there. Professor Sara Seager and Dr. Janusz Petkowski, also both at MIT, are investigating how microbes could shield themselves inside droplets.

The team are now eagerly awaiting more telescope time, for example to establish whether the phosphine is in a relatively temperate part of the clouds, and to look for other gases associated with life. New space missions could also travel to our neighboring planet, and sample the clouds in situ to further search for signs of life.

Professor Emma Bunce, President of the Royal Astronomical Society, congratulated the team on their work, "A key question in science is whether life exists beyond Earth, and the discovery by Professor Jane Greaves and her team is a key step forward in that quest. I'm particularly delighted to see UK scientists leading such an important breakthrough—something that makes a strong case for a return space mission to Venus."

Science Minister Amanda Solloway said, "Venus has for decades captured the imagination of scientists and astronomers across the world."

"This discovery is immensely exciting, helping us increase our understanding of the universe and even whether there could be life on Venus. I am incredibly proud that this fascinating detection was led by some of the UK's leading scientists and engineers using state of the art facilities built on our own soil."

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Re: Biosphere of venus, coming to a planet near you?

Postby BenDhyan » Thu Oct 15, 2020 5:16 pm

Astronomers Report They’ve Detected the Amino Acid Glycine in the Atmosphere of Venus

Posted on October 15, 2020 by Evan Gough

Does it feel like all eyes are on Venus these days? The discovery of the potential biomarker phosphine in the planet’s upper atmosphere last month garnered a lot of attention, as it should. There’s still some uncertainty around what the phosphine discovery means, though.

Now a team of researchers claims they’ve discovered the amino acid glycine in Venus’ atmosphere.

The paper announcing the finding is titled “Detection of simplest amino acid glycine in the atmosphere of the Venus.” The lead author is Arijit Manna, a Ph.D. Research Scholar in the Dept. of Physics at Midnapore College in West Bengal, India. The paper is at the pre-print site, which means it hasn’t been peer-reviewed and published in a journal… yet.

There are about 500 known amino acids, but only 20 are present in the genetic code. Glycine is the simplest of them.
Though glycine and other amino acids aren’t biosignatures, they are some of the building blocks of life. In fact, they’re the building blocks of proteins. They were also some of the first organic molecules to appear on Earth. Glycine is important for the development of proteins and other biological compounds.

The researchers used the Atacama Large Millimeter/submillimeter Array (ALMA) to detect glycine in Venus’ atmosphere with spectroscopy. They found it in the mid-latitudes, near the equator. That’s where the signal was strongest, and there was none detected at the poles.

In their paper, the authors write “Its detection in the atmosphere of Venus might be one of the keys to understanding the formation mechanisms of prebiotic molecules in the atmosphere of Venus. The upper atmosphere of Venus may be going through nearly the same biological method as Earth billions of years ago.”

Those two sentences pack a real punch. Could there be some kind of biological process going on in the clouds of Venus? It “might” be one of the keys, and it “may be going” through the same thing Earth did. What does it mean?
First Phosphine, Then Glycine

In mid-September, a team of researchers reported finding phosphine in the upper atmosphere of Venus (Greaves et al, 2020). Like glycine, it was also detected more strongly at mid-latitudes. Phosphine can be a biosignature and is on Earth. But it can also be created chemically, though that requires an enormous amount of energy. It’s been detected at Jupiter and Saturn, where there’s abundant energy for its production. But Venus doesn’t have the required energy to create it.

That team of researchers that discovered phosphine was circumspect with regards to their own findings. In their paper, they almost pleaded with other researchers to account for phosphine’s presence without invoking life. “Now, astronomers will think of all the ways to justify phosphine without life, and I welcome that. Please do, because we are at the end of our possibilities to show abiotic processes that can make phosphine.”

Then a couple of weeks later, another team of researchers did just that. In their paper, called a hypothesis perspective, they said that volcanoes could account for the phosphine. “We hypothesize that trace amounts of phosphides formed in the mantle would be brought to the surface by volcanism, and then subsequently ejected into the atmosphere, where they could react with water or sulfuric acid to form phosphine.”

The detection of phosphine forms the background for this latest discovery. Both discoveries are part of the larger questions around Venus: Is their life or the potential for life at Venus? Or are these chemicals unrelated to life?

Researchers have identified a region of Venus’ atmosphere that might be able to host life. It would be a bizarre and unusual arrangement from our perspective.

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Re: Biosphere of venus, coming to a planet near you?

Postby DrEvil » Sat Oct 17, 2020 4:25 pm

Did NASA detect a hint of life on Venus in 1978 and not realize it?

By Rafi Letzter 11 days ago

What if scientists had started hunting for life on Venus in 1978?

If life does exist on Venus, NASA may have first detected it back in 1978. But the finding went unnoticed for 42 years.

Life on Venus is still a long shot. But there's reason to take the idea seriously. On Sept. 14, a team of scientists made a bombshell announcement in the journal Nature Astronomy: Using telescopes, they'd detected phosphine, a toxic gas long proposed as a possible sign of alien microbial life, in the upper part of the planet's thick atmosphere. The detection was a landmark in the long hunt for life elsewhere in the solar system, which has mostly focused attention on Mars and a few moons orbiting Jupiter and Saturn. Meanwhile, Venus, hot and poisonous, was long considered too inhospitable for anything to survive. But now, digging through archival NASA data, Rakesh Mogul, a biochemist at Cal Poly Pomona in California, and colleagues have found a hint of phosphine picked up by Pioneer 13 — a probe that reached Venus in December 1978.

"When the [Nature Astronomy paper] came out, I immediately thought of the legacy mass spectra," Mogul told Live Science.

Mogul and his coauthors were broadly familiar with the data from the missions, he said. "So, for us, it was a natural next step to give the data another look. As such, after consulting with my co-authors, we identified the original scientific articles, and promptly started looking for phosphorous compounds."

The discovery, published to the arXiv database Sept. 22 and not yet peer reviewed, doesn't tell researchers much beyond what was reported in Nature Astronomy — though it does make the presence of phosphine (made up of a phosphorus atom and three hydrogens) even more certain, they said. The 1978 data comes from the Large Probe Neutral Mass Spectrometer (LNMS), one of several instruments that descended into Venus' atmosphere as part of the Pioneer 13 mission.

Pioneer 13 dropped a large probe (the LNMS) into Venus' clouds; suspended from a parachute, the probe collected data and beamed it back to Earth as it plummeted toward its robotic death. (Three smaller probes also dropped from Pioneer 13 without parachutes.) The LNMS sampled the atmosphere and ran those samples through mass spectrometry, a standard lab technique used to identify unknown chemicals. When scientists first described the LNMS results in the 1970s, they didn't discuss phosphorus-based compounds like phosphine, focusing instead on other chemicals.

When Mogul's team reexamined the LNMS data from Venus' lower and middle clouds (a potential habitable zone on the planet), they found signals that look a great deal like phosphine, the researchers wrote. The scientists also found definitive evidence for atoms of phosphorus in the atmosphere, which likely came from a heavier gas such as phosphine.

LNMS wasn't built to hunt phosphine-like compounds, and would have had a hard time distinguishing the gas from other molecules that have similar masses. But Pioneer 13's sample did have evidence of some molecule present in the gas that had the same mass as phosphine — in amounts that match the levels described in the Nature Astronomy paper.

"I believe that evidence for [trace chemicals that could be signatures of life] in the legacy data were sort of discounted because it was thought that they could not exist in the atmosphere," Mogul said. "I think many people are now revisiting the notion of Venus as a fully oxidizing environment." (A "fully oxidizing environment" wouldn't include phosphine or most other chemicals seen as signs of life.)

Mogul and his colleagues also found hints of other chemicals that shouldn't arise naturally in Venus' clouds — substances like chlorine, oxygen and hydrogen peroxide.

"We believe this to be an indication of chemistries not yet discovered," they wrote, "and/or chemistries potentially favorable for life."

What's needed, they wrote, is further, sustained exploration of Venus.

"We need a more sustained approach for exploration like that of Mars," Mogul said.

NASA and the European, Indian and Russian space agencies have plans for Venus probes that might be helpful, he said.

"However, when considering the past, current, and future habitability of Venus, we would need longer-term chemical and geology studies to understand the sources of any potential chemical [anomalies] in the clouds," he said. "This could be from orbital probes, balloon-suspended probes in the clouds, and/or heat-stable lander probes."

The phrase "heat-stable" is important, given the planet's habit of killing any robot that lands on its sizzling hot surface.

Originally published on Live Science.
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