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Signs of life on Venus?

All around the world are dawning headlines wondering if we have founds signs of life on Venus.

Despite the hunt for life on star systems that are lightyears from Earth, it turns out there may be something on the Planet-next-door. “May” being the operative word. A team found phosphine in the atmosphere of Venus and can’t think of any other way it could have got there. Phosphine is considered to be a biomarker. And microbes on Earth would have no trouble making it, though none of them could easily survive on Venus where the atmosphere clouds and rain are nearly pure hot sulphuric acid.*

Scientists find gas linked to life in atmosphere of Venus

Ian Sample, The Guardian

Sara Seager, a planetary scientist on the study at MIT in the US, called the finding “mind-boggling”. She hypothesises a lifecycle for Venusian microbes that rain down, dry out and are swept back up to more temperate altitudes by currents in the atmosphere.

For 2bn years, Venus was temperate and harboured an ocean. But today, a dense carbon dioxide atmosphere blankets a near-waterless surface where temperatures top 450C. The clouds in the sky are hardly inviting, containing droplets of 90% sulphuric acid.

“It’s completely startling to say life could survive surrounded by so much sulphuric acid,” said Prof Jane Greaves, an astronomer at Cardiff University, leader of the team who made the discovery. “But all the geological and photochemical routes we can think of are far too

There are still a lot of ducks that need to line up before we could say we’ve found life on Venus (if it exists). It’s a competition  of disbelief — we can’t believe lightning or volcanoes could have made that much phosphine and we can’t believe microbes can live in near pure sulphuric acid either.

Still, it’s interesting to wonder  whether life could have evolved on Venus during that two billions years of oceans and this is all that’s left? If there were once fish on Venus, how would we know on a 450 degree C planet, and from 200 million years in the future and from Earth?

Scientists Find a Possible Sign of Life on Venus

by Maria Korean, The Atlantic

Venus is a notoriously inhospitable planet, where surface temperatures hover around 860 degrees Fahrenheit (460 Celsius). Travel high into the atmosphere, where it’s cooler, and you’ll find more bearable, even comfortable, temperatures, closer to what we experience on Earth. This is where the telescopes detected the signature of phosphine. But Venus’s atmosphere is so acidic, with clouds made of droplets of sulfuric acid, that any phosphine would be quickly zapped. For the gas to stick around, something must replenish the supply.

Yes, there’s a climate simulation involved and we all know what that means.

Until now, phosphine has been detected only on three other worlds in the solar system. On Earth, it is found in swamps and marshlands, and in the intestines of some animals. On Jupiter and Saturn, the gas is forged within the planets’ violent storms, under extreme conditions that aren’t known to exist anywhere else. Sousa-Silva and the other researchers mimicked similar processes on Venus using computer simulations. They sent jolts of lightning coursing through the atmosphere and meteorites crashing through the clouds. They simulated the scraping of crust against crust, even though Venus doesn’t have plate tectonics, because they couldn’t think of anything else that could produce enough energy to force phosphine into existence.

It’s easy to pooh-pooh the evidence, but having studied microbiology, it’s hard to imagine a whole planet being sterile. The phosphine clue might be a fizzer, but it won’t surprise me if there is some microbial life there. And if there is, I want to see what it uses for DNA. But to get that we need a titanium rocket, or something.

*Edited: Thanks to Bob Fernley-Jones for pointing out that I meant to say clouds and rain specifically are sulphuric acid. The atmosphere is mostly CO2 (of course).

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