• Is there life floating in the clouds of Venus?

    From alexander koryagin@2:5020/2140.2 to All on Mon Oct 5 14:26:32 2020
    Hi, All!

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    Is there life floating in the clouds of Venus?
    By Jonathan Amos
    BBC Science Correspondent

    It's an extraordinary possibility - the idea that living organisms are floating in the clouds of Planet Venus.

    But this is what astronomers are now considering after detecting a gas
    in the atmosphere they can't explain.

    That gas is phosphine - a molecule made up of one phosphorus atom and
    three hydrogen atoms.

    On Earth, phosphine is associated with life, with microbes living in the
    guts of animals like penguins, or in oxygen-poor environments such as
    swamps.

    For sure, you can make it industrially, but there are no factories on
    Venus; and there are certainly no penguins.

    So why is this gas there, 50km up from the planet's surface? Prof Jane Greaves, from Cardiff University, UK and colleagues are asking just this question.

    They've published a paper in the journal Nature Astronomy detailing
    their observations of phosphine at Venus, as well as the investigations they've made to try to show this molecule could have a natural,
    non-biological origin.

    But for the moment, they're stumped - as they tell the BBC's Sky At
    Night programme, which has talked at length to the team. You can see the
    show on BBC Four tonight (Monday) at 22:30 BST.

    Given everything we know about Venus and the conditions that exist
    there, no-one has yet been able to describe an abiotic pathway to
    phosphine, not in the quantities that have been detected. This means a
    life source deserves consideration.

    "Through my whole career I have been interested in the search for life elsewhere in the Universe, so I'm just blown away that this is even
    possible," Prof Greaves said. "But, yes, we are genuinely encouraging
    other people to tell us what we might have missed. Our paper and data
    are open access; this is how science works."


    What exactly has the team detected?

    Prof Greaves' team first identified phosphine at Venus using the James
    Clerk Maxwell Telescope in Hawaii, and then confirmed its presence using
    the Atacama Large Millimeter/submillimeter Array in Chile.

    Phosphine has a distinctive "absorption line" that these radio
    telescopes discern at a wavelength of about 1mm. The gas is observed at mid-latitudes on the planet at roughly 50-60km in altitude. The
    concentration is small - making up only 10-20 parts in every billion atmospheric molecules - but in this context, that's a lot.


    Why is this so interesting?

    Venus is not at the top of the list when thinking of life elsewhere in
    our Solar System. Compared to Earth, it's a hellhole. With 96% of the atmosphere made up of carbon dioxide, it has experienced a runaway
    greenhouse effect. Surface temperatures are like those in a pizza oven -
    over 400C.

    Space probes that have landed on the planet have survived just minutes
    before breaking down. And yet, go 50km up and it's actually
    "shirtsleeves conditions". So, if there really is life on Venus, this is exactly where we might expect to find it.



    Why should we be sceptical?

    The clouds. They're thick and they're mainly composed (75-95%) of
    sulphuric acid, which is catastrophic for the cellular structures that
    make up living organisms on Earth.

    Dr William Bains, who's affiliated to the Massachusetts Institute of Technology (MIT) in the US, is a biochemist on the team. He's studied
    various combinations of different compounds expected to be on Venus;
    he's examined whether volcanoes, lightning and even meteorites could
    play a role in making PH3 - and all of the chemical reactions he's investigated, he says, are 10,000 times too weak to produce the amount
    of phosphine that's been observed.

    To survive the sulphuric acid, Dr Bains believes, airborne Venusian
    microbes would either have to use some unknown, radically different biochemistry, or evolve a kind of armour.

    "In principle, a more water-loving life could hide itself away inside a protective shell of some sorts inside the sulphuric acid droplets," he
    told Sky At Night. "We're talking bacteria surrounding themselves by
    something tougher than Teflon and completely sealing themselves in. But
    then how do they eat? How do they exchange gases? It's a real paradox."


    What's been the reaction?

    Cautious and intrigued. The team emphatically is not claiming to have
    found life on Venus, only that the idea needs to be further explored as scientists also hunt down any overlooked geological or abiotic chemical pathways to phosphine.

    Oxford University's Dr Colin Wilson worked on the European Space
    Agency's Venus Express probe (2006-2014), and is a leading figure in the development of a new mission concept called EnVision. He said Prof
    Greaves' observations would spur a new wave of research at the planet.

    "It's really exciting and will lead to new discoveries - even if the
    original phosphine detection were to turn out to be a spectroscopic misinterpretation, which I don't think it will. I think that life in
    Venus' clouds today is so unlikely that we'll find other chemical
    pathways of creating phosphine in the atmosphere - but we'll discover
    lots of interesting things about Venus in this search," he told BBC News.

    Prof Lewis Dartnell from the University of Westminster is similarly
    cautious. He's an astrobiologist - someone who studies the possibilities
    of life beyond Earth. He thinks Mars or the moons of Jupiter and Saturn
    are a better bet to find life.

    "If life can survive in the upper cloud-decks of Venus - that's very illuminating, because it means maybe life is very common in our galaxy
    as a whole. Maybe life doesn't need very Earth-like planets and could
    survive on other, hellishly-hot, Venus-like planets across the Milky Way."


    How can the question be resolved?

    By sending a probe to investigate specifically the atmosphere of Venus.

    The US space agency (Nasa) asked scientists recently to sketch the
    design for a potential flagship mission in the 2030s. Flagships are the
    most capable - and most expensive - ventures undertaken by Nasa. This particular concept proposed an aerobot, or instrumented balloon, to
    travel through the clouds of Venus.

    "The Russians did this with their Vega balloon (in 1985)," said
    team-member Prof Sara Seager from MIT. "It was coated with Teflon to
    protect it from sulphuric acid and floated around for a couple of days,
    making measurements.

    "We could definitely go make some in-situ measurements. We could
    concentrate the droplets and measure their properties. We could even
    bring a microscope along and try to look for life itself."

    https://www.bbc.com/news/science-environment-54133538
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    Bye, All!

    Alexander Koryagin

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