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#20
by
FutureSpaceTourist
on 14 Sep, 2020 15:54
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https://threadreaderapp.com/thread/1305521729662529536.html A team led by @jgreaves6 have found what might be signs of life high in Venus' atmosphere. They have detected phospine, a gas which on Earth is produced only by life, in quantities they say are too large to be produced any other way. (1/17)
The discovery was made by using sub-mm (microwave) telescopes @eao_jcmt and @almaobs; phosphine is detected roughly 50km above the surface; parts of the atmosphere have temperature and pressure similar to sea level on Earth (2/17)
The phosphine exists at about 20 parts per billion, which doesn't sound much but which the team's modelling says is ten thousand times more than can be produced by volcanic activity or atmospheric chemistry. Their conclusion - this could be life. (3/17)
Is this real? Firstly, I'm told there has been much skepticism, including from journal referees, about the detection. JCMT and Alma were not made to look at things as bright as Venus and this is a difficult observation. (4/17)
However, we have detections from two seperate telescopes, and the team who led the data reduction - @jgreaves6 and Anita Richards at @UoMPhysics - know JCMT and Alma very well. I'd bet the detection is real. (5/17)
(Side note - @PlanetaryColin reminded me yesterday that the Russian Vega descent probes found - confusingly - that the lower clouds of Venus had lots of Phosphorus. They didn't test its form, and people assumed it would be phosphoric acid, not phosphine) (6/17)
Is phospine a sign of life? It's only produced by life - in strange places like penguin guts - on Earth, and though its seen in the atmospheres of Jupiter and Saturn there its created by pressure-driven chemistry that can't be happening on Venus. (7/17)
The team - particularly William Bains, along with Helen Fraser at the OU and others - have built a model that tries to keep track of the many chemical reactions that might produce phospine. They can't get it to account for what's seen. (8/17)
The details of that model are in a second paper which has not yet been accepted by the journal, and it will be heavily scrutinised when it comes out! There are two possibilities. Either the team have missed something obvious or made a mistake... (9/17)
..Or studying the chemistry of Venus' atmosphere just became a very hot topic. Reactions in a sulphuric acid rich environment are, I suspect, not well understood. It will be fascinating to watch what happens. My bet is on chemistry (#itsneveraliens) but who knows! (10/17)
(Worth noting that my go-to expert on solar system chemistry @PlanetDr is highly skeptical, and posted this earlier, which is wise:) (11/17)
If it is life, it must be very unusual life. There are microorganisms adapted to very acidic environments on Earth, but nothing like this. There are also ideas about how a life cycle could work, published by 's team: discovermagazine.com/the-sciences/h… (12/17)
If it is life, then the prospects of life being widespread in the cosmos increases rapidly. If life can evolve and survive on Venus, I suspect we should expect it in a much wider range of environments than previously thought. (13/17)
So what's next? I'm sure there will be repeated observations. Understanding if the detection is real, and whether the amount of phospine changes with time will be crucial. (14/17)
What about spacecraft? None of the planned orbiters will have instruments which will help. Proposed entry probes (American DAVINCI+, Russian Venera-D) will measure the composition but will plunge through the atmopshere fast. (15/17)
What's needed is something like the proposed Venus Flagship Mission which would have a balloon floating in the atmosphere, capable of looking for biomolecules. Balloning on Venus (though probably in the 2030s)! vfm.jpl.nasa.gov (16/17).
So there's much work to do to understand what this result means, but it's fascinating. If you're in the UK, you can hear the full story from @jgreaves6 and her team on #skyatnight, BBC4, 10.30pm tonight (17/17)
One final thing - I've been trying to think how this compares to other moments. I think what's different here is that the team went looking for phospine in order to search for life - and found it. That's a remarkable result whichever way you look at it (18/17)
(A certain vintage of British astronomer will be pleased to know that one version of the story of how this discovery came about features conversations in Uncle Billy's in Hilo). (19/17)
https://twitter.com/chrislintott/status/1305521729662529536https://twitter.com/chrislintott/status/1305521841545637888https://twitter.com/chrislintott/status/1305521961888604160https://twitter.com/chrislintott/status/1305522111704969222https://twitter.com/chrislintott/status/1305522230944768000https://twitter.com/chrislintott/status/1305522350713118720https://twitter.com/chrislintott/status/1305522475002982400https://twitter.com/chrislintott/status/1305522594721026050https://twitter.com/chrislintott/status/1305522690468581378https://twitter.com/chrislintott/status/1305522830843539457
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#21
by
Orbiter
on 14 Sep, 2020 15:56
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Expect to see a flood of skepticism from astronomers and planetary scientists. That's very good, because it shows the scientific method in work. If the evidence still stands in a few years, we may see a mission to Venus on the table.
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#22
by
Star One
on 14 Sep, 2020 16:12
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Well it’s not so much outright scepticism I’ve seen so far but a great deal of caution. But I think this points out the importance of in situ studies through missions to the planet.
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#23
by
Frogstar_Robot
on 14 Sep, 2020 16:23
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A lot of "we don't knows" in that presser. Champagne back in cellar for now. On the one hand, they say phosphine can be produced by life on Earth, but then that life couldn't possibly survive on Venus.
If finding extraterrestrial life is the peak, we are still in the foothills of a discovery.
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#24
by
trm14
on 14 Sep, 2020 16:24
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A strong note of caution over this result.
Still, John Carpenter, an ALMA observatory scientist, is skeptical that the phosphine observations themselves are real. The signal is faint, and the team needed to perform an extensive amount of processing to pull it from the data returned by the telescopes. That processing, he says, may have returned an artificial signal at the same frequency as phosphine. He also notes that the standard for remote molecular identification involves detecting multiple fingerprints for the same molecule, which show up at different frequencies on the electromagnetic spectrum. That’s something that the team has not yet done with phosphine.
“They took the right steps to verify the signal, but I’m still not convinced that this is real,” Carpenter says. “If it’s real, it’s a very cool result, but it needs follow-up to make it really convincing.”
https://api.nationalgeographic.com/distribution/public/amp/science/2020/09/possible-sign-of-life-found-on-venus-phosphine-gas
It's quite unusual that a staff scientist at an observatory that was used in the detection is so openly sceptical. He should certainly know ins and outs of ALMA data reduction.
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#25
by
Star One
on 14 Sep, 2020 16:24
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A lot of "we don't knows" in that presser. Champagne back in cellar for now. On the one hand, they say phosphine can be produced by life on Earth, but then that life couldn't possibly survive on Venus.
If finding extraterrestrial life is the peak, we are still in the foothills of a discovery.
Not sure where you get the idea that life couldn’t possibly exist on Venus, that might be true of its surface now. But that wasn’t the case up until 750 million years ago, and it isn’t true possibly of the atmosphere today.
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#26
by
Star One
on 14 Sep, 2020 16:25
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A strong note of caution over this result.
Still, John Carpenter, an ALMA observatory scientist, is skeptical that the phosphine observations themselves are real. The signal is faint, and the team needed to perform an extensive amount of processing to pull it from the data returned by the telescopes. That processing, he says, may have returned an artificial signal at the same frequency as phosphine. He also notes that the standard for remote molecular identification involves detecting multiple fingerprints for the same molecule, which show up at different frequencies on the electromagnetic spectrum. That’s something that the team has not yet done with phosphine.
“They took the right steps to verify the signal, but I’m still not convinced that this is real,” Carpenter says. “If it’s real, it’s a very cool result, but it needs follow-up to make it really convincing.”
https://api.nationalgeographic.com/distribution/public/amp/science/2020/09/possible-sign-of-life-found-on-venus-phosphine-gas
It's quite unusual that a staff scientist at an observatory that was used in the detection is so openly sceptical. He should certainly know ins and outs of ALMA data reduction.
I thought it was odd. Maybe he didn’t agree with the paper going out now?
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#27
by
Star One
on 14 Sep, 2020 16:26
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#28
by
Frogstar_Robot
on 14 Sep, 2020 16:30
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A lot of "we don't knows" in that presser. Champagne back in cellar for now. On the one hand, they say phosphine can be produced by life on Earth, but then that life couldn't possibly survive on Venus.
If finding extraterrestrial life is the peak, we are still in the foothills of a discovery.
Not sure where you get the idea that life couldn’t possibly exist on Venus, that might be true of its surface now. But that wasn’t the case up until 750 million years ago, and it isn’t true possibly of the atmosphere today.
You misunderstand, they said that carbon-based life that exists on Earth *now*, could not exist on Venus *now* because it would be ripped apart by sulphuric acid etc. Earth life and Venus life would have to have evolved along completely different metabolic pathways for venus-life to exist *now*.
Therefore, the assumption that because current Earth based life can produce phosphine, this is also true for Venus, does not hold since Venus life cannot be similar to Earth life.
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#29
by
Alpha_Centauri
on 14 Sep, 2020 16:38
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A lot of "we don't knows" in that presser. Champagne back in cellar for now. On the one hand, they say phosphine can be produced by life on Earth, but then that life couldn't possibly survive on Venus.
If finding extraterrestrial life is the peak, we are still in the foothills of a discovery.
Not sure where you get the idea that life couldn’t possibly exist on Venus, that might be true of its surface now. But that wasn’t the case up until 750 million years ago, and it isn’t true possibly of the atmosphere today.
You misunderstand, they said that carbon-based life that exists on Earth *now*, could not exist on Venus *now* because it would be ripped apart by sulphuric acid etc. Earth life and Venus life would have to have evolved along completely different metabolic pathways for venus-life to exist *now*.
Therefore, the assumption that because current Earth based life can produce phosphine, this is also true for Venus, does not hold since Venus life cannot be similar to Earth life.
The point is the metabolic pathways may be similar, not necessarily everything else about these organisms. The suggestion (and this seems really not well understood right now) is that phosphine production is a feature amongst some anaerobes on Earth. The claim is the same anaerobic pathway (which again we don't know much about) may be used on Venus.
This all hinges on three things right now. Have they definitely detected phosphine? What is the nature of Phosphine biochemistry? Can we definitely rule out geo-/photochemistry? I feel these all need much better answers than we have now.
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#30
by
ugordan
on 14 Sep, 2020 16:41
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#31
by
Alpha_Centauri
on 14 Sep, 2020 16:54
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#32
by
sghill
on 14 Sep, 2020 17:37
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I only have one question: Why are the penguins and badgers making phosphine? I.E. what in their diet or metabolism causes phosphine to be present in their systems?
Start there, and look for commonality with the venusean environment.
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#33
by
Welsh Dragon
on 14 Sep, 2020 17:43
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I only have one question: Why are the penguins and badgers making phosphine? I.E. what in their diet or metabolism causes phosphine to be present in their systems?
Start there, and look for commonality with the venusean environment.
They aren't, their gut microbiota do.
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#34
by
Star One
on 14 Sep, 2020 18:33
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This news is covered on tonight’s edition of The Sky at Night 22:30 UK time on BBC Four.
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#35
by
Danirode
on 14 Sep, 2020 18:39
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Sooo.... do we already have a tread speculating on a sample return mission? Just sayin'...
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#36
by
Star One
on 14 Sep, 2020 18:51
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#37
by
Orbiter
on 14 Sep, 2020 19:06
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I'm surprised there's not more interest in this. Skepticism is warranted, but this is probably the strongest signal for extraterrestrial life we've ever had. Granted, the bar there was quite low, but still...
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#38
by
FutureSpaceTourist
on 14 Sep, 2020 19:07
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#39
by
Star One
on 14 Sep, 2020 19:07
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I'm surprised there's not more interest in this. Skepticism is warranted, but this is probably the strongest signal for extraterrestrial life we've ever had. Granted, the bar there was quite low, but still...
I think people have been burnt once to often in the past. Looking at you Martian meteorite.