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Life on Venus?


Gargamel
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3 hours ago, wumpus said:

Good luck showing that life emerged on Venus: it isn't a place I'd expect to find any fossils.

You don't need fossils to prove Venusian life didn't come from Earth. If the biochemistry and/or nucleotides are different, you can make an assumption that it evolved independently.

3 hours ago, wumpus said:

Panspermia across solar systems would be different from panspermia across planets.  Unless you want to posit that the missing dark matter is extra globs of life being flung through the universe where we assume there is only hydrogen gas.  I can't imagine how much mass it would take to typically seed a galaxy with life (especially if it has to get to a solar system with the first few hundred million years).

I'm talking about life on Venus coming from Earth, nothing to do with intersteller panspermia. If life on Venus is proven to come from Earth, it can't prove much about the rarity of life, as it still only came from one planet in the Solar System's case.

Edited by coyotesfrontier
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1 hour ago, sevenperforce said:

Oxygen is a lifting gas on Venus.

Venus doesn't have much free oxygen, though. The problem with oxygen is that it's rather reactive, and there is a lot of stuff floating around Venus' atmosphere that would just love to bond with it. In fact, that's where the sulfuric acid comes from, CO2 gets split into CO and O by cosmic rays, then O sticks to SO2 to form SO3, and then, when it runs into some water vapor, SO3 grabs a water molecule and makes H2SO4. At the temperatures involved, any O2 would not last much longer than monatomic oxygen before ending up in sulfuric acid.

However, this is a fact that'd be very handy for constructing airship cities. Nitrogen is also a lifting gas over there, so the colony would not need separate lifting and breathing gas envelopes. 

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52 minutes ago, wumpus said:

Good luck showing that life emerged on Venus: it isn't a place I'd expect to find any fossils.  Similarly, I'm not aware of any era in time that fossilization was possible that doesn't contain evidence of life.  Earth life could have easily been seeded by Venus (or any other planet), especially if both planets were under asteroid bombardment (I'm unclear about when this happened vs. when life appeared, but it really only requires one meteror with the exact right exit velocity of debris).

Panspermia across solar systems would be different from panspermia across planets.  Unless you want to posit that the missing dark matter is extra globs of life being flung through the universe where we assume there is only hydrogen gas.  I can't imagine how much mass it would take to typically seed a galaxy with life (especially if it has to get to a solar system with the first few hundred million years).

All life on earth is related, If we find life who is very different as in don't use dna at all or better differ in even more fundamental ways like how amino acids works, better totally other chemistry well its another origin. 

49 minutes ago, sevenperforce said:

No matter how conclusively it is proven that the life originated independently, the sorts of religious groups which deny deep time and think humans put saddles on T. rex will inevitably claim "there are other interpretations".

And so? plenty of weird people, no reason to pay attention to them. 
It would not cause any sort of problems as in more we have today with various fanatics. 
Hint if you want to be weird, some style might earn you respect.
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Edited by magnemoe
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On 9/14/2020 at 8:29 PM, Dragon01 said:

I'm being reminded of a certain thread where I made some bold claims about life in extreme conditions, and quite a few people reacted with disbelief. :) I can't say that I expected that, but I can say that given what we know, the idea is plausible. That said, if this is true, then we're in for some really weird stuff. Extremophiles on Earth are bizarre enough, but Venus? 

TBH, given those results, whatever's causing them would be pretty weird whether it's really life or not. Oh, well, it's an exciting time to be in biophysics. :) I'm currently specializing towards things that happen in humans, but if they really find extraplanetary life I think I'll switch. :) 

At this point, I want to start a bet on how many planets in the Solar System have life... because I have a hunch, a pure hunch, that it's not even two but three.

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1 hour ago, DDE said:

At this point, I want to start a bet on how many planets in the Solar System have life... because I have a hunch, a pure hunch, that it's not even two but three.

I am very pessimistic about Venus cloud life. Martian subsurface life, perhaps.

Gas giant life? I doubt it, but maybe more likely than venusian life, I think it depends on the temperature gradient, and how hot it is when you get deep enough to have much more than hydrogen and helium.

Below the surface of frozen moons, very interesting possibilities.

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2 hours ago, kerbiloid said:

If the Venusian life exists and is a descendant of the Earth one, they can make us to adopt them and take care, or pay.
Do we really need to force the events?

Yes. We can call it "reunification".

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I wonder if the recent study took into account the role phosphonium compounds might play in the Venusian phosphine cycle. Phosphine is a weaker base than ammonia, but it should react quite readily with concentrated sulphuric acid nevertheless. This could mean that phosphine is regularly captured in the clouds and transported with the acid rain into the lower layers of the atmosphere where it would be less susceptible to photochemical reactions.

On the other hand, I don't know if phosphine below the cloud layer would have even been detected by the methods employed in the study in the first place.

 

 

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I would say that's a priority, on Mars there is also a lot of talk about eventually returning samples. A rover can do much less than a human in a lab, and if there is something in there, we'd like to get a good look. 

Returning samples in a way that prevents contamination is a challenge, but it can be done and I'd say it has to. The only other way, bringing humans to Mars and Venus, is harder.

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10 minutes ago, Dragon01 said:

I would say that's a priority, on Mars there is also a lot of talk about eventually returning samples. A rover can do much less than a human in a lab, and if there is something in there, we'd like to get a good look. 

Returning samples in a way that prevents contamination is a challenge, but it can be done and I'd say it has to. The only other way, bringing humans to Mars and Venus, is harder.

I wonder if theoretically it would make sense to do a potentially biohazardous sample return to the ISS.

On the one hand they have fewer containment measures. On the other hand they are one gigantic containment measure.

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The main concern with alien life forms is that they're not contaminated with Earth ones, not the other way around. Alien life would be adapted to alien conditions. In particular, an atmosphere not full of a ridiculously powerful oxidizer.

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2 minutes ago, Dragon01 said:

The main concern with alien life forms is that they're not contaminated with Earth ones, not the other way around. Alien life would be adapted to alien conditions. In particular, an atmosphere not full of a ridiculously powerful oxidizer.

Still, we kept the Apollo astronauts in quarantine for three weeks.

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In the 60s, back before we knew much about anything that wasn't Earth, and our understanding of Earth wasn't as extensive as it's now, either. Also, I think this was only the case with Apollo 11. At any rate, we know better now.

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2 hours ago, DDE said:

 

Nice but don't get how the blue cylinder expand. 
Would not land like that either but might use heat shield as landing legs and balast, robotic arm in front to collect samples. 
Start to inflate an 80 bar balloon able to survive high tempratures, the expanding gas would provide cooling. 
After getting the samples and balloon if full enough release from the heat shield and the arm. 
As you get higher  you unfold the second balloon who is thinner and could not handle the high temperature. Then all helium is in balloons and temperature outside is not an issue drop the protective shell, the helium tanks and the mechanism for loading the rocket. Probably have the rocket pointing down to make this easier. use an rail and cable to point it up. 
Drop it and have it reach low orbit. It would be much like an small air launched rocket on earth. Stuff in orbit == Mars sample return. 

11 minutes ago, Dragon01 said:

The main concern with alien life forms is that they're not contaminated with Earth ones, not the other way around. Alien life would be adapted to alien conditions. In particular, an atmosphere not full of a ridiculously powerful oxidizer.

This, earth life is so diverse you might end up bringing some weird spores who could survive on Mars at least if you do stuff like drilling. 
And bringing humans to Mars will contaminate it. 
On the other hand its just about finding who earth microbe it is. Even if earth microbes came to mars 250 million years ago they would be very different now. 

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A surface sample mission isn't really needed for finding atmospheric life, it would add extra complexity and danger to a mission.  As Venus is resurfaced by volcanic activity every few millions of years, you would have to drill really deep and in just the right place to search for microfossils.

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No, but it is needed for finding possible non-biological explanations for the origins of phosgene. This also needs to be considered, we don't really know where exactly to look in the clouds, and even if there really is something alive up there. We need to know more about the surface, too.

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Maybe something similar to the most aerodynamic satellite we ever launched?

https://en.wikipedia.org/wiki/Gravity_Field_and_Steady-State_Ocean_Circulation_Explorer

It managed to stay at low, low altitude of 250 kilometers for four years.

One above Venus could skim the upper layers of atmosphere for maybe a year or two, gathering samples in the hope of picking up some spores (if any would be present).

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On 9/15/2020 at 3:29 AM, Dragon01 said:

It wouldn't. There are several forms of life that live in volcanic springs and other extremely acidic environments. In fact, those very organisms can usually tolerate high temperatures, too.

KerikBalm already mentioned that Venus is way too dry for any life we know of to grow and replicate. It's also the case that the acidity of the sulfuric acid droplets is at least 10^11 times more acidic than the most acidic place on Earth where we might find life (which has negative pH). In fact, the pH scale doesn't even make sense here because it's not dilute enough. https://www.liebertpub.com/doi/10.1089/ast.2020.2244

 

This precludes any life similar to what we know about. This means if there is life, it would have to be completely different, having arisen through independent abiogenesis. But presents a bit of a dilemma since we can't use phosphine as a biosignature for any unknown life. It's suitability as a biomarker is based only on known anaerobic life.

 

So this discovery doesn't increase my probability for life, except in the sense that "we found something in space that we can't explain" (big surprise), and it could be anything.

 

Here is a quote from a preprint paper written by most of the same authors as the original discovery paper:

"We conclude that, while we cannot rule out life as a source of the phosphine on Venus, the hypothesis that the phosphine is produced by life cannot a priori be favored over the hypothesis of unknown photochemistry or unknown atmospheric chemistry. All seem equally unlikely, and hence all call for further investigation. We note, after (Catling et al. 2018), that the extraordinary claim of life should be the hypothesis of last resort only after all conceivable abiotic alternatives are exhausted."

https://arxiv.org/abs/2009.06499

 

The most likely explanation is that our models and estimates are wrong. We have seriously limited information about Venus. We don't even know the composition of crust and mantle rocks, although all the plausible types based on what is known about rocky planets in general were considered. 

 

There is the extremely slim chance that life arose when Venus was much nicer and had water oceans up to 4 billion years ago. My favorite wild speculative theory is that there used to be a civilization on Venus much like ours, but they destroyed themselves through nuclear war and global warming, leading to the current runaway greenhouse atmosphere. Volcanic activity caused magma to ignite abundant fossil fuel deposits leading to the formation of phosphorous-rich pyrometamorphic rocks (like zuktamrurite). The above paper briefly mentions these types of rocks as a source of phosphorus.

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