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Possible life on Venus?
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raptor1956:
Given the temp on Venus even the most extreme extreme-o-philes would not last long -- seconds at most.  I'm going to go with simply an interesting chemical reaction.

The Fermi paradox still holds.


Brian
CatalinaWOW:
The life hypothesis assumes they exist at high altitudes where temperatures are well within known life ranges.  It would be very exciting if true because it would lend credence to the Asimov proposal to seed the upper Venusian atmosphere with photosynthesizing microbes.  Which would eventually consume the CO2 reducing or ending the greenhouse effect.  Not a short term plan.  Many centuries to start the cooling and many more before planetary surface temperatures would drop to reasonable values, but think of all the real estate.
cdev:

These photos were taken on venus by one of the several Venera space probes.

Gyro:

--- Quote from: CatalinaWOW on September 16, 2020, 02:31:40 am ---The life hypothesis assumes they exist at high altitudes where temperatures are well within known life ranges.  It would be very exciting if true because it would lend credence to the Asimov proposal to seed the upper Venusian atmosphere with photosynthesizing microbes.  Which would eventually consume the CO2 reducing or ending the greenhouse effect.  Not a short term plan.  Many centuries to start the cooling and many more before planetary surface temperatures would drop to reasonable values, but think of all the real estate.

--- End quote ---

^ An important point, the thread would more properly be called 'Possible life above Venus'. The pressures at the surface make it entirely possible for the atmosphere to have its own goldilocks zone at high altitude. Again, with the pressure gradient, it wouldn't be hard for microbes to have sufficient buoyancy to stay there.

It would be very easy to put a buoyant probe into that zone, more or less indefinitely - far easier than putting another very short lived probe on the surface. Once you've put one on the surface, for the achievement / hell of it / to look for big ceramic monsters roaming the surface, there's really no reason to expend the resources to ever go down there again.

https://www.bbc.co.uk/news/science-environment-54133538
donotdespisethesnake:

--- Quote from: Cerebus on September 15, 2020, 08:42:55 pm ---
--- Quote from: donotdespisethesnake on September 15, 2020, 07:30:28 pm ---The sticking points I have with the venus-life hypothesis is in order to survive the 80% sulphuric acid clouds, either:

1) the life forms have a completely different basis to Earth (e.g a non-carbon base). That would be an even more shocking discovery.

2) they have an incredibly tough sealed acid-resistant exterior, like kevlar but stronger. In which case, how do they get nutrients in etc.

--- End quote ---

3) They don't even attempt to survive in the clouds of acid gas, but in some other environmental niche.

If we were observing Earth from Venus we'd be completely unaware of environmental niches that can only be observed from relatively close. From odd micro-environments like black smokers to the whole range of macro-environments that range from tropical rain forest, tundra, permafrost, cold deserts, hot deserts, cave environments and so on. Drawing a broad conclusion from the first environment that can be observed through a telescope with a spectrometer would be short-sighted.

--- End quote ---

Well, the niche the researchers propose is in the clouds 40 km up. There are Hadley cells that circulate a permanent cloud layer, where the clouds are mostly droplets of sulphuric acid. It is possible that the phospine is produced somewhere else and migrates to the cloud layer.



--- Quote ---Also, one has to make allowance for billions of years of evolutionary pressures operating to produce viable organisms. We have bacteria that have evolved on Earth to thrive in the cyanide loaded tailings of gold mining, and in the pH 0 tailings of iron mining, all in the very short period of time, in evolutionary terms, that those processes have been in use - both environments which one would naïvely say were inimical to life as we know it. Also, what's to say that this is ancient life, if indeed it is life, that we're now observing? What's not to say that this is the relatively recent beginnings of life in that environment?

--- End quote ---

Sure that is true. We are basing all our expections of extraterrestrial life, and detection methods thereof, on extrapolations of Earthly life. It could be that life is common, but carbon based life using water as a solvent is just one of many types. Maybe evolution on Earth has not had to try very hard, because most of Earth is quite benign. That may be because life adapts the planet to it's preference - the Gaia principle. However, if Gaia thoery is true, as a corollary of that, we might think that if life on Venus had started when it was benign, them it should have maintained those benign conditions instead of runaway greenhouse effect.

There are so many questions about life and evolution we don't the answer to, it is far too premature to assume life is a cause of unexpected chemistry. Planetary geochemistry is also largely unknown, it is really too simplistic to say "if we find substance X, that means there is a good probability of life". I like the adage "the answer is never life, until it is proven to be life".

There is also an intriguing possibility there borderline life-like processes. Something between prions and viruses. Molecules that can use a catalyst to self-replicate. Logic by itself will not answer these questions. Only studying the environments in more detail will help.

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