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| Possible life on Venus? |
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| Cerebus:
--- Quote from: donotdespisethesnake on September 16, 2020, 11:14:36 am --- 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. --- End quote --- I think you're having a problem here because you're making quite reasonable hypotheses on one hand, and holding a bunch of interfering assumptions on the other. The assumption that Earth is benign is a wrong assumption to make. From the perspective of a different biochemistry 300ºK and a 20% oxygen atmosphere might be anything but benign - way too hot, way too cold. Heck, from the perspective of Earth biochemistry that highly reactive 20% oxygen atmosphere is anything but benign, why do you think every life form on Earth is riddled with antioxidants? Life here has evolved to make use of that oxygen atmosphere but if you were choosing a system to work under, you wouldn't choose one where one spark makes the difference between a tree living and going up in flames and every organism has to protect itself against the atmosphere it lives in. However, evolution managed to cope with such a nastily reactive, poisonous atmosphere and even turned it to advantage - having such a large pool of redox potential available (atmospheric oxygen) is why terrestrial creatures can move so fast. --- Quote ---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. --- End quote --- The reactions that cause people to suggest life as a possible explanation are ones where the reactions are going uphill energetically when, from a simple chemistry perspective, you'd expect them to be going downhill. The blindly obvious one on Earth is the formation of free atmospheric oxygen when all the chemical expectations are that under Earth-like conditions oxygen binds to something and then stays there. The only place you see these reactions happen 'uphill' on Earth is where life is involved and it's a reasonable tack to be taking to search for life as we understand it to be, even if it was life that could be in many ways different from terrestrial life. In fact, in this context, it's probably the most useful working definition of what constitutes "life". --- Quote from: donotdespisethesnake on September 16, 2020, 11:14:36 am ---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. --- End quote --- You do know what an enzyme is, don't you? That's pretty much the basis of life on Earth, enzymes are molecules that can catalyse very specific (usually energetically unfavourable) chemical reactions to create or modify the building blocks of life. |
| Mr. Scram:
--- Quote from: Cerebus on September 15, 2020, 08:42:55 pm ---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. 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 --- Exactly. We've been caught out by extremophiles on Earth, upturning our views and beliefs. There's no saying what conditions Venus could serve up and how life may have adapted, whether that's carbon based or anything else. |
| Mr. Scram:
--- Quote from: raptor1956 on September 16, 2020, 02:14:25 am ---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 --- End quote --- We felt the same about extremophiles we didn't know about before. Yet they popped up and somehow filled their niche. |
| donotdespisethesnake:
--- Quote from: Cerebus on September 16, 2020, 01:10:04 pm ---You do know what an enzyme is, don't you? --- End quote --- No, I have no fucking clue, because I am a fucking moron. Of course I know what a fucking enzyme is! But thanks for your patronizing comments, it really helps the discussion. |
| TimFox:
Unfortunately, I never saw the episodes (69 and 70) of the TV show "The Six Million Dollar Man" that had an interesting synopsis: A Russian planetary probe, designed for a soft landing on Venus with extraordinary survival capability due to a super-alloy, gets loose in Wyoming and the superhero is required to stop its rampage. |
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