> I see no reason why intelligent life with high technology could not have developed on Venus. Say, several hundred million years ago. And perhaps they triggered runaway greenhouse warming, which vaporized the oceans. And so perhaps it was the loss of the oceans that ended plate tectonics, not the other way around.
The only way that thought experiment could make sense is if they had the technology to do that, but not the technology to escape Venus and get to Earth.
Think about it; several hundred million years ago, Earth was habitable; maybe not for modern humans (but I bet we could do it - though uncomfortably), but definitely life existed in some form:
So there was liquid water, and the Earth wasn't a Dante-esque hellscape of volcanos and lava, etc. It was probably much warmer and more humid, but overall not crazy to live on.
So if your situation was dire enough, and you had the technology to escape the planet (which you'd almost have to, if you had the energy resources to cause your own global warming and demise scenario) - wouldn't you at least try?
So either they tried and failed in some manner (never reaching Earth), or they succeeded (meaning?) or something in between.
Even if they didn't try, with the level of technology, wouldn't they at least have left something behind in the solar system that we'd recognised as created by intelligent life long ago? Some artifact somewhere?
Maybe they did, and we haven't found it (space is big - the solar system is a big place); but I'd almost expect there'd be something orbiting Venus that was artificial (though maybe again, we can't detect it from here - too small, likely inactive, etc). I guess a good question would be, if you were on Venus (or even in Venusian orbit) - could you detect Earth's satellites currently orbiting Earth? Could you detect a singular one (last of its kind) in a degraded, virtually inert state? Again, I don't know.
It's a bit fascinating to think about; part of me wants to say "we should be able/have found something by now" if such a scenario were real - but at the same time, I can think of reasons why we haven't or can't...
Pure speculation, but agriculture or the the equivalent of the industrial revolution might have been enough to create a runaway greenhouse effect. I find it easy to imagine how our civilization could have gone extinct due to fossil fuel use without ever getting anything close to orbital velocity.
The only way that thought experiment could make sense is if they had the technology to do that, but not the technology to escape Venus and get to Earth.
If you have the technology to do that, but don't have the civilization infrastructure to support it, then escape/colonization might well cease to be a viable option. A global warming catastrophe could well precipitate a collapse of global civilization, in precisely the initially slow, sneaking way which might catch a global civilization unprepared. The Romans knew things were breaking down, but the generation which was invaded by the Vandals didn't think it was quite that time yet. Global civilization might well kick the can down the road with building their sun-shield, then get caught with its pants down, when civilization starts crumbling, and it loses the industrial know-how to pull it off.
How about a downer Sci-fi story, where the closing scene is of a Flat-Venuser enclave surviving in a subvenusian tunnel, telling half understood mythological stories of the long dead Eloi and their plot to blot out the sun?
> The only way that thought experiment could make sense is if they had the technology to do that, but not the technology to escape Venus and get to Earth.
Maybe they DID get to Earth, and are currently busy transforming our atmosphere to generate cozier conditions for themselves?
"In his house at R'lyeh dead Cthulhu waits dreaming."
But seriously, an invasion from Venus a billion years ago would leave no evidence we could reconstruct today. After they went extinct, less than a million years later, their microbes would remain. And eventually become us.
That's the most interesting possibility, I think. Probably not just "become us", though, because there's evidence for eukaryotic life, well before then. But it's only fuzzy structural and geochemical evidence. So they and/or their microbes could have merged.
However, the Earth wasn't so hospitable, ~1000 Ma BP. There wasn't much free oxygen then. Not until 600-800 Ma BP, I gather. So if they were oxygen breathers, they would have been living in habitats. But maybe they made the move ~600 Ma BP. That would have been ~endgame on Venus.
I don't see how any of this is testable, however. Some have argued that Octopodidae aren't originally from Earth. But it's iffy.[0] Still, who knows? Maybe they did come from Venus ;)
> if you were on Venus (or even in Venusian orbit) - could you detect Earth's satellites currently orbiting Earth?
Inverting it, we could probably not detect any artificial satellite on Venus here from Earth. But we've had launched satellites there, that should be able to detect other ones if they have a good camera (because satellites shine).
So, the question becomes, does any of the satellites there has a good enough camera?
The only way that thought experiment could make sense is if they had the technology to do that, but not the technology to escape Venus and get to Earth.
Think about it; several hundred million years ago, Earth was habitable; maybe not for modern humans (but I bet we could do it - though uncomfortably), but definitely life existed in some form:
https://en.wikipedia.org/wiki/Age_of_the_Earth
So there was liquid water, and the Earth wasn't a Dante-esque hellscape of volcanos and lava, etc. It was probably much warmer and more humid, but overall not crazy to live on.
So if your situation was dire enough, and you had the technology to escape the planet (which you'd almost have to, if you had the energy resources to cause your own global warming and demise scenario) - wouldn't you at least try?
So either they tried and failed in some manner (never reaching Earth), or they succeeded (meaning?) or something in between.
Even if they didn't try, with the level of technology, wouldn't they at least have left something behind in the solar system that we'd recognised as created by intelligent life long ago? Some artifact somewhere?
Maybe they did, and we haven't found it (space is big - the solar system is a big place); but I'd almost expect there'd be something orbiting Venus that was artificial (though maybe again, we can't detect it from here - too small, likely inactive, etc). I guess a good question would be, if you were on Venus (or even in Venusian orbit) - could you detect Earth's satellites currently orbiting Earth? Could you detect a singular one (last of its kind) in a degraded, virtually inert state? Again, I don't know.
It's a bit fascinating to think about; part of me wants to say "we should be able/have found something by now" if such a scenario were real - but at the same time, I can think of reasons why we haven't or can't...