Study: Probability of extraterrestrials in the Milky Way low
heise.de> The probability of two civilizations with highly developed technology existing simultaneously in the Milky Way is so low that another would have to be at least 280,000 years old to exist alongside us now. At least, that is what two researchers from the Austrian Academy of Sciences have calculated, based on their estimates of how many rocky planets with plate tectonics and an atmosphere of nitrogen and oxygen appear to exist.
Oh man, I have about 200 science fiction books to recommend to these guys.
To summarze: Extraterrestrial life doesn't have to be just like us. It could very well be aquatic, it could very well be post-biological in any of a million different ways. (See, e.g., Accelerando.) We don't even know if there's life on Ganymede; it's absolutely absurd -- frankly, it hardly even seems sane -- to rule out extraterrestrial life in the Milky Way on such shaky and unimaginative grounds.
You're missing out on key phrase "highly developed technology". Science fiction books are fiction, it's right in the name. They do offer some nice explorations of ideas and some are based on sound scientific principles I can assure you that none of them talking about advanced extraterrestrial life are built upon any known scientific testable principles that we have today.
Talking about Ganymede, if there was highly developed extraterrestrial life on par with technology within 100 years of ours we would have detected it. Nothing about what they say excludes undeveloped extraterrestrial life or microorganisms.
Aquatic life, we have examples of intelligent aquatic life on this planet but that life does not fit the "highly developed technology" requirement. We don't know how intelligent the aquatic life is but we know it is intelligent and appears to be self-aware.
Is the development of technology a key factor in determining intelligence? That seems like a philosophical question more than a scientific question but not having the answer to that does not negate the calculations that were made which require highly developed technology of two or more civilizations simultaneously.
If we don't destroy ourselves, mankind is perhaps 100 years from going post-human, post-biological. At a relatively early stage in our technological development -- ~10,000 years since developing agriculture -- we're leaving behind the paradigm where we require biomarkers that are (supposedly) common to Earthlike life. A "highly developed technological society" is unlikely to require plate tectonics, lol.
Ganymede's an extreme example as it's quite literally next door, and we still have absolutely no idea what swims in its 60-mile-deep oceans, save to say that they're not shooting lasers through the ice or launching satellites. Do you know from what distance we'd be able to detect an Earthlike planet with extraterrestrials who are at a current-Earth tech level?
> none of them talking about advanced extraterrestrial life are built upon any known scientific testable principles that we have today.
And what testable principles are those?
Last I checked, biopoiesis is an unsolved problem, and chemical space is extremely vast -- there are many different ways to organize CHONS life, and there are also ways to organize other forms of life entirely.
Surely "they have to be just like us" is one of the most annoying scientific fallacies.
Extraordinary claims require extraordinary evidence. What evidence do you have that we are 100 years from going post-human or post biological? Technology is fascinating but all of the technology that we have ever created has not even come close to the complexity of the most simple biology. All existing evidence is that biological life is far more complex, and adaptable, than any technological creation that can be made. While scientists understand these biological compounds It has alluded them on how to organize them into even the most simple microbe that we know about.
The far more likely thing is that in the next hundred years we will see our crude technology come to mimic biology.
So you're talking about an unsolved problem that has no evidence pointing to any solution. You're claiming there are different ways to organize life but where is the evidence there is different ways to organize life than what we have seen? That's how you formulate a hypothesis and then you begin to test it. Without that you're simply speaking fantasy. There are definitely unknowns but all the evidence points to life would be like us in the generic sense that it is biological and based upon similar biological compounds. It's form may take different shapes It's perception maybe things that we don't understand yet but there is zero evidence of life being capable organizing itself around a completely foreign system than what we've seen.
I welcome research in that direction to show that life can be organized around fundamentally different things than what we've seen but fantastical ideas from science fantasy stories do not help actual research happen.