There has been a longstanding interest in whether humans are alone in the Universe, or there are other alien intelligences out there. Initially there was a question of whether our solar system was one of a kind; this has been definitively answered by detecting planets around many nearby stars. Then there is a question of whether life itself is a fluke or is common; this is still uncertain, but there is increasing understanding of processes by which life could have originated from non-living precursors. Then there is a question of whether, if life does turn out to be relatively common on other planets, such life could develop forms of intelligence similar to that of humans. And, finally, if intelligent life exists in other planetary systems, whether we could become aware of it on the basis of things humans could observe—for example, by detecting radio transmissions.
Unfortunately, there are a number of considerations to take into account when we think about looking for extraterrestrial intelligent life in this way.
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- Intelligent technological civilizations on other star systems may exist, but not at the same time as humans. They either were before our time, or haven’t yet come into being. The Universe has existed for something over 14 billion years, which is a very long time for there to be simultaneity.
- Humans have only existed in modern anatomical form for about 250,000 years.
- Humans have only started doing agriculture and living in permanent settlements for about 10,000 years.
- Humans have only had fuel energy-powered technology for about 300 years.
- Humans have only been transmitting radio waves at a power level that could be observed by other civilizations for about 100 years.
Remember, if humans detect a radio signal from a star system 1,000 light years away, the signal was transmitted 1,000 years ago.
Intelligent technological civilizations may only exist for a limited time and then disappear, due to a number of possibilities.
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- They use up their planet’s non-renewable natural resources.
- They make their planet uninhabitable through pollution, global climate change or ozone depletion, or something else we haven’t encountered yet.
- They kill each other off via warfare (e.g., using nuclear or biological agents).
- They succumb to pathogens they can’t overcome.
- They suffer an accumulation of genetic defects due to lack of selection processes.
It is a major question how long we think human technological civilization is likely to last. It might be just a blink of an eye, in cosmic time. Truly, will we still be around in, say, 10,000 years?
Intelligent technological civilizations on other star systems may only use such high technology as humans could observe for a limited time before they give it up. Some examples include
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- Travel in space. The low-hanging fruit in their own solar system may be picked quickly. Then interstellar space is too vast to explore in a practical way.
- High-power electromagnetic radiation. Note that human radio and television broadcasting is already going away for other more efficient means of distributing information.
Human sustainability for the really long term might involve remarkably little high-resource technology.
Intelligent species on other star systems may not have evolved human-equivalent manipulative capabilities, such as bipedalism with extraordinarily dexterous hands, to be able to create human-observable technologies. Note that highly intelligent animal lines on earth such as elephants, cetaceans, and corvids aren’t going to evolve such manipulation capabilities.
So finding similar intelligences out there with whom to interact and get help may be extraordinarily difficult. We probably are going to have to solve our problems on our own.
You raise fascinating questions: are there intelligent life forms out there somewhere in the cosmos and can they save us from ourselves? As for the first question, it seems highly likely life exits elsewhere in the universe. But it may have evolved in quite a different fashion under different evolutionary forces. Therefore, it may not be even perceivable by humans. We humans exist in four dimensions as far as we know. But some physicists are now suggesting there are more dimensions than just four. If so, our technology and capacity to communicate may be quite limited when it comes to having knowledge of life forms elsewhere.
Our human combination of manual dexterity and complex forebrain has resulted in the capacity for both creative and destructive technology. That technology has lent itself to the creation of transcendent beauty and unimaginable suffering and loss. It remains to be seen whether or not the web of life as we know it on this planet can survive we humans. But Life will certainly survive us
Your post reminds me of the Drake equation, which says the probability of intelligent life on a planet is a composite of factors including:
R* = The rate of formation of stars suitable for the development of intelligent life.
fp = The fraction of those stars with planetary systems.
ne = The # of planets with an environment suitable for life.
fl = The fraction of suitable planets on which life actually appears.
fi = The fraction of life bearing planets on which intelligent life emerges.
L = The length of time such civilizations persist in time before going extinct
R*, fp and ne seem encouragingly high, according to the data so far. Determining fl may be within reach in our galaxy’s neighborhood by detecting high amounts of water vapor and oxygen with future telescopes with high enough sensitivity. I suspect that fl mandates evolution of some kind, and therefore with enough time, evolution of intelligent life, given the biological advantages conferred by intelligence.
The last criterion, L, is less encouraging based on the one planet we know — our own. L would seem to depend on whether the intelligent life form evolves the capability to make tools, control fire, and eventually control the environment on a large scale. Presumably, with sufficient time, even cetaceans and elephants may evolve this capability, given its evolutionary advantages. So, I would surmise that given fi and evolution, the ability to seriously degrade the environment to the point of extinction is inevitable. The big question for me, then, is whether a tool-making intelligent species can co-exist with the unintended consequences of their own intelligence over long time scales. This could be further analyzed by an extension of the Drake equation, where L is a function of:
Ts = probability the species figures out how to manage its cravings and its technologies to sustain the ecosystems and resources (land, sea, air) the species depends on;
Tai = probability the species doesn’t lose the competition for survival with the AI systems, robots and other technologies it createsl;
Tp = probability the species doesn’t lose the competition for survival with the pathogens it genetically modifies for survival;
Tt = the probability the species doesn’t lose the competition for survival with other aliens or phenomena we can’t think of yet.
Based on what I’ve observed about my own species on planet earth, if our species is fairly typical of others at this stage of development, the probabilities for coexisting sustainably with ourselves will start out low (reflecting a primitive level of development) but could improve with time. They are all a function of culture. The key cultural variables include (imho): 1) ability of the culture to evolve for species-wide cooperation over tribalism/nationalism; 2) ability of the culture to discern probable truth from probable falsehood, particularly about the species’ shortcomings and biases (possibly with the help of AI), and correct for these; 3) ability of the culture and species to form institutions for planet-wide self-regulation (possibly with the help of AI).
In short, a species doesn’t necessarily have to depend entirely on its biologically limited intelligence to solve the problems it creates if a widely recognized superior intelligence (“oracle”) in the form of AI exists to help. This too would require advanced AI systems and high levels of development (e.g. education) for the extreme cooperation required.