We are effectively alone in the universe

[C C]

https://bigthink.com/surprising-science/...e-universe

KEY POINTS: The debate over extraterrestrial life has shifted from fringe to mainstream. The belief that humans eventually will encounter aliens is based on two assumptions: (a) life evolves easily, and (b) interstellar travel is possible and practical. Neither of these assumptions is likely to be true.

EXCERPTS (Alex Berezow): When I was a kid ... outside of popular culture, few serious intellectuals took the notion of aliens seriously. ... Today, the exact opposite view prevails.

Thanks to advances ... most of the scientific community [...concludes...] that life probably does exist elsewhere in the universe. Those who do not believe so are now considered the kooks. And while alien abductions are still not in the mainstream, UFOs are — so much so that the U.S. intelligence community just issued a report on them.

The academic debate now is not whether life exists but in what form. [...] I suppose this is all fun to think and talk about, but the alien debate suffers from a serious lack of perspective. If there is any chance of humans encountering alien life, at least two extremely unlikely things must be true:

Life evolves easily. Decades of research have yielded little in the way of identifying the mechanism of abiogenesis — the formation of life from non-living matter. [...] In the laboratory ... scientists have yet to come even close to reproducing life in the laboratory. This strongly implies that life does not evolve easily. But even if we were to cede the point that life can evolve easily given enough time, there is another problem: the vast majority of exoplanets are inhospitable to life...

Interstellar travel is possible and practical. This, in my opinion, is even more unlikely than the easy evolution of life. [...] we have no idea if interstellar travel is possible. Sure, we could get on a spaceship today and head for a planet orbiting the nearest star, Proxima Centauri ... it will take about 6,300 years to get there.

The notion that we will develop (or that some advanced alien civilization has already developed) the ability to easily traverse the galaxy is pure speculation. It is physically impossible to travel at the speed of light, though it may be possible to travel at a substantial fraction of the speed of light. [...] the distances between stars is nearly unfathomable ... Sci-fi enthusiasts note that unknown technologies may develop ... But again, these suggestions are purely speculative.

Putting all this together, the sobering conclusion is that it does not matter if intelligent alien life exists elsewhere in the universe. We will never find them, and they will never find us. In other words, we are effectively alone in the universe... (MORE - missing details)

[Zinjanthropos]

Life could still evolve easily, intelligence not so much. The only reason we may have it is because our species was too weak physically to survive. Intelligence was a freak of nature/evolution. An adaptation that may have been lucky enough, by the slimmest of margins, to actually take hold.

Even if we are alone, there’s no timetable that I know of that schedules the arrival of intelligent beings. For all we know, we could be the first. 15-18 bn yrs to get to this point could be the gestation period for intelligence in this universe.. There’s a long way to go..

Why do we assume any or all intelligences would look to conquer interstellar space?

[C C]

[...] Why do we assume any or all intelligences would look to conquer interstellar space?

They project our level of curiosity and adventuresomeness upon them.

Maybe they assume _X_ is as unable to control its reproduction and consumption rate as humans (i.e., runaway status) and can no longer be kept in check by the regulating aspects of its environment -- eventually runs into resource problems even after colonization of its solar system and several million years. Ignoring any possibility of being replaced by artificial descendants with an inherent penchant for limits.

That cultural evolution ultimately leads to democratic institutions and personal freedoms rather than an authoritarian condition that can force the population to do what it needs to do to survive under limited environmental constraints. Or, alternative to the latter -- is like an ant colony, where the class and function and social conduct of the individual are innate to it (which could be even more runaway and entail an impetus to spread beyond the place of origin).

Just all manner of anthropocentric and terrestrial-centric attributes, including having a progressive technology. List of motivated or unwarranted presumptions slash expectations is endless.

[Yazata]

EXCERPTS (Alex Berezow): When I was a kid ... outside of popular culture, few serious intellectuals took the notion of aliens seriously. ... Today, the exact opposite view prevails.

Thanks to advances ... most of the scientific community [...concludes...] that life probably does exist elsewhere in the universe. Those who do not believe so are now considered the kooks.

I get the feeling that Dr. Berezow is confusing two different ideas

1. The idea that life (ex hypothesi intelligent life) exists elsewhere in the universe. 

2. The idea that humans will someday meet hypothetical intelligent alien life, or even that intelligent alien life is visiting Earth today.

These are two very different propositions. While I personally think that the likelihood of 1. is high, I simultaneously think that the likelihood of 2. is low.

And while alien abductions are still not in the mainstream, UFOs are — so much so that the U.S. intelligence community just issued a report on them.

Of course one shouldn't covertly introduce the implicit premise that UFOs are somehow equivalent to space aliens. All that the US intelligence community said was that it looks to them like real flying objects are out there that they can't currently account for.

The academic debate now is not whether life exists but in what form.

Yes. It goes direct to the heart of the philosophy of biology, a subject dear to my heart. What is life? What minimum set of characteristics must a physical system have to be called 'alive'? How can space explorers even recognize alien life if they encounter it? How universal must Earth-style cells, genetic codes, nucleic acids like dna, and all the rest, be out there? How many other ways exist to accomplish things that are similar in a functional sense?

I suppose this is all fun to think and talk about, but the alien debate suffers from a serious lack of perspective. If there is any chance of humans encountering alien life, at least two extremely unlikely things must be true:

I should repeat that the chances of humans encountering alien life have little or no bearing on the likelihood of alien life existing out there in the wider universe. It's not like it can't exist unless we encounter it.

Life evolves easily. Decades of research have yielded little in the way of identifying the mechanism of abiogenesis — the formation of life from non-living matter. [...] In the laboratory ... scientists have yet to come even close to reproducing life in the laboratory. This strongly implies that life does not evolve easily. But even if we were to cede the point that life can evolve easily given enough time, there is another problem: the vast majority of exoplanets are inhospitable to life...

We just don't know how easy it is for "life" (however we define it) to appear. I think that I would agree with Dr. Berezow that life isn't something that inevitably appears whenever conditions are suitable (whatever that means). I'm inclined to think that it's probably far more fortuitous than that, the result of a whole succession of lucky events.

Regarding whether exoplanets are hospitable to life, we probably need to keep in mind that life evolves to fit its environment, not the other way around. Just because conditions would be deadly for Earth life doesn't mean that there can't be beings with substantially different chemistries that just love swimming in seas of liquid methane and are wonderfully adapted to it.

And we need to keep in mind that at the present time we possess only a tiny sampling of exoplanets, particularly massive ones very close to their stars able to move those stars in ways detectable by doppler. So our sample is not only infinitesimally small, it's heavily biased.

Interstellar travel is possible and practical. This, in my opinion, is even more unlikely than the easy evolution of life. [...] we have no idea if interstellar travel is possible. Sure, we could get on a spaceship today and head for a planet orbiting the nearest star, Proxima Centauri ... it will take about 6,300 years to get there.

The notion that we will develop (or that some advanced alien civilization has already developed) the ability to easily traverse the galaxy is pure speculation. It is physically impossible to travel at the speed of light, though it may be possible to travel at a substantial fraction of the speed of light. [...] the distances between stars is nearly unfathomable ... Sci-fi enthusiasts note that unknown technologies may develop ... But again, these suggestions are purely speculative.

Well sure it's speculative. But that isn't really the same thing as an argument that it's impossible. And again, the likelihood of aliens visiting us or us visiting them really has nothing to do with the likelihood of intelligent life existing out there in the wider universe.

Putting all this together, the sobering conclusion is that it does not matter if intelligent alien life exists elsewhere in the universe. We will never find them, and they will never find us. In other words, we are effectively alone in the universe...

The existence of intelligent alien life only "matters" if we can someday meet face to face?

I think that if we accept the implicit premise there, then Dr. Berezow might arguably be right. If "life" (however we define it) is very thinly distributed through the universe and intelligent life with technological cultures is even more rare. And if interstellar travel will remain exceedingly difficult for beings at all levels of technology.

Except that we don't really know whether either of those is true. It seems plausible to think so, but that's all it is. An exercise in speculation.

[Syne]

I get the feeling that Dr. Berezow is confusing two different ideas

1. The idea that life (ex hypothesi intelligent life) exists elsewhere in the universe. 

2. The idea that humans will someday meet hypothetical intelligent alien life, or even that intelligent alien life is visiting Earth today.

These are two very different propositions. While I personally think that the likelihood of 1. is high, I simultaneously think that the likelihood of 2. is low.

Your statement (emphasized) seems to be exactly what he's saying, just without your unsupported assumption of 1 being likely.

Well sure it's speculative. But that isn't really the same thing as an argument that it's impossible.

All of our current science says it's definitively not possible. Aside from uninformed sci-fi, we can't even fathom a physics that would allow it in reality.

The existence of intelligent alien life only "matters" if we can someday meet face to face?

Not meet, but certainly it only makes a difference if we could even know it's out there. He said "find", not "meet."

[C C]

[...] The existence of intelligent alien life only "matters" if we can someday meet face to face?

I think that if we accept the implicit premise there, then Dr. Berezow might arguably be right. If "life" (however we define it) is very thinly distributed through the universe and intelligent life with technological cultures is even more rare. And if interstellar travel will remain exceedingly difficult for beings at all levels of technology.

Except that we don't really know whether either of those is true. It seems plausible to think so, but that's all it is. An exercise in speculation.

Maybe a member of a particular class of speculations: Does the verification of talking unicorns matter?

Certainly, it matters to a unicorn that it exists.

But from the standpoint of humans, it's only the idea of unicorns that makes an impact in commercial creativity.

Barring actually verifying one. Which might or might not change human culture and perspective in a radical way.

But unlikely to happen if, say, unicorns exist in the distant future or a parallel universe or a situation that might as well be rubbing against similar barriers.

[Zinjanthropos]

For the most part, including myself, I think we associate intelligent beings as creatures who exist in a non liquid environment. On dry land if you wish. Wouldn’t surprise me that since life is thought to have begun in water that most life in the universe exists in a watery/liquid environment. Could an intelligent species evolve beneath the waves and would they be able to advance technologically speaking? Can’t see underwater intelligences developing same sort of technology as those in a drier zone. Might make what happened here a genuine rarity.

[Syne]

Whereas chimps and crows are known to use tools, which is likely a prerequisite to any kind of technology or further advancement, I'm not aware of any underwater creatures that do.

[Magical Realist]

''A female bottlenose dolphin (Tursiops sp. ) carries a sponge, which it uses as a tool to dig up prey from the seafloor. The only dolphins known to use sponges as tools this way are the female members of a small group that live in Shark Bay, Australia. They pass the skill onto their daughters, but not their sons."--- https://ocean.si.edu/ocean-life/marine-m...eir%20sons.

[Syne]

''A female bottlenose dolphin (Tursiops sp. ) carries a sponge, which it uses as a tool to dig up prey from the seafloor. The only dolphins known to use sponges as tools this way are the female members of a small group that live in Shark Bay, Australia. They pass the skill onto their daughters, but not their sons."--- https://ocean.si.edu/ocean-life/marine-m...eir%20sons.

The sponge is not used as a tool for digging, it's used to protect their snout: https://www.youtube.com/watch?v=-zdzROgOELM
The same as hermit crabs seeking out a shell for protection.