TheSkySearchers

https://phys.org/news/2021-11-alien-pro ... -home.html

There's a bit of specious reasoning:

According to accepted models, the Milky Way galaxy formed roughly 13.51 billion years ago, followed by the first planets 500 million years later. Our solar system is a relative newcomer, having formed 4.5 billion years ago, and humanity has only existed for the last 200,000 years. It stands to reason that intelligent species have already emerged and have had the necessary time to colonize the Milky Way.

This is like a Drake equation (ack! pooh!) argument that is mere numerology. The dynamics could well have us as the 1st or 2nd technological civilization in the MW.

The Fermi Paradox shows the reasoning specious.

I would argue that there is a partial solution to the first five or six steps of the Drake equation - right up to 'number of stars with appropriately sized planets in their habitable zones,' but past that, 'numerology' about sums it up...at least until better data becomes available. Then, it might be feasible to make a realistic rough calculation as to the total number of 'other Earths' in the galaxy. Past that, though, still numerology.

Maybe it helps to find out how many ways life on Earth could have failed to exist? :wink:

turboscrew wrote: ↑Tue Nov 23, 2021 9:04 pm Maybe it helps to find out how many ways life on Earth could have failed to exist? :wink:

Exactly so! For instance a large Moon and tides may be necessary. That cuts the odds substantially.

Eukaryotes have only arisen once on Earth, roughly 2 billion years ago, and it seems to have been a lucky accident. Without that there would still only be bacteria on Earth. Nobody knows how likely it was to happen, so it might have been a one in a thousand or one in a million chance. If so then civilisations must be very rare indeed. It is impossible to calculate.

Being the technologically primitive species that we are, I really doubt that any alien from any other star system would be using the crude communications we utilize. Comparatively, would be like thinking that looking for smoke signals would be useful

WilliamPaolini wrote: ↑Wed Nov 24, 2021 2:05 am Being the technologically primitive species that we are, I really doubt that any alien from any other star system would be using the crude communications we utilize. Comparatively, would be like thinking that looking for smoke signals would be useful

There's that speed of light problem though..... "Subspace communications" make sci fi entertaining but.... speed of light.

notFritzArgelander wrote: ↑Tue Nov 23, 2021 9:06 pm

turboscrew wrote: ↑Tue Nov 23, 2021 9:04 pm Maybe it helps to find out how many ways life on Earth could have failed to exist? :wink:

Exactly so! For instance a large Moon and tides may be necessary. That cuts the odds substantially.

And the Theia Hypothesis reduces those odds to near insignificance.
I haven't seen anybody (reputable) make the suggestion yet, but Theia may also have been necessary for this world's potential for life. That's actually an extremely long chain of conjectures to string together, but the Theia Hypothesis is gaining ground every year. As its implications for the origin of Earth are better understood, it may someday be possible to connect that event to the favourable conditions for life on Earth's early surface.

SparWeb wrote: ↑Wed Nov 24, 2021 5:17 am

notFritzArgelander wrote: ↑Tue Nov 23, 2021 9:06 pm

turboscrew wrote: ↑Tue Nov 23, 2021 9:04 pm Maybe it helps to find out how many ways life on Earth could have failed to exist? :wink:

Exactly so! For instance a large Moon and tides may be necessary. That cuts the odds substantially.

And the Theia Hypothesis reduces those odds to near insignificance.
I haven't seen anybody (reputable) make the suggestion yet, but Theia may also have been necessary for this world's potential for life. That's actually an extremely long chain of conjectures to string together, but the Theia Hypothesis is gaining ground every year. As its implications for the origin of Earth are better understood, it may someday be possible to connect that event to the favourable conditions for life on Earth's early surface.

I think I’ve posted before on reputable folks discussing the necessity of a large moon, from Theia, as a necessary step. Let me see if I can dig up a refresher.

WilliamPaolini wrote: ↑Wed Nov 24, 2021 2:05 am Being the technologically primitive species that we are,...

Umm, compared to...?

turboscrew wrote: ↑Wed Nov 24, 2021 3:37 pm

WilliamPaolini wrote: ↑Wed Nov 24, 2021 2:05 am Being the technologically primitive species that we are,...

Umm, compared to...?

The unfounded optimism that there are no limits to scientific and technological advances.

The advances in science at a fundamental level are coming more slowly, more expensively. Any future science must be compatible with all experiments and observations satisfied by current theory. That is why "unfounded optimism".

notFritzArgelander wrote: ↑Wed Nov 24, 2021 3:58 pm

turboscrew wrote: ↑Wed Nov 24, 2021 3:37 pm

WilliamPaolini wrote: ↑Wed Nov 24, 2021 2:05 am Being the technologically primitive species that we are,...

Umm, compared to...?

The unfounded optimism that there are no limits to scientific and technological advances.

The advances in science at a fundamental level are coming more slowly, more expensively. Any future science must be compatible with all experiments and observations satisfied by current theory. That is why "unfounded optimism".

And any technology can't get past limitations of physics.
If we haven't found any signals faster than light, no technology can make us travel faster than light.

turboscrew wrote: ↑Wed Nov 24, 2021 3:37 pm

WilliamPaolini wrote: ↑Wed Nov 24, 2021 2:05 am Being the technologically primitive species that we are,...

Umm, compared to...?

Why compared to the fictitious aliens that this post is positing that may have probes in our solar system. If one is going to assume there is an alien, then one also must make an assumption as to their technological capability as well. In my response I am making the inference that the original post is stating that these supposed aliens could be, if not likely, from another solar system. Given that premise, technologically humans are no where near being able to practically accomplish such a feat (except in our imaginations at present). Therefore, we would be technologically primitive in comparison.

And observing our own example, if in 1721 someone went about bringing all of human technology to bear to detect if there were people from other worlds, you know full well that they would not have tried to detect, or even envisioned, radio signals. Of course, hundreds of years later that is in the realm of possibility for current day humans. So point being, you only know what you know, and to assume that you know all there is to know is of course great folly (and extreme hubris), as history teaches us. So with that, it is a fairly low risk assumption that in the posit that there may be aliens in our solar system from outside our solar system, since they would be doing what we at present cannot, some of their technology as well would be outside our knowledge and understanding, and therefore we would not be able to detect it given we have no idea what to look for. And given our current understanding on the age of the universe and the progression of life at least here on Earth, if life has arisen elsewhere then well within the realm of possibility that it could be not just hundreds, but thousands or millions of years more advanced than we are, meaning that what we use and look for would be akin to stone tools.

Now, if the original question framed it as aliens of the same relative technological advancement as humans, then that would be a different story. But if it did frame it that way then since we cannot readily probe other solar systems from within those systems using technologies we have sent there, then neither would they, unless the aliens framed as being similar to us technologically were from our own solar system sending probes to the other planets -- unlikely or we would have seen. So the only reasonable framing of the question posed IMO is with the assumption that the aliens are not from this solar system, and therefore would be more advanced than we are definitely in engineering to accomplish that feat, and most likely technologically as well.

WilliamPaolini wrote: ↑Wed Nov 24, 2021 4:31 pm

turboscrew wrote: ↑Wed Nov 24, 2021 3:37 pm

WilliamPaolini wrote: ↑Wed Nov 24, 2021 2:05 am Being the technologically primitive species that we are,...

Umm, compared to...?

Why compared to the fictitious aliens that this post is positing that may have probes in our solar system. If one is going to assume there is an alien, then one also must make an assumption as to their technological capability as well. In my response I am making the inference that the original post is stating that these supposed aliens could be, if not likely, from another solar system. Given that premise, technologically humans are no where near being able to practically accomplish such a feat (except in our imaginations at present). Therefore, we would be technologically primitive in comparison.

Incorrect. The construction of von Neumann machine probes is within a few decades. So any hypothetical aliens need only be just a little ahead of us.

And observing our own example, if in 1721 someone went about bringing all of human technology to bear to detect if there were people from other worlds, you know full well that they would not have tried to detect, or even envisioned, radio signals. Of course, hundreds of years later that is in the realm of possibility for current day humans. So point being, you only know what you know, and to assume that you know all there is to know is of course great folly, as history teaches us. So with that, it is a fairly low risk assumption that in the posit that there may be aliens in our solar system from outside our solar system, since they would be doing what we at present cannot, some of their technology as well would be outside our knowledge and understanding, and therefore we would not be able to detect it given we have no idea what to look for. And given our current understanding on the age of the universe and the progression of life at least here on Earth, if life has arisen elsewhere then well within the realm of possibility that it could be not just hundreds, but thousands or millions of years more advanced than we are, meaning that what we use and look for would be akin to stone tools.

This is Drake equation nonsense that is based on numerology not physics. We could well be the first technological civilization in the Galaxy.

https://academic.oup.com/mnras/article/ ... 11/1046202
https://www.npr.org/sections/13.7/2016/ ... e-universe

Now, if the original question framed it as aliens of the same relative technological advancement as humans, then that would be a different story. But if it did frame it that way then since we cannot readily probe other solar systems from within those systems using technologies we have sent there, then neither would they, unless the aliens framed as being similar to us technologically were from our own solar system sending probes to the other planets -- unlikely or we would have seen. So the only reasonable framing of the question posed IMO is with the assumption that the aliens are not from this solar system, and therefore would be more advanced than we are definitely in engineering to accomplish that feat, and most likely technologically as well.

Since the premises are arguably flawed the proposed conclusion cannot be drawn.

I think we are the only civilization this far - we earthlings - that we have observed.
And statistics based on only one observation has infinite error range.
I mean, we could be the most advanced civilization in the universe - or least advanced.
Even both at the same time.
I guess it's pointless trying to figure out the probability of other existing civilizations, when we really don't have a clue of our own failure probabilities that we have beaten.
I mean, now the probability of our existence is 1, but if life was suddenly wiped out from the Earth, what's the probability life returns back on Earth? Do we have even rough estimate of that?

turboscrew wrote: ↑Wed Nov 24, 2021 7:34 pm I think we are the only civilization this far - we earthlings - that we have observed.
And statistics based on only one observation has infinite error range.
I mean, we could be the most advanced civilization in the universe - or least advanced.
Even both at the same time.
I guess it's pointless trying to figure out the probability of other existing civilizations, when we really don't have a clue of our own failure probabilities that we have beaten.
I mean, now the probability of our existence is 1, but if life was suddenly wiped out from the Earth, what's the probability life returns back on Earth? Do we have even rough estimate of that?

This is a rational argument if you base it on frequentist statistics.

However with a Bayesian approach it is possible to model the likelihood of life prior to its appearance and then use the fact that we have observed 1 technological civilization to constrain the infinite range of possible prior likelihood models.

The fact that we have observed only 1 such and the Fermi paradox argue that basing priors on Drake equation style arguments gives an unrealistic overestimation of the prior probabilities.

Given our history and prospects there are serious doubts about whether we will last long enough to launch the von Neumann probes that could populate the Galaxy in a few revolution times.

Another thing: I don't thing there exists "unkown to us" physics that would let any "space creatures" to communicate with someone in some other galaxy, or even some other star system in reasonable time. What would some other civilization do with, say, 1000 years old information?

turboscrew wrote: ↑Wed Nov 24, 2021 7:52 pm Another thing: I don't thing there exists "unkown to us" physics that would let any "space creatures" to communicate with someone in some other galaxy, or even some other star system in reasonable time. What would some other civilization do with, say, 1000 years old information?

Any physics that is unknown to us MUST be compatible with the physics that is known to us. The history of physics can be best read IMO as increasingly limiting what is possible. At the time of Newton any speed was possible. Relativity imposed a speed limit. At the time of Newton any minute action was possible. QM imposed a limit below, a minimum amount of action.

Another civilization could only update their ancient history with 1000 year old information.

notFritzArgelander wrote: ↑Wed Nov 24, 2021 7:58 pm

turboscrew wrote: ↑Wed Nov 24, 2021 7:52 pm Another thing: I don't thing there exists "unkown to us" physics that would let any "space creatures" to communicate with someone in some other galaxy, or even some other star system in reasonable time. What would some other civilization do with, say, 1000 years old information?

Any physics that is unknown to us MUST be compatible with the physics that is known to us. The history of physics can be best read IMO as increasingly limiting what is possible. At the time of Newton any speed was possible. Relativity imposed a speed limit. At the time of Newton any minute action was possible. QM imposed a limit below, a minimum amount of action.

Another civilization could only update their ancient history with 1000 year old information.

Not quite. Discovering electricity broadened the possibilities. :smile:
But these days, I think such basic forces are found. And even if we don't really know what dark matter or dark energy are, I think we know enough to tell, they are not something that could be used for faster-than-light communication or transportation.

turboscrew wrote: ↑Wed Nov 24, 2021 8:59 pm

notFritzArgelander wrote: ↑Wed Nov 24, 2021 7:58 pm

turboscrew wrote: ↑Wed Nov 24, 2021 7:52 pm Another thing: I don't thing there exists "unkown to us" physics that would let any "space creatures" to communicate with someone in some other galaxy, or even some other star system in reasonable time. What would some other civilization do with, say, 1000 years old information?

Any physics that is unknown to us MUST be compatible with the physics that is known to us. The history of physics can be best read IMO as increasingly limiting what is possible. At the time of Newton any speed was possible. Relativity imposed a speed limit. At the time of Newton any minute action was possible. QM imposed a limit below, a minimum amount of action.

Another civilization could only update their ancient history with 1000 year old information.

Not quite. Discovering electricity broadened the possibilities. :smile:

I'll defend by pointing out that Maxwell's equations contain that nasty speech of light limit.

But these days, I think such basic forces are found. And even if we don't really know what dark matter or dark energy are, I think we know enough to tell, they are not something that could be used for faster-than-light communication or transportation.

Exactly so.