Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Updated Drake Equation

  • Please log in to reply
97 replies to this topic

#1 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 19,119
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 28 October 2019 - 09:52 PM

Just came across this paper from 2018 by Oxford University and funded through the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program.  Curious what others think about this updated approach!

 

https://arxiv.org/pdf/1806.02404.pdf

 

Cutting to the conclusion, here's their take --

 

"We have seen that a Fermi paradox arises if we combine a high and extremely confident prior for the number of civilizations in our galaxy with the absence of evidence for their existence. The high confidence that causes this clash typically results from applying a Drake-like model using point estimates for the parameters. These estimates, however, make implicit knowledge claims about processes (especially those connected with the origin of life) which are untenable given the current state of scientific knowledge.When we take account of realistic uncertainty, replacing point estimates by probability distributions that reflect current scientific understanding, we find no reason to be highly confident that the galaxy (or observable universe) contains other civilizations, and thus no longer find our observations in conflict with our prior probabilities. We found qualitatively similar results through two different methods: using the authors’ assessments of current scientific knowledge bearing on key parameters, and using the divergent estimates of these parameters in the astrobiology literature as a proxy for current scientific uncertainty.When we update this prior in light of the Fermi observation, we find a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). ’Where are they?’— probably extremely far away, and quite possibly beyond the cosmological horizon and forever unreachable."

 

PS - Please resist the urge to introduce theological considerations into this thread since that is outside the scope of and irrelevant to the Drake Equation and this updated Drake Equation.  It would be nice to get other's take on what they think of this new approach to the Drake Equation rather than having the thread get locked due to some not respecting our CN community's TOS for discussions flowerred.gif


Edited by BillP, 28 October 2019 - 09:59 PM.

  • DHEB likes this

#2 Sleep Deprived

Sleep Deprived

    Mariner 2

  • *****
  • Posts: 211
  • Joined: 17 Apr 2019
  • Loc: Seattle Area

Posted 28 October 2019 - 10:54 PM

My take on the Drake Equation is that it is probably pretty good for what it is - a first-generation attempt at determining whether we are alone or not.  As our understanding of the Universe increases, I suspect the Drake Equation will evolve - new factors or even splitting existing factors into smaller 'bites', especially when/if we have a quantum leap in understanding of a particular 'bite'.  All in all, though, so many of the factors have widely (wildly?) varying values (read: guesses) and altogether I suspect the range of possible civilizations ranges from none at all in the galaxy to dozens/hundreds/thousands.  We don't even know the likelihood of life in a watery environment.  I am reading in the astronomy press about how we should be going to Mars, Enceledus, Triton, Titan, Europa, Ganymede, and a few others where liquid water is conjectured.  Almost like if we find liquid water, we could almost expect to find life.  I am sure part of this bias is to pump up interest/sales.  But THERE IS A BIAS.  Having said that, I do think we need to go to these places to see (1) if there is/was liquid water, and (2) if there is/was life.  After we do that, we can get a better understanding of some of the Drake Equation factors.  In the Solar System, I suspect we WILL find water, and that we WILL NOT find life, but that is yet to be seen.  Anyway, scientific dogma says we should follow the evidence, and aside from some mathematical equations indicating a possibility (or even probability) of intelligent life, we have no evidence.  A single example is, at best, ANECDOTAL evidence.  It says that life CAN form, but it doesn't indicate what the probability is that it will more than once

 

I suspect intelligent life is profoundly rare.  We haven't heard a peep from anyone, anywhere.  I HOPE we find nearby life - the idea of that is really intriguing - but the EVIDENCE says it's not likely.  Of course, 'not likely' could flip to 'likely' (or even 'confirmed') overnight, but until that paradigm-shifting evidence is found, in my mind, it is unlikely.  Belongs in the realm of science fiction.  We should keep looking, though.  And get some very stubborn people on the search.  Can you imagine spending your entire career looking for something that never happens?  Not me.  And, of course, we'll never prove that intelligent life DOESN'T exist out there --- we may go for millennia with no results.  At what point do you say, "I guess there's nothing out there"??

 

I see the Drake Equation as almost an interesting mathematical exercise in combining wildly large and small factors in order to get a single comprehensible result.  It is good for what it is, but really, what is it?


  • deepwoods1 likes this

#3 pkrallis

pkrallis

    Mariner 2

  • *****
  • Posts: 244
  • Joined: 06 Oct 2007
  • Loc: Colorado Springs, CO

Posted 28 October 2019 - 11:03 PM

I have a feeling that we ae being prepared for the revelation of ETs existence in the very near future making the equation moot.  But then I'm gnostic, believe in reincarnation, and other things that people think weird.  


  • ghostboo and Dynan like this

#4 rekokich

rekokich

    Viking 1

  • *****
  • Posts: 856
  • Joined: 14 Sep 2014
  • Loc: Virginia

Posted 29 October 2019 - 12:54 AM

Bill,

 

Here is an article which precisely addresses your issue:

https://www.cloudyni...i-paradox-r3162

 

I do not think it is scientifically valid to apply ANY statistical method to a problem for which there is only ONE point of data. The Monte Carlo simulation model is then just as imprecise as the Drake model. Until we collect a great deal more information on the Solar system and exoplanets, the only reliable statements we can make are that life is possible, intelligence is possible and, over time, life can evolve from less to more complex forms.

 

Everything else is speculation, where the results of the selected statistical model depend on the balance of optimism and pessimism of the speculator.

 

My personal opinion is that we should not prejudice any investigation with excessive self-regard by assuming that Earth, terrestrial life, or human intelligence are unique in the entire universe.


  • llanitedave, Jeff Lee, Miguelo and 4 others like this

#5 DaveC2042

DaveC2042

    Mariner 2

  • -----
  • Posts: 224
  • Joined: 18 Jul 2018
  • Loc: Sydney, Australia

Posted 29 October 2019 - 02:05 AM

My take on the Drake Equation is that it is probably pretty good for what it is - a first-generation attempt at determining whether we are alone or not.  As our understanding of the Universe increases, I suspect the Drake Equation will evolve - new factors or even splitting existing factors into smaller 'bites', especially when/if we have a quantum leap in understanding of a particular 'bite'.  All in all, though, so many of the factors have widely (wildly?) varying values (read: guesses) and altogether I suspect the range of possible civilizations ranges from none at all in the galaxy to dozens/hundreds/thousands.  We don't even know the likelihood of life in a watery environment.  I am reading in the astronomy press about how we should be going to Mars, Enceledus, Triton, Titan, Europa, Ganymede, and a few others where liquid water is conjectured.  Almost like if we find liquid water, we could almost expect to find life.  I am sure part of this bias is to pump up interest/sales.  But THERE IS A BIAS.  Having said that, I do think we need to go to these places to see (1) if there is/was liquid water, and (2) if there is/was life.  After we do that, we can get a better understanding of some of the Drake Equation factors.  In the Solar System, I suspect we WILL find water, and that we WILL NOT find life, but that is yet to be seen.  Anyway, scientific dogma says we should follow the evidence, and aside from some mathematical equations indicating a possibility (or even probability) of intelligent life, we have no evidence.  A single example is, at best, ANECDOTAL evidence.  It says that life CAN form, but it doesn't indicate what the probability is that it will more than once

 

I suspect intelligent life is profoundly rare.  We haven't heard a peep from anyone, anywhere.  I HOPE we find nearby life - the idea of that is really intriguing - but the EVIDENCE says it's not likely.  Of course, 'not likely' could flip to 'likely' (or even 'confirmed') overnight, but until that paradigm-shifting evidence is found, in my mind, it is unlikely.  Belongs in the realm of science fiction.  We should keep looking, though.  And get some very stubborn people on the search.  Can you imagine spending your entire career looking for something that never happens?  Not me.  And, of course, we'll never prove that intelligent life DOESN'T exist out there --- we may go for millennia with no results.  At what point do you say, "I guess there's nothing out there"??

 

I see the Drake Equation as almost an interesting mathematical exercise in combining wildly large and small factors in order to get a single comprehensible result.  It is good for what it is, but really, what is it?

I think the nice thing about the Drake Equation given its relevance to the Fermi Paradox, is that it is a Fermi Estimate.

 

https://en.wikipedia...i/Fermi_problem

 

In reality most of the terms are so open there isn't a whole lot of point trying to use it as a way of estimating the actual rate life.  It's better thought of as just framework for understanding the problem.



#6 Sleep Deprived

Sleep Deprived

    Mariner 2

  • *****
  • Posts: 211
  • Joined: 17 Apr 2019
  • Loc: Seattle Area

Posted 29 October 2019 - 02:13 AM

I agree with your post rekokich.  Although I cannot prove it, I suspect if we come up with our 'best guess' of a series of factors (or 'arbitrarily' take the centerpoint of a series of ranges) that we end up with skewed results.  I suspect for something that is basically rare, that this method over-estimates reality, and if something is common, that it under-estimates reality.  I also suspect it over-emphasizes bias inherent to the people coming up with those numbers.  For instance, if we theorize that a certain class of star could harbor life, but for some reason that certain class of star is preferentially more common near the active center of a galaxy, there may be a bunch of those stars, but because of their location none of them would have life.  Or, perhaps the number of exoplanets around the correct class of star is preferentially metal-poor for some reason.  Anyway, for something inherently scarce (like intelligent life in the Universe), I would bet all of these effects cause the final # of civilizations to go DOWN compared to the calculated #.  The interplay between Factor1, Factor2, Factor3, etc, may have a major effect on the final calculation above and beyond the basic values of each of those factors.

 

In the end, if we are ever able to pin down the values for the various factors in the Drake Equation, we will find intelligent life to be rarer than that.  I suspect there is (at least, but I will only name one) a missing factor, which could simply be called the "Fudge Factor" which factors in the inter-relationships between the list of factors.  Just my 2-cents worth.


Edited by Sleep Deprived, 29 October 2019 - 02:14 AM.


#7 Sleep Deprived

Sleep Deprived

    Mariner 2

  • *****
  • Posts: 211
  • Joined: 17 Apr 2019
  • Loc: Seattle Area

Posted 29 October 2019 - 02:29 AM

 

In reality most of the terms are so open there isn't a whole lot of point trying to use it as a way of estimating the actual rate life.  It's better thought of as just framework for understanding the problem.

 

Thank you, DaveC.  I was going to say that if the Drake Equation is anything useful at all, it is a 'map' to guide us in our scientific search and to help us 'mold' a paradigm for our understanding of what it takes for intelligent life to occur.  There are lots of scientists studying things that have a direct bearing on so many of the 'factors'.  Although some may be driven by the desire to 'fill in the blanks' (of the Drake Equation) I suspect most are driven by other forces, just as most scientists are studying fields unrelated to the Drake Equation at all.  There are enough scientists and enough varied needs/interests of those scientists that progress in the fields associated with the 'factors' probably happens organically.  Someone with the Drake Equation in mind will someday take the results of these scientists and make a more informed argument for (or against, I suppose) the frequency of intelligent life in the universe.



#8 Ring_Singularity

Ring_Singularity

    Messenger

  • ****-
  • Posts: 488
  • Joined: 27 Aug 2014

Posted 29 October 2019 - 07:31 AM

Actually being alone is good news, it means lots of potentially habitable worlds to colonize- a la the Asimovian vision of our galaxy!



#9 Ring_Singularity

Ring_Singularity

    Messenger

  • ****-
  • Posts: 488
  • Joined: 27 Aug 2014

Posted 29 October 2019 - 07:34 AM

Bill,

 

Here is an article which precisely addresses your issue:

https://www.cloudyni...i-paradox-r3162

 

I do not think it is scientifically valid to apply ANY statistical method to a problem for which there is only ONE point of data. The Monte Carlo simulation model is then just as imprecise as the Drake model. Until we collect a great deal more information on the Solar system and exoplanets, the only reliable statements we can make are that life is possible, intelligence is possible and, over time, life can evolve from less to more complex forms.

 

Everything else is speculation, where the results of the selected statistical model depend on the balance of optimism and pessimism of the speculator.

 

My personal opinion is that we should not prejudice any investigation with excessive self-regard by assuming that Earth, terrestrial life, or human intelligence are unique in the entire universe.

Not only that but perhaps they communicate in a way we wouldn't even recognize as communication.  On top of that they may be inorganic, even particles of dust that exist in interstellar space that travel together.  Intelligent life may exist in a form we may never recognize as such.


  • rekokich likes this

#10 Dynan

Dynan

    Soyuz

  • *****
  • Posts: 3,570
  • Joined: 11 Mar 2018
  • Loc: NOLA

Posted 29 October 2019 - 08:51 AM

Actually being alone is good news, it means lots of potentially habitable worlds to colonize- a la the Asimovian vision of our galaxy!

Most probably we will never get to any of these 'colonizable' planets. The distances are too vast. The technology needed will probably never materialize before we wipe the planet clean ecologically.

 

Even if a 'generational starship' launched, and lasted eons, Earth would never see or hear from them again. We'd never know the fate of space-born humanity.

 

Arthur C. Clarke's adage holds in this situation: "Don't commute. Communicate." So unless someone/something out there shoots out an intelligible signal, we're alone.


  • Miguelo likes this

#11 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 19,119
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 29 October 2019 - 09:15 AM

In reality most of the terms are so open there isn't a whole lot of point trying to use it as a way of estimating the actual rate life.  It's better thought of as just framework for understanding the problem.

 

I think that is absolutely spot on Dave waytogo.gif  Your contention is also echoed in the article I linked:

The Drake equation has been a mainstay in the SETI debate, sometimes being used to directly estimate the number of civilizations in the galaxy, but perhaps more often being used as an analysis tool. For example, it has played a prominent role in debating the rationality of SETI efforts.  This approach to the Drake equation is well summed up by Jill Tarter, who said ”The Drake Equation is a wonderful way to organize our ignorance”

 

I personally like the author's new approach to the Drake Equation.  Instead of focusing on what exact value a parameter might have, they looked at what the largest and smallest values each variable could have based on current knowledge.  Here's a great visual of the Drake Equation - https://www.sciencea...8-06/Drake1.jpg

 

A few years ago I added a great number of additional variables to the Drake Equation to bring it more up to date with what we know about the universe and its formation and what we've learned about biological development and success here on Earth, including the ongoing threats to the continuation or flourishing of human life here.  Basically flushing out the more detailed variables involved in each macro variable of the Drake Equation.  I also incorporated confidence intervals for each variable.  In the end my personal exercise yielded that was not likely that any more than 3 industrial civilizations exist in our galaxy at any overlapping point of time.  So pretty slim pickings and given the distances involved unlikely we would ever discover each other.  But in the end, adding so many variables to the equation did more of what you said than anything else, really expanded the framework for understanding the scope of the problem.  So very much has to go just right it seems to allow life sufficient time to get to a point of intelligence and industrialization.  And once there, long term survival becomes a real question mark as it is affected by so many sources from the macro (solar stability, asteroids, etc.) to the micro (continued viability of the DNA).


Edited by BillP, 29 October 2019 - 09:48 AM.

  • rekokich likes this

#12 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 19,119
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 29 October 2019 - 09:45 AM

FYI, another related publication dealing with the Fermi Paradox --

 

That is not dead which can eternal lie:  the aestivation hypothesis for resolving Fermi’s paradox:  https://arxiv.org/pdf/1705.03394.pdf

 

Aestivation = prolonged state of inactivity or dormancy of an animal during a hot or dry period.



#13 llanitedave

llanitedave

    Humble Megalomaniac

  • *****
  • Posts: 29,958
  • Joined: 25 Sep 2005
  • Loc: Amargosa Valley, NV, USA

Posted 29 October 2019 - 10:02 AM

Bill,

 

Here is an article which precisely addresses your issue:

https://www.cloudyni...i-paradox-r3162

 

I do not think it is scientifically valid to apply ANY statistical method to a problem for which there is only ONE point of data. The Monte Carlo simulation model is then just as imprecise as the Drake model. Until we collect a great deal more information on the Solar system and exoplanets, the only reliable statements we can make are that life is possible, intelligence is possible and, over time, life can evolve from less to more complex forms.

 

Everything else is speculation, where the results of the selected statistical model depend on the balance of optimism and pessimism of the speculator.

 

My personal opinion is that we should not prejudice any investigation with excessive self-regard by assuming that Earth, terrestrial life, or human intelligence are unique in the entire universe.

Very well said.  The referenced paper doesn’t offer any improvements over previous approaches, the authors simply use it to present their own biases and opinions as more desirable.  Postulating a “Fermi’s Paradox” is an exercise in bias on its face, since it involves necessary assumptions that are not necessarily reality — the big one being that a species which evolves the technological ability to survive independently of its ancestral world will somehow find it necessary or desirable to regress back to the need for another planet, when there are so many superior and more convenient sources of energy and resources out there.


  • Miguelo likes this

#14 rekokich

rekokich

    Viking 1

  • *****
  • Posts: 856
  • Joined: 14 Sep 2014
  • Loc: Virginia

Posted 29 October 2019 - 10:17 AM

Two additional considerations:

 

According to Murphy's Law, anything which can go wrong will go wrong. Then, a corollary has to be: anything which can happen will happen. In a universe practically infinite in space and time, it seems reasonable to assume it will happen more than once, though this can not be proven, and is not amenable to valid statistical analysis.

 

Recent trends in technology suggest that the next apex life form is going to be artificial. Just as lower species can never fully understand actions and motivations of a higher species, in a thousand years humans will never be able to comprehend motivations, actions, and evolutionary directions of intelligent, networked robots. If we are ever visited by an alien species, it is almost certainly going to be artificial.


  • Miguelo and Dynan like this

#15 llanitedave

llanitedave

    Humble Megalomaniac

  • *****
  • Posts: 29,958
  • Joined: 25 Sep 2005
  • Loc: Amargosa Valley, NV, USA

Posted 29 October 2019 - 10:23 AM

I am reminded in these exercises of arguments that attempt to downplay the statistical likelihood of any given biological trait appearing through evolution.  After all, the mutations required are so specific, and their likelihood so remote, that any such appearance must be regarded as miraculous.  There are so many ways to misfold a protein, as opposed to the “one true way”, that a mutation that will provide just that specific effect is vanishingly unlikely.  Yet we know biology doesn’t work that way.  There are lots of functional mutations that occur, and there is rarely “one true way” to generate functionality.  Life evolves, generates complexity and diversity, without worrying about our own desire for impossibly difficult bits of Complex Specified Information.

 

I suspect some of our hand-wringing about the vanishingly small probability of other life comes from a similar source.  After all, none of the negative arguments presented overcome the very simple principle of mediocrity.  If an unremarkable planet in an unremarkable system embedded in an unremarkable galaxy can do it, what makes it so remarkable that it can’t happen elsewhere?  I’d rather see real evidence and logic that demonstrates our uniqueness rather than just assumptions that we’re somehow special.


  • rekokich likes this

#16 goodricke1

goodricke1

    Viking 1

  • -----
  • Posts: 585
  • Joined: 18 May 2013
  • Loc: Ireland

Posted 29 October 2019 - 03:11 PM

I am reminded in these exercises of arguments that attempt to downplay the statistical likelihood of any given biological trait appearing through evolution.

 

Why are you assuming that any such attempt is being made? Maybe the authors are stating the present state of knowledge as they see it and it is your prejudice which interprets those statements as 'attempts to downplay'. We are all just guessing at the end of the day and whatever truth dictates will be impervious to personal biases for or against.


  • Dynan likes this

#17 rekokich

rekokich

    Viking 1

  • *****
  • Posts: 856
  • Joined: 14 Sep 2014
  • Loc: Virginia

Posted 30 October 2019 - 04:25 AM

Dave,

The best evidence for our uniqueness is that, based on genetic studies, all life on Earth evolved from a last universal common ancestor (LUCA), a single cell hydrothermal vent prokaryote, which appeared more than 3.9 billion years ago.

https://phys.org/new...ed-earlier.html

There is no other lineage of life on Earth so far detected.

If appearance of life were a common occurrence, a number of different genetic lineages should have developed in addition to LUCA. During the billions of years since, only viruses and prions evolved, which do not really qualify as independent life forms. These agents do not form cells, cannot produce their own energy, do not grow, and can not propagate outside a host cell.

The single origin of all life on Earth is a serious problem for the hypothesis that alien life must be common because life appeared so early in Earth's history.

In the end, ignorance can not be illuminated with any statistical model based on a single data point. But, if we were to discover other lineages of life on Earth or elsewhere in the Solar System, no matter how simple - that would be truly monumental. Recent studies have shown evidence of organic molecules in salty water expelled by Enceladus's geysers, suggesting the possibility of a hydrothermal vent biosphere. Magnetic field data from Europa indicate that it also has a subsurface salty liquid ocean. Another course of investigation would be to search for biomarkers in exoplanet atmospheres.

More WILL be revealed. Patience is a virtue; and virtue is its own reward.

Rudy


  • llanitedave and russell23 like this

#18 Dynan

Dynan

    Soyuz

  • *****
  • Posts: 3,570
  • Joined: 11 Mar 2018
  • Loc: NOLA

Posted 30 October 2019 - 09:41 AM

Patience is a virtue; and virtue is its own reward.

Rudy

While I agree with your assessment, and succinct view of virtue...

 

vulture.png


  • llanitedave and rekokich like this

#19 llanitedave

llanitedave

    Humble Megalomaniac

  • *****
  • Posts: 29,958
  • Joined: 25 Sep 2005
  • Loc: Amargosa Valley, NV, USA

Posted 30 October 2019 - 10:27 AM

Why are you assuming that any such attempt is being made? Maybe the authors are stating the present state of knowledge as they see it and it is your prejudice which interprets those statements as 'attempts to downplay'. We are all just guessing at the end of the day and whatever truth dictates will be impervious to personal biases for or against.

I’m not assuming the authors are making the assumption.  I am noticing some general parallels.



#20 llanitedave

llanitedave

    Humble Megalomaniac

  • *****
  • Posts: 29,958
  • Joined: 25 Sep 2005
  • Loc: Amargosa Valley, NV, USA

Posted 30 October 2019 - 10:59 AM

Dave,

The best evidence for our uniqueness is that, based on genetic studies, all life on Earth evolved from a last universal common ancestor (LUCA), a single cell hydrothermal vent prokaryote, which appeared more than 3.9 billion years ago.

https://phys.org/new...ed-earlier.html

There is no other lineage of life on Earth so far detected.

If appearance of life were a common occurrence, a number of different genetic lineages should have developed in addition to LUCA. During the billions of years since, only viruses and prions evolved, which do not really qualify as independent life forms. These agents do not form cells, cannot produce their own energy, do not grow, and can not propagate outside a host cell.

The single origin of all life on Earth is a serious problem for the hypothesis that alien life must be common because life appeared so early in Earth's history.

In the end, ignorance can not be illuminated with any statistical model based on a single data point. But, if we were to discover other lineages of life on Earth or elsewhere in the Solar System, no matter how simple - that would be truly monumental. Recent studies have shown evidence of organic molecules in salty water expelled by Enceladus's geysers, suggesting the possibility of a hydrothermal vent biosphere. Magnetic field data from Europa indicate that it also has a subsurface salty liquid ocean. Another course of investigation would be to search for biomarkers in exoplanet atmospheres.

More WILL be revealed. Patience is a virtue; and virtue is its own reward.

Rudy

I don’t see the single lineage argument as compelling.  After all, there is only one surviving lineage in the genus Homo, even though we know that hominids were once far more diverse, and in several other evolutionary lineages groups that were once diverse have since gone through major choke points.  We don’t know whether there was a single origin of life on Earth, but a single surviving lineage is compatible with both single and multiple origin hypotheses.  A multiple origin model would still have set all the lineages in competition against one another, with the likelihood that one eventually came to dominate, and then overwhelm, the others.  A single origin model might imply not rarity of origin but rapidity of spread, such that the first life form to appear would occupy all available niches to the point that there would be no opportunities for a second origin to become established.

 

 I can see the possibility of both models being valid in different circumstances—on some worlds life would all be descendants of a LUCA, on others there might be two or more independent lineages coexisting.  

 

Like planet formation itself, biological evolution is chaotic, dynamic, unpredictable, yet ultimately tractable.  The possibilities are not infinite, but they are vast.  That’s part of the reason I think it might be a mistake to assume either that we’re alone in the galaxy, or that others would be essentially similar to us.

 

 I agree that patience will likely be rewarded.  I suspect those rewards will include a number of surprises.



#21 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 19,119
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 30 October 2019 - 02:53 PM

Bill,

 

Here is an article which precisely addresses your issue:

https://www.cloudyni...i-paradox-r3162

 

I do not think it is scientifically valid to apply ANY statistical method to a problem for which there is only ONE point of data. The Monte Carlo simulation model is then just as imprecise as the Drake model. Until we collect a great deal more information on the Solar system and exoplanets, the only reliable statements we can make are that life is possible, intelligence is possible and, over time, life can evolve from less to more complex forms.

 

Everything else is speculation, where the results of the selected statistical model depend on the balance of optimism and pessimism of the speculator.

 

My personal opinion is that we should not prejudice any investigation with excessive self-regard by assuming that Earth, terrestrial life, or human intelligence are unique in the entire universe.

 

As far as everything being speculation, well that is true, even within the link you provided (I would not consider the initial premise valid that indirect evidence allows any hypothesizing, instead it only allows more non-evidentiary speculating).  Nothing relative to there being life present elsewhere in the universe at all is evidenced based.  So any discussion of possible life in the universe is 100% speculation.  No one even knows what is necessary for abiogensis for goodness sake.  So one saying we are unique or are not unique, well both are speculative although it can be said so far, after many decades of searching, only life on Earth is evidenced.  But even here, no evidence on how it started, which would be critical to speculate with any degree of confidence if those abiogenisis conditions might exist elsewhere.

 

Btw, at the end of the section of the link you provided discussing the Oxford Model it is mentioned that in a universe of 200B galaxies the likelihood of ETI would be 1.  Not sure that is relevant to the Drake Equation as that was only meant to model our galaxy.  Tempting to try to extend to the entire universe, but not relevant IMO and opens new cans of worms.  Best to stay within scope.  Actually, any non-zero probability for anything, given an infinite universe, will always be one so the numbers game becomes a problem when infinity is in the room and you really then need to nail down whether any of the prior assumptions in you equation can indeed be possible.  So as example, will technological civilizations ever last long enough to be meaningful for detecting any of their radiations?  Is it possible for a civilized species to exist for more than a few thousand or million years?  It indeed may not be.  So when you factor things like that, then presuming that the time for life to get to civilization takes eons  longer than that civilization can hope to survive, affects the 200B case cited.  I think it was quite wise of Drake to keep the argument framed to our galaxy as all the variables are unknowns really.  Extending the argument further is just folly.

 

I also do not think that statement in the link you provided that says the Fermi Paradox "infers that ETI do not exist because we have no evidence of them" is a valid point.  The paradox does not infer that so the argument that follows is moot.  Fermi's paradox simply states there appears to be a paradox -- if there are potentially so many, why not detectable?  Many have forwarded plausible rationales for this, including the Oxford folks in their discussion.  


Edited by BillP, 30 October 2019 - 08:29 PM.

  • Sleep Deprived likes this

#22 Sleep Deprived

Sleep Deprived

    Mariner 2

  • *****
  • Posts: 211
  • Joined: 17 Apr 2019
  • Loc: Seattle Area

Posted 30 October 2019 - 08:05 PM

If given enough time to consider his/her response, I would expect any scientist would not say "ET doesn't exist", but say something more along the lines of "We have no evidence for ET".  We can all imagine that life exists elsewhere, and we can search for it, and we can rationalize all we want about why we aren't finding it.  In the end, we simply don't know.  We have no current evidence, but that could all change tomorrow.  Either we will never know that ET exists, or we will know that it does.  We'll never know that it DOES NOT exist.  If we are, in fact, unique, we will probably always be searching in vain for others.  Because that cosmic handshake could happen tomorrow.  We can have all the scientific models possible, but the only thing that will be a positive result is the proverbial cosmic handshake.  We won't know if there's ET until we KNOW there's ET.  Let's keep looking, though, in every place possible.


  • BillP likes this

#23 EJN

EJN

    Aurora

  • *****
  • Posts: 4,534
  • Joined: 01 Nov 2005
  • Loc: Between what is and what's not there

Posted 30 October 2019 - 08:06 PM

Here's my updated version:  N = ?


  • BillP likes this

#24 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 19,119
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 30 October 2019 - 08:25 PM

Here's my updated version:  N = ?

 

waytogo.gif waytogo.gif Now that is a scientifically correct statement as I get what you mean.  To be accurate, since we positively know there is at least 1 civilization in the Milky Way would have to put it more like: N<1=FALSE; N=1=TRUE; N>1=?.


Edited by BillP, 30 October 2019 - 08:26 PM.


#25 rekokich

rekokich

    Viking 1

  • *****
  • Posts: 856
  • Joined: 14 Sep 2014
  • Loc: Virginia

Posted 31 October 2019 - 02:48 AM

Dave,

You are correct. The single lineage argument is unconvincing because it is yet another example of false inference.

The LUCA study showed that currently known terrestrial life forms have a common origin in a hydrothermal vent prokaryote. But, prokaryotic cells already manifest very substantial structural complexity in the form of double plasma membranes, cell walls, pilli, flagella, cytoskeletons, nucleoids (self-replicating DNA), ribosomes (self-replicating RNA), plasmids (self-replicating rings of DNA). These cells communicate environmental conditions to each other via chemical mediators (quorum sensing), and exchange genetic information with adjacent cells through the pilli (e.g. antibiotic resistance).

Numerous structural elements, dual genetic composition, regulated gene expression, and behavioral sophistication indicate that LUCA itself was not a primordial life form, but rather a merger product of MULTIPLE precursors.

The single lineage argument is easily refuted by:
- Incomplete investigation of all terrestrial life forms,
- Extinction of selected lineages caused by interspecies competition or environmental factors, and
- Merger of multiple primordial lineages into more complex biological agents.

Here are several links you might find interesting:
https://www.ncbi.nlm...books/NBK26876/
https://www.annualre....micro.55.1.165
https://www.scienced...006778?via=ihub

PS

For the record, I am not entirely convinced that patience is a virue, and that virtue is its own reward. I put that up as a conceptual challenge.
In this instance, we have no choice but to be patient. And, I don’t feel particularly rewarded while waiting for the answer.

 




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics