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RobertTierney
2012-Jun-24, 09:31 PM
Just a quick intro about myself. I am only a fan of astronomy... I'm no one... So please take my ideas with a grain of salt...

I have heard many ideas about why we have not found proof for E.T. And I don't think anyone wants to discuss a really daunting problem, time and space (geography)...

Let me suggest two general problems or variables
A- In the long history of the Earth (several billion years) a self aware technologically capable species (us) have only occupied the biology of this planets existance for 20,000- to maybe 2.5 million years ago... And we constitute a minor percentage of earth time... Meaning perhaps that self aware technologically capable species might rise on earth like planets at a slow or difficult to predict time frame... meaning that earth like planets would probably not share self ware technologically capable species at the same time... Of course there are billons of stars (x) billions of galaxies... Greatly increasing the chance of simutaneous co existance...

But this is the second problem variable

B- Geography... There are so many stars and galaxies that of course signals traveling at the speed of light could not bridge in time or power... And if there are space faring civilizations... the geography problem increases the odds that there is so much to explore... that they would never bump into another civilization... Take the earth for example... While it is true that we are increasing world population rapidly... it seems like a very slow process of colonizing other worlds... Mars might one day be colonized but it would still take time to max out the surface of mars with population growth. And with the increasing population growth... it would probably take time to use or fill up Earth like planets...

So what if self aware technologically capable civilizations exist in some abundance at the same time as we do... But will not likely bump into eachother because there are "Too many grains of sand"...

x
Bob Tierney

Jens
2012-Jun-25, 03:43 AM
To be honest, I don't really see anything "against the mainstream" in your idea. I think that the tremendous space between stars is one of the well accepted factors behind our not meeting other intelligent species.

primummobile
2012-Jun-25, 02:56 PM
A- In the long history of the Earth (several billion years) a self aware technologically capable species (us) have only occupied the biology of this planets existance for 20,000- to maybe 2.5 million years ago... And we constitute a minor percentage of earth time... Meaning perhaps that self aware technologically capable species might rise on earth like planets at a slow or difficult to predict time frame... meaning that earth like planets would probably not share self ware technologically capable species at the same time... Of course there are billons of stars (x) billions of galaxies... Greatly increasing the chance of simutaneous co existance...



I don't think that is very outlandish. It's been proposed that intelligent civilizations only transmit radio signals for a brief period of time. That can either mean that they stop using radio altogether in favor of a more advanced technology, or that they stop using radio in a high-power low-gain format like what we use on earth.

JustAFriend
2012-Jun-25, 06:25 PM
We are a very tiny dot....

http://www.geekosystem.com/wp-content/uploads/2011/02/radio_broadcasts1.jpeg

John Mendenhall
2012-Jun-26, 01:34 AM
I think you're quite correct. You might contact a Moderator about moving this thread to Q&A, or Astronomy, or such.

Best regards, John M.

ToSeek
2012-Jun-26, 01:50 AM
Moved from ATM to Life in Space, with a one-week redirect.

Selfsim
2012-Jun-26, 03:53 AM
I have heard many ideas about why we have not found proof for E.T. And I don't think anyone wants to discuss a really daunting problem, time and space (geography)
Hi Robert;

Well, I'd say the really daunting problems no-one wants to discuss are:

1) The uniqueness of life on Earth can only be falsified with the first confirmed exo-life discovery;

2) The existence of exo-life in the universe, can never be practically falsified with multiple negative discoveries, no matter how vast in number these are;

3) The numbers of habitable environments throughout the universe, tells us nothing about the uniqueness or otherwise, of life in the universe, until a single instance of exo-life is discovered locally, in an exo-habitable zone;

4) The only self aware civilisation we know of, has no choice other than to model life on life's evidence-based uniqueness. By necessity, this biases the search criteria, and cannot be removed by analysis to produce a meaningful predictive result;

5) It is not practically feasible to remotely detect exo-life over light-year distances (until exo-life is discovered locally);

6) It is not possible to retrace the environmental history of Earth with sufficient precision, in order to predict exo-life emergence from exo-environments;

So, with all that being said, it seems that the problems you mention, all originate from a belief that whatever happened here on Earth, will happen again which is not supported by any direct physical evidence.

Abandon the belief, and the problems you mention of time and space (geography), disappear in an instant !

Regards

whimsyfree
2012-Jun-26, 08:15 AM
Hi Robert;

Well, I'd say the really daunting problems no-one wants to discuss are:

1) The uniqueness of life on Earth can only be falsified with the first confirmed exo-life discovery;

2) The existence of exo-life in the universe, can never be practically falsified with multiple negative discoveries, no matter how vast in number these are;


Ditto unicorns, mermaids and manticores. I think the reason no-one wants to discuss your first two points is that they are trivial.


3) The numbers of habitable environments throughout the universe, tells us nothing about the uniqueness or otherwise, of life in the universe, until a single instance of exo-life is discovered locally, in an exo-habitable zone;


"Locally" doesn't make much sense in this context. Exo-habitable zones are not local.


4) The only self aware civilisation we know of, has no choice other than to model life on life's evidence-based uniqueness. By necessity, this biases the search criteria, and cannot be removed by analysis to produce a meaningful predictive result;


If we define life consistently to refer to certain characteristics and behaviors that are of interest to us, then there is no bias. That this might lead to our over-looking uninteresting life forms is not a great problem; that we might over-look lifeforms that we would have been interested in if we had known such things could exist is more worrisome.


5) It is not practically feasible to remotely detect exo-life over light-year distances (until exo-life is discovered locally);


Why not? With sufficiently powerful instruments we could image exoplanet surfaces. Less powerful instruments could detect chemical disequilbria that would give at least good hints of life.



6) It is not possible to retrace the environmental history of Earth with sufficient precision, in order to predict exo-life emergence from exo-environments;


That is not a matter of retracing the environmental history of Earth but chemistry. In principle, if we can determine the rate at which life emerges under certain conditions, such as by laboratory experiments, then we would be justified in applying that to exo-planetary environments.


So, with all that being said, it seems that the problems you mention, all originate from a belief that whatever happened here on Earth, will happen again which is not supported by any direct physical evidence.

Abandon the belief, and the problems you mention of time and space (geography), disappear in an instant !


I agree that most of the so called Fermi paradox is just the collision between the conviction that Earth-like life not only exists out there but is plentiful, and the lack of any evidence for this.

Selfsim
2012-Jun-26, 09:45 AM
Ditto unicorns, mermaids and manticores. I think the reason no-one wants to discuss your first two points is that they are trivial.Well Ok ...cool. Nothin' like stating non-speculative science in order to distinguish speculation eh ? ...


"Locally" doesn't make much sense in this context. Exo-habitable zones are not local.Semantics. 'Exo' in this instance, was intended as excluding specifically Earth-based.


If we define life consistently to refer to certain characteristics and behaviors that are of interest to us, then there is no bias. I think you just defined 'bias' for us !
That this might lead to our over-looking uninteresting life forms is not a great problem; that we might over-look lifeforms that we would have been interested in if we had known such things could exist is more worrisome.Why would it be 'worrisome' if the approach isn't biased ?



5) It is not practically feasible to remotely detect exo-life over light-year distances;Why not? With sufficiently powerful instruments we could image exoplanet surfaces.Do such instruments exist and is there a confirmed unique relationship between what they can detect over light-year distances, and the presence of exo-life ? If not, then it is not practically feasible to remotely detect exo-life over light-year distances ....


Less powerful instruments could detect chemical disequilbria that would give at least good hints of life.Chemical disequilibria now necessarily provides 'good hints' of life then ?


That is not a matter of retracing the environmental history of Earth but chemistry. In principle, if we can determine the rate at which life emerges under certain conditions, such as by laboratory experiments, then we would be justified in applying that to exo-planetary environments.I'm reminded of those shrimp marketed as 'Sea Monkeys' (http://en.wikipedia.org/wiki/Sea_monkeys) ... just add water ! :)

Cheers

Noclevername
2012-Jun-26, 08:54 PM
So, with all that being said, it seems that the problems you mention, all originate from a belief that whatever happened here on Earth, will happen again … which is not supported by any direct physical evidence.
Regards

I would say rather that it's based on the hypothesis that what happened here could happen elsewhere.

whimsyfree
2012-Jun-27, 01:39 AM
Well Ok ...cool. Nothin' like stating non-speculative science in order to distinguish speculation eh ? ...


I don't understand that.


Semantics. 'Exo' in this instance, was intended as excluding specifically Earth-based.

The question was what you meant by local.


I think you just defined 'bias' for us !

I didn't define anything.


Why would it be 'worrisome' if the approach isn't biased ?

Because there are things to worry about other than bias. Such as ignorance.


Do such instruments exist and is there a confirmed unique relationship between what they can detect over light-year distances, and the presence of exo-life ? If not, then it is not practically feasible to remotely detect exo-life over light-year distances ....


That's wrong. The fact that an instrument hasn't been built yet does not imply that it wont be. There are already designs for space based telescopes that could resolve an Earth sized planet. Their construction will have to wait for the deployment technology and economics to advance.



Chemical disequilibria now necessarily provides 'good hints' of life then ?

I don't know about "necessarily", but it's one of the means commonly suggested in the literature. You should read the literature some time.


I'm reminded of those shrimp marketed as 'Sea Monkeys' (http://en.wikipedia.org/wiki/Sea_monkeys) ... just add water ! :)


I don't see the connection but I'll take that as agreement.

Selfsim
2012-Jun-27, 11:19 PM
1) The uniqueness of life on Earth can only be falsified with the first confirmed exo-life discovery;

2) The existence of exo-life in the universe, can never be practically falsified with multiple negative discoveries, no matter how vast in number these are;
Ditto unicorns, mermaids and manticores. I think the reason no-one wants to discuss your first two points is that they are trivial.

Well Ok ...cool. Nothin' like stating non-speculative science in order to distinguish speculation eh ? ...
I don't understand that.
The point is that the 'numbers game' (ie: citing the number of 'habitable' exo-planets in the observable universe), leads nowhere definitive. Only speculative arguments result from such analysis. 'Hypotheses' so formed, are highly questionable as most are practically untestable, and are thus excluded from scientific analysis (read: belief based).



3) The numbers of habitable environments throughout the universe, tells us nothing about the uniqueness or otherwise, of life in the universe, until a single instance of exo-life is discovered locally, in an exo-habitable zone;
"Locally" doesn't make much sense in this context. Exo-habitable zones are not local.
Semantics. 'Exo' in this instance, was intended as excluding specifically Earth-based.The question was what you meant by local. Same thing .. 'local' is intended as not from Earth, but within practical reach of Earth. Unless its blatantly, obviously alive, (like a moving ET staring straight back into Curiosity's cameras), life tests are biological tests which must be applied directly on the sample being tested. This can only be done by return sample or onsite, on a limited number of bodies within the Solar System.


Because there are things to worry about other than bias. Such as ignorance.The most generalised models of 'life' we can come up with, may still be biased because they are derived from instances of only Earth-life, yet, it is theoretically conceivable that other life could still exist which is based on other chemistries. Such other 'life' still fits within that generalised model, yet our search strategy targets seeking only Earth-like life. The 'other chemistry' life might well be overlooked because of the bias of remotely searching for only Earth-like life (metabolic by-products and liquid water solvents). The generalised theoretical model removes the 'ignorance' factor in theory, but a biased search strategy such as remotely looking for 'Earth-like' life, reintroduces the likelihood of 'other chemistry' life being overlooked.

This is not a criticism, as one can't predict anything much about how a speculated life-form might appear or behave (in order for it to be detected). The point is that the search strategy is not presently being driven by the theoretical life model (although this may be slowly changing with acknowledgement for example, that other liquid solvents may be a substitute for life). A divergence of target environments away from 'Earth-like' however, highlights the current data paucity situation, which should be the primary objective of the strategy to correct this objective cannot be met via remote spectrographic searches of the Cosmos (at light-year distances). Even if negative results are returned, it may be corrected however, by focusing on the exploration of the local planet/Solar system environment.



Do such instruments exist and is there a confirmed unique relationship between what they can detect over light-year distances, and the presence of exo-life ? If not, then it is not practically feasible to remotely detect exo-life over light-year distances ....That's wrong. The fact that an instrument hasn't been built yet does not imply that it wont be. There are already designs for space based telescopes that could resolve an Earth sized planet. Their construction will have to wait for the deployment technology and economics to advance. The instrument is one thing, but not the main point, as clearly resolution will improve over time (whilst approaching theoretical and practical design limits). Say such an instrument is built in the future. Remote observations are obtained by using it. What then ? How can one then conclude exo-life is present, if one cannot apply biological tests directly to the sample, (over light-year distances), with the view of confirming whether what our instrument observed, is in any way associated with life ? If no prior reference model exists for non-Earth like exo-life, there is nothing which can exclude other explanations for the observations. Even with the Earth-like reference model, non biogenic sources still cannot be excluded. There are presently only a very limited number of ways to diagnose life ... and none of these can be applied over light-year distances. Its even tricky to diagnose some Earth-life species locally (eg: viruses etc).
The test is all-important for verification (or falsification). If the test cannot be applied (for practical reasons), then a conclusion cannot be reached and it is thus not feasible, (from a purely practical perspective), to remotely detect exo-life.



Chemical disequilibria now necessarily provides 'good hints' of life then ?I don't know about "necessarily", but it's one of the means commonly suggested in the literature. You should read the literature some time.'Suggestions' are speculative and by no means conclusive. Critical thinking is mandatory in Science, although it seems perhaps, less frequently exercised.
There are classes of chemical reactions which oscillate around equilibrium points, making frequent excursions far from such equilibria, and back again. How does one exclude these categories in order to conclude 'life' ?


I don't see the connection but I'll take that as agreement.If you don't see the connection, then agreement would be a tad premature don't you think ?

whimsyfree
2012-Jun-28, 01:19 AM
The point is that the 'numbers game' (ie: citing the number of 'habitable' exo-planets in the observable universe), leads nowhere definitive. Only speculative arguments result from such analysis. 'Hypotheses' so formed, are highly questionable as most are practically untestable, and are thus excluded from scientific analysis (read: belief based).

Same thing .. 'local' is intended as not from Earth, but within practical reach of Earth. Unless its blatantly, obviously alive, (like a moving ET staring straight back into Curiosity's cameras), life tests are biological tests which must be applied directly on the sample being tested. This can only be done by return sample or onsite, on a limited number of bodies within the Solar System.


So intelligible signals, artifacts, and other products of life don't count? With your narrow views you would have to reject the existence of pre-historic life. Fossils are just funny shaped rocks, after all, and not living creatures to which biological tests can be "applied directly". Fortunately every informed researcher takes a much broader view of how life may be detected.


The instrument is one thing, but not the main point, as clearly resolution will improve over time (whilst approaching theoretical and practical design limits). Say such an instrument is built in the future. Remote observations are obtained by using it. What then ? How can one then conclude exo-life is present, if one cannot apply biological tests directly to the sample,


The red edge, seasonal changes in ground cover, free oxygen, free oxygen and free methane, etc. City lights and radio broadcasts might be a clue too, if the life is intelligent.

Selfsim
2012-Jun-28, 07:42 AM
So intelligible signals, artifacts, and other products of life don't count? With your narrow views you would have to reject the existence of pre-historic life. Fossils are just funny shaped rocks, after all, and not living creatures to which biological tests can be "applied directly". Fortunately every informed researcher takes a much broader view of how life may be detected.Are you asking a question ? ... Or are you criticising a straw-man you have constructed from some wild guesses about what my 'views' might be ?



The instrument is one thing, but not the main point, as clearly resolution will improve over time (whilst approaching theoretical and practical design limits). Say such an instrument is built in the future. Remote observations are obtained by using it. What then ? How can one then conclude exo-life is present, if one cannot apply biological tests directly to the sample, The red edge, seasonal changes in ground cover, free oxygen, free oxygen and free methane, etc. ... All of which can be generated by non-biological sources.
City lights and radio broadcasts might be a clue too, if the life is intelligent.'A clue' ?? Are you serious ?

whimsyfree
2012-Jun-28, 07:55 AM
Are you asking a question ? ... Or are you criticising a straw-man you have constructed from some wild guesses about what my 'views' might be ?


The question mark you can take as an indication of a question. There is no "strawman" -- you have started your views quite clearly: "life tests are biological tests which must be applied directly on the sample being tested". Are you retreating from that?


... All of which can be generated by non-biological sources.

In principle, anything can. It is just a matter of weighing the evidence. Not all evidence for life is "biological tests which must be applied directly on the sample being tested".


'A clue' ?? Are you serious ?

You don't think so? I'm starting to think your position is so ridiculous I should be troubled discussing it further.

Selfsim
2012-Jun-28, 09:52 PM
So intelligible signals, artifacts, and other products of life don't count?
The question mark you can take as an indication of a question. OK hypothetically then, the answer is:
i) intelligible signals: depends on the nature of the signal, detection and interpretation methodologies used, etc. I've voluntarily acknowledged that positive SETI signal detection results may also suffice as far as remote detection of intelligent life, multiple times, in multiple previous posts;
ii) artifacts: depends on the confirmation method and the interpretation;
iii) other products: depends on what other products you are speaking of (amongst a myriad of other details).


There is no "strawman" -- you have started your views quite clearly: "life tests are biological tests which must be applied directly on the sample being tested". Are you retreating from that?No. What I originally stated was:
5) It is not practically feasible to remotely detect exo-life over light-year distances (until exo-life is discovered locally)With the mundane addition of SETI detection under the very specific conditions mentioned above, nothing in this statement has changed as a result of the ideas you raise.
Then, the complete context from which you quoted my words was:
Unless its blatantly, obviously alive, (like a moving ET staring straight back into Curiosity's cameras), life tests are biological tests which must be applied directly on the sample being tested. This can only be done by return sample or onsite, on a limited number of bodies within the Solar System.Under the purely hypothetical scenarios you have implied, I would classify the matters you raise as being 'blatantly obvious'. That is yet another hypothetical non-issue as far as I'm concerned. The issue is how you intend to demonstrate the existence of such evidence in order to justify the construction of a method for detection ... and, at present, it is either (i) not pratically feasible to bring such evidence to bear for observations over light-year distances (artifacts, etc) or; (ii) if the evidence is of the type of inferred biogenic chemical by-products, then exclusion of other natural sources of these would be required, and we do not yet have complete knowledge of all the complex processes capable of producing such products.


... All of which can be generated by non-biological sources.In principle, anything can. It is just a matter of weighing the evidence. Not all evidence for life is "biological tests which must be applied directly on the sample being tested".In the scientific context, the search for life, is the test for a Universal Theory of Life. Under your hypothetical, all remotely detectable 'artifacts' would not necessarily be direct evidence of life (as I said .. it depends on analysis /confirmation methods and interpretations which once again, comes back to an Earth-life model instance of one which is merely reinforcing the bias of the approach, as discussed and covered in my point #4). Positive biological sampling test results however, would constitute direct evidence leading to scientific progress in the exo-life area and would also cover your hypothetically conjectured scenarios.

You don't think so? I'm starting to think your position is so ridiculous I should be troubled discussing it further.You are free to contribute to this thread. If your opinions prevent you from doing so further, then that would be your choice.

I am quite happy to abandon this discussion as well. I have no interest in arguments based on purely hypothetical conjecture.

Ara Pacis
2012-Jun-29, 05:54 PM
B- Geography... There are so many stars and galaxies that of course signals traveling at the speed of light could not bridge in time or power... And if there are space faring civilizations... the geography problem increases the odds that there is so much to explore... that they would never bump into another civilization... Take the earth for example... While it is true that we are increasing world population rapidly... it seems like a very slow process of colonizing other worlds... Mars might one day be colonized but it would still take time to max out the surface of mars with population growth. And with the increasing population growth... it would probably take time to use or fill up Earth like planets...

Are you assuming we or an alien analog would fill up Mars before expanding to a new planet? Why?