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Jarad
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Reged: 04/28/03

Loc: Atlanta, GA
Re: The silence is deafening.... new [Re: dickbill]
      #5432779 - 09/21/12 02:00 PM

Quote:

Like for any simulation, total accuracy is impossible and some simplifications must be made, otherwise the model could take as long as the real thing to occur.




The real thing in terms of protein folding occurs in fractions of a second.

Quote:

Conditions that depends on the orbital parameters can be estimated by observation, again with more or less accuracy.



Observation of what? If we had a set of planets with life and a set without, we could observe the orbital parameters and see if there are consistent differences. But with an N of 1, we can't.

Quote:

I think that several years observing a putative Earth orbiting a Sun at that distance with big mirrors in interferometry mode (milliseconds arc resolution as mentioned above), could yield some 'compatible markers', like Oxygen, some greenish hint in the spectra, maybe some specular reflection from the oceans directed to us.





We don't have any scopes that could resolve any of those things right now.

And just seeing green won't mean anything - there are plenty of inorganic chemicals that can look green, and alien life won't necessarily use a green protein in their photosynthesis - they could evolve around a molecule that captures a different wavelength. Neither will seeing reflections - things other than water can be reflective.

More importantly, not seeing those things doesn't mean that life does not exist there. We can't even rule out life under the ice sheets of Europa, which is much closer. How could we rule out life on an exoplanet based on not seeing green from many lightyears away? What if their chlorophyll equivalent molecule is more efficient, and looks black (absorbing all visible wavelengths)?

Jarad


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Jarad
Postmaster
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Reged: 04/28/03

Loc: Atlanta, GA
Re: The silence is deafening.... new [Re: Jarad]
      #5432803 - 09/21/12 02:06 PM

There is a gap in our understanding of the origin of life.

We can simulate in the lab early conditions with simple compounds, hit them with static discharges, and see the production of complex organic molecules that could be the precursors for life.

Once we have a self-replicating cell, we can drop it in that soup and watch it replicate and evolve.

But between the two there are at least 2 big steps that are not yet well understood: the generation of simple self-replicating molecules, and the leap to an enclosed system with a membrane to keep all the required parts together for self-replication.

There are lots of hypotheses about how these steps occurred (surface chemistry on clays, etc.), but these are all speculative. We don't know exactly how it happens or how long it "typically" takes.

As for declaring out current "theory of life" dead if we find 2 exoplanets without life, I would say that is false for 2 reasons:
1 - one or two examples isn't enough to disprove such a theory.
2 - we don't really have a developed theory to disprove.

Jarad


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llanitedave
Humble Megalomaniac
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: The silence is deafening.... new [Re: Jarad]
      #5432870 - 09/21/12 02:41 PM

Quote:


2 - we don't really have a developed theory to disprove.






And that's a biggie.

It may well be that there are a number of processes that can lead to life from nonlife. There may be only one. If we do succeed in doing it the lab, my first guess will be that we've stumbled on one of several.

This is one of those situations where it seems to me that theory is not primary to observation, probably something that Popper would have disputed. We're creating the theory as we do our experiments, one local hypothesis at a time.


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: The silence is deafening.... new [Re: Jarad]
      #5433038 - 09/21/12 04:04 PM

Oooooo! I can finally add something scientific.....

You two wrote, "I think that several years observing a putative Earth orbiting a Sun at that distance with big mirrors in interferometry mode (milliseconds arc resolution as mentioned above), could yield some 'compatible markers', like Oxygen, some greenish hint....We don't have any scopes that could resolve any of those things right now. And just seeing green won't mean anything - there are plenty of inorganic chemicals that can look green..."


A half century ago...possibly before you two were born...necessity required me at age 15 to make my own telescope...the whole thing...grind/polish/cut/mount/cast iron weights...two years later, I ended up with an 8 inch F8 Newtonian with 1/2 wavefront error...maybe even a whole wave error...it was so bad when I got it back from Clausing who coated it for me, they put in a note disclaiming responsibility for all the sleeks. Seems one is suppose to clean the former grinding slurry away before going to the next finest grade. (would be a quarter century later when I stopped it down to an F11 6 inch that I discovered I could see the Cassini division)....

anyway, I digress....I turned this behemoth at Mars one summer, and I saw GREEN. I saw a definitie gray-greens. I can only think of three reasonable explanations:
1. a contrast effect of the darker areas against the reddish area
2. there's green cholorophyll on Mars
3. there were so many sleeks on the mirror, it was prismatic

Compared to me....you are mere theoreticians. I did real science!

Otto

Edited by Otto Piechowski (09/21/12 05:11 PM)


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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: The silence is deafening.... new [Re: llanitedave]
      #5433052 - 09/21/12 04:13 PM

There is not one theory, you are right, but many, BUT the thing is that they all converge toward a necessary autocatalytic molecular entity. Once this tipping point is reached, with autocatalytic molecular replicators trapped into oily vesicles, the transition from prebiotic to biotic is, i would say, not completely crazy.

Just following wikipedia links, you' ll see the hypothesis of a pre-RNA world: the PAH-World, (Polycyclic Aromatic Hydrocarbon, believed to be abundant on early earth, and even in the martian meteorit ALH, if i recall) that would promote the pre-RNA world through the steps explained in http://en.wikipedia.org/wiki/PAH_world_hypothesis
A transient pre-RNA world would probably be short-lived, as it cannot compete well with the first really autocatalytic RNA forms.
http://en.wikipedia.org/wiki/RNA_world_hypothesis
So now the RNA/TNA/GNA-replicators World trapped with amino-acids inside lipid vesicle is considered as the critical step, and I guess we can call this assembly THE 'protocell'. The emphasis is not anymore how do we get to this protocell but how do we get to the TNA/GNA/RNA replicator. In addition to the PAH, a pre-rna Lipid World has also been proposed.


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moynihan
Carpal Tunnel


Reged: 07/22/03

Loc: Lake Michigan Watershed
Re: The silence is deafening.... new [Re: dickbill]
      #5433122 - 09/21/12 04:56 PM

Perhaps the ESA will some day revive the Darwin Array project. Using multiple satellites (to create a long baseline, essentially one big instrument in multiple parts) the ideas is to do spectographic analysis of "goldilocks zone" candidates around other stars. It would look for dynamic atmospheres with oxygen and water and trace elements that hypothetically require input from a biosphere to exist (ala Lovelock/Margulis etc).

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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: The silence is deafening.... new [Re: moynihan]
      #5433203 - 09/21/12 06:03 PM

" 2 - we don't really have a developed theory to disprove."

Hmm, yes, let's say we have a range of possibilities, instead. If the Moon is that much critical, for example, well, we might never find an earth-like exoplanet couple in our galaxy, so in this case I agree than NOT finding life in an exoplanet otherwise well situated in the goldilock zone would prove nothing.
But it's the WE, almost 6PM, clear skies, time to setup the scope. Clear sky guys.


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: The silence is deafening.... new [Re: dickbill]
      #5433306 - 09/21/12 07:21 PM

Three hours, and no response by you mere theoreticians to my sage comments about doing actual science with exquisite astronomical equipment?

Just for that….I will now add a word of philosophy. (“A word” of philosophy, Otto? That’ll be the day!)

The ancient Greek language was more flexible than English. For example, its common verbs each had between two hundred and three hundred forms whereas in English our verbs have between fifty and a hundred forms. This flexibility allowed the speakers of Greek to articulate issues with fine and helpful degrees of nuance, conducive to displaying truth.

This degree of nuance can be seen in how the Greek language handled two topics we are addressing here, life and theory (life, as in "extra-terrestrial life" and theory, as in "you mere theoreticians"). In fact, the Greek language connects the two concepts of life and theory in an interesting way.

Greek has two words for life, bios (pronounced “bee-ohss”) and zoa (pronounced “zoh-ay”). Zoa was used to refer to the word life in the sense we have been discussing it here; i.e. living things. Bios was often used to refer to the type of life a person lived. The difference, then, between these uses of zoa and bios was similar to the distinction we have in English between “life” and “a life” as in the trite phrase, “get a life”. Bios was often attached to other words such as politikos as in bios politikos (the active/public life) and, relevant to our second topic, theoretikos as in bios theoretikos (the thinking/contemplative life).


But…I digress……


...we, you and I, stargazers and scopists all, we who consider looking through a telescope for hours on end getting bitten by mosquitoes, getting frost bite on our toes, and/or going without sleep, to be having just a fine time...the rest of the non stargazing world is pretty sure we, you and I, do not have, bioi (pronounced bee-oy; the plural of bios).

Edited by Otto Piechowski (09/21/12 07:45 PM)


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deSitter
Still in Old School


Reged: 12/09/04

Re: The silence is deafening.... new [Re: Otto Piechowski]
      #5433467 - 09/21/12 09:11 PM

Quote:

Oooooo! I can finally add something scientific.....

You two wrote, "I think that several years observing a putative Earth orbiting a Sun at that distance with big mirrors in interferometry mode (milliseconds arc resolution as mentioned above), could yield some 'compatible markers', like Oxygen, some greenish hint....We don't have any scopes that could resolve any of those things right now. And just seeing green won't mean anything - there are plenty of inorganic chemicals that can look green..."


A half century ago...possibly before you two were born...necessity required me at age 15 to make my own telescope...the whole thing...grind/polish/cut/mount/cast iron weights...two years later, I ended up with an 8 inch F8 Newtonian with 1/2 wavefront error...maybe even a whole wave error...it was so bad when I got it back from Clausing who coated it for me, they put in a note disclaiming responsibility for all the sleeks. Seems one is suppose to clean the former grinding slurry away before going to the next finest grade. (would be a quarter century later when I stopped it down to an F11 6 inch that I discovered I could see the Cassini division)....

anyway, I digress....I turned this behemoth at Mars one summer, and I saw GREEN. I saw a definitie gray-greens. I can only think of three reasonable explanations:
1. a contrast effect of the darker areas against the reddish area
2. there's green cholorophyll on Mars
3. there were so many sleeks on the mirror, it was prismatic

Compared to me....you are mere theoreticians. I did real science!

Otto




Dudley Leroy Clausing! Ah memories! Yes, clean up between grades of abrasive! Sam Brown!

-drl


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: The silence is deafening.... new [Re: deSitter]
      #5433485 - 09/21/12 09:23 PM

Yes, yes....Sam Brown...and what was that nearly unreadable red 3 volume mirror grinding set called?

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Jarad
Postmaster
*****

Reged: 04/28/03

Loc: Atlanta, GA
Re: The silence is deafening.... new [Re: dickbill]
      #5433590 - 09/21/12 10:50 PM

Quote:

There is not one theory, you are right, but many, BUT the thing is that they all converge toward a necessary autocatalytic molecular entity. Once this tipping point is reached, with autocatalytic molecular replicators trapped into oily vesicles, the transition from prebiotic to biotic is, i would say, not completely crazy.




No, not crazy at all. Just not fully understood, so we don't know all of the requirements. Therefore we can't say that because we don't see it on one or two planets that it's wrong - those planets may just be missing one or more of the unknown requirements.

Jarad


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llanitedave
Humble Megalomaniac
*****

Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: The silence is deafening.... new [Re: dickbill]
      #5433605 - 09/21/12 11:00 PM

Quote:

There is not one theory, you are right, but many, BUT the thing is that they all converge toward a necessary autocatalytic molecular entity. Once this tipping point is reached, with autocatalytic molecular replicators trapped into oily vesicles, the transition from prebiotic to biotic is, i would say, not completely crazy.

Just following wikipedia links, you' ll see the hypothesis of a pre-RNA world: the PAH-World, (Polycyclic Aromatic Hydrocarbon, believed to be abundant on early earth, and even in the martian meteorit ALH, if i recall) that would promote the pre-RNA world through the steps explained in http://en.wikipedia.org/wiki/PAH_world_hypothesis
A transient pre-RNA world would probably be short-lived, as it cannot compete well with the first really autocatalytic RNA forms.
http://en.wikipedia.org/wiki/RNA_world_hypothesis
So now the RNA/TNA/GNA-replicators World trapped with amino-acids inside lipid vesicle is considered as the critical step, and I guess we can call this assembly THE 'protocell'. The emphasis is not anymore how do we get to this protocell but how do we get to the TNA/GNA/RNA replicator. In addition to the PAH, a pre-rna Lipid World has also been proposed.




I agree 100%. Protocells, or at least the vesicles that house them, are easy, you can make them in your kitchen. Turning them into self-sustaining replicators, well that hasn't been done by humans as far as I know. It's that "critical step" that is probably a combination of many steps, steps that may require clay, or calcite, or ice, or evaporation, or acids, or bases, or some combination of several. It may require that the products of a clay reaction interact with products of an ice + evaporation reaction, or some other intricate chains of circumstance to assemble just the right molecules in just the right sequences.

We simply don't know at this point. Of course it's not crazy, it happened at least once. The question is, and will be for the forseeable future, in what set of natural environments can it happen again? And how broad or narrow are the circumstances that allow it?


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deSitter
Still in Old School


Reged: 12/09/04

Re: The silence is deafening.... new [Re: Jarad]
      #5433607 - 09/21/12 11:01 PM

Doesn't the actual ocean and atmospheric chemistry itself depend on a complex chain of events, just as unlikely as life? That is, there's iron and nickel in the water, but there are microbes that use nickel and emit methane, which however declines because a type of iron oxide scrubs the water of nickel and the microbes die, so now oxygen can accumulate in the atmosphere etc. etc. etc. - it's extremely complicated and specific. Can these events happen in a different order leading to the same result?

-drl


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llanitedave
Humble Megalomaniac
*****

Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: The silence is deafening.... new [Re: Otto Piechowski]
      #5433631 - 09/21/12 11:15 PM

Quote:

Three hours, and no response by you mere theoreticians to my sage comments about doing actual science with exquisite astronomical equipment?

Just for that….I will now add a word of philosophy. (“A word” of philosophy, Otto? That’ll be the day!)

The ancient Greek language was more flexible than English. For example, its common verbs each had between two hundred and three hundred forms whereas in English our verbs have between fifty and a hundred forms. This flexibility allowed the speakers of Greek to articulate issues with fine and helpful degrees of nuance, conducive to displaying truth.

This degree of nuance can be seen in how the Greek language handled two topics we are addressing here, life and theory (life, as in "extra-terrestrial life" and theory, as in "you mere theoreticians"). In fact, the Greek language connects the two concepts of life and theory in an interesting way.

Greek has two words for life, bios (pronounced “bee-ohss”) and zoa (pronounced “zoh-ay”). Zoa was used to refer to the word life in the sense we have been discussing it here; i.e. living things. Bios was often used to refer to the type of life a person lived. The difference, then, between these uses of zoa and bios was similar to the distinction we have in English between “life” and “a life” as in the trite phrase, “get a life”. Bios was often attached to other words such as politikos as in bios politikos (the active/public life) and, relevant to our second topic, theoretikos as in bios theoretikos (the thinking/contemplative life).




That's interesting, actually, although knowing the history of our current word meanings doesn't do anything to change those current meanings. And yes, it does appear at first glance as if modern English doesn't support the nuances of meaning and categorizing that ancient Greek did. It might also be the case, however, that some of those old categories were artificial and superfluous? Or that the terms that are passed down to us via scholarly works of the ancients were perhaps their own versions of specialized jargon, and not used in the same way by lay contemporaries? Or more likely, that English is just as expressive, but simply using different lexical and grammatical methods?

I tend to think that all human languages are capable of rich expressions of narrative, poetry, and even technical description if skillfully and flexibly used.

Quote:


But…I digress……




Hey, that's your second confessed digression in the same thread. I'll have to check to see if there's some sort of rule against that. (Or it may be a requirement, who knows?)

Quote:


...we, you and I, stargazers and scopists all, we who consider looking through a telescope for hours on end getting bitten by mosquitoes, getting frost bite on our toes, and/or going without sleep, to be having just a fine time...the rest of the non stargazing world is pretty sure we, you and I, do not have, bioi (pronounced bee-oy; the plural of bios). \





Just goes to show you that simply because one may have the vocabulary doesn't mean they have the understanding. This zooid wouldn't trade his bios with any of 'em.

Edited by llanitedave (09/22/12 01:19 AM)


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llanitedave
Humble Megalomaniac
*****

Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: The silence is deafening.... new [Re: deSitter]
      #5433651 - 09/21/12 11:30 PM

Quote:

Doesn't the actual ocean and atmospheric chemistry itself depend on a complex chain of events, just as unlikely as life? That is, there's iron and nickel in the water, but there are microbes that use nickel and emit methane, which however declines because a type of iron oxide scrubs the water of nickel and the microbes die, so now oxygen can accumulate in the atmosphere etc. etc. etc. - it's extremely complicated and specific. Can these events happen in a different order leading to the same result?

-drl




The thing about that interaction is that it's mediated by life. So it's unlikely only in the sense that it could never happen in the absence of biological influence, and it may well be historical happenstance that the particular set of relationships came about at all. Now that they exist, though, they're sustained by feedback mechanisms. Whether them happening in a different order would have led to the same result, or a different but still self-sustaining result, is a worthy question for exploration.

It's an interesting thing that there are several possible forms that photosynthesis can take, which do not result in free oxygen as a byproduct. Had some non-oxygen-producing photosynthesizer become dominant early on, it's quite possible that an ecosystem similar to the one we know might never have become possible.

Almost everything about life can be thought of as contingent, accidental, and extremely unlikely taken on its own. But what's even more mindblowing to me is that the range of possibilities is so high that even if none of the unlikely events that led to us occurred, there would have been other, equally unimaginably improbable events that happened in the alternative, that would have led to far different communities than the ones we know, but nevertheless just as diverse and rich as our own. And they might consider themselves the most natural and inevitable result of life's development.


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: The silence is deafening.... new [Re: llanitedave]
      #5433662 - 09/21/12 11:38 PM

That was very good, Dave! Ouch! Touche! Oh my!

About us thinking freezing our asses off is a hot time...I've had a bunch of psychological tests done on me over the years of all sorts...I would enjoy getting a whole bunch of stargazers and scopists together....maybe the entire crowd at a starparty like NEAF or stellafane...and do a good old fashioned MMPI on all of them and see if there are common neuroses. I think that would be interesting.


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: The silence is deafening.... new [Re: llanitedave]
      #5433664 - 09/21/12 11:40 PM

Dave...everyone....my memory is vague so help me/us with this....wasn't there a big to-do a few years back about somebody doing something very life like with.....what the hell was it....something like creating a totally artificial cell but transplanting a real nucleus into it.... or some such thing?

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deSitter
Still in Old School


Reged: 12/09/04

Re: The silence is deafening.... new [Re: Otto Piechowski]
      #5433673 - 09/21/12 11:42 PM

I have test anxiety. I was tested for it.

-drl


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: The silence is deafening.... [Re: deSitter]
      #5433701 - 09/22/12 12:09 AM

That was cute, drl.....I was giggling....and then, recalling how the soft-science people can be in trying to be hard-science-like....I don't doubt somebody actually might have done that....test for test taking anxiety. I seem to recall, drl, and others we were talking on another thread a couple weeks ago in which you remarked that soft-sciences try to ape the hard sciences so much, and I shared how this idea was found in Kuhn's book back in the 60s.

I don't know a whole lot more about psych than I do about science (the same old hand full of undergrad and grad courses and a stint as a therapist and pastoral minister type stuff)...but it seems to me that what these tests do is totally swallow the inductive method thing.

I can imagine, for example, someone saying, wouldn't it be good to be able to diagnose somebody as (I'm gong to make something up here) Larson-Infrarred-Inversion-Disorder (LIID) so that they we can label it as LIID according to the DSM4r so it can be filed for insurance payment. So let's devise a test, it can be answering 600 questions like the MMPI or draw a house/tree/person or an ink-blot session....it could be anything, give a person chinaware for a meal and see which utensil they pick up first...and then, gather 100 persons who you know to be LIID and give them the chinaware/utensil test, record which utensils they pick up in what order; develop a statistical model for prevalence-of-utensil-pickerupage. Let's say that 31% of the time we discover people with LIID pick up the fork, then the fork again, then the spoon and then the fork.

Next, someone comes into psychologist Jones' office with some unidentified disorder and he has the chinaware/utensil pickerupage test administered; he picks up a fork, then a fork, then a spoon, then a fork. Voila! He has LIID! It is recorded as LIID according to the description in the DSM4r, it is submitted to the insurance company and therapist Jones receives $175 from insurance with a $25 copay form the person identified as having LIID, and everybody is happy. Well, maybe not the insurance people. But probably they get a cut from the people who prepare, print, and evaluate the chinaware/utensil-pickerupper test.

I think I'm being facetious. Or full of scit. The neat thing about ancient languages is that sometimes a word in that langauge, which has its own meaning, has a pronuncation like a modern word in another language which means something totally different. So, for example, scit, which in Latin means "he/she/it knows", has a church Latin pronunciation identical to an unofficial English word for fecal matter.

So, is my facetious little diatribe on testing full of scit, or do you think I've hit a tack on the head with a 16 pound sledge hammer (i.e. overkill)?


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llanitedave
Humble Megalomaniac
*****

Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: The silence is deafening.... [Re: Otto Piechowski]
      #5433788 - 09/22/12 02:13 AM

Now folks, this remains a family site, so while we're talking about latin, let's be careful with the french.

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