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Ira
Carpal Tunnel
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Reged: 08/22/10

Loc: Mitzpe Ramon, Israel
Re: The silence is deafening.... new [Re: moynihan]
      #5428221 - 09/18/12 08:40 PM

An answer to this question is sheer speculation. Perhaps fun speculation; perhaps informative speculation, as it can teach us to look at things in different ways, but speculation nonetheless. Whenever anyone asks me if I believe in life elsewhere I always answer, It depends on what the last book was that I read.

/Ira
P.S. This was the last book I read on the subject, so now I am a disbeliever in life elsewhere (and not just intelligent life, either.)
http://www.amazon.com/Alone-Universe-Why-Planet-Unique/dp/1118147979/ref=sr_1_1?ie=UTF8&qid=1348018793&sr=8-1&keywords=we+are+alone


Edited by Ira (09/18/12 09:41 PM)


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scopethis
Postmaster
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Reged: 05/30/08

Loc: Kingman, Ks
Re: The silence is deafening.... new [Re: Ira]
      #5428268 - 09/18/12 09:05 PM

"How to Serve Mankind"

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moynihan
Carpal Tunnel


Reged: 07/22/03

Loc: Lake Michigan Watershed
Re: The silence is deafening.... new [Re: scopethis]
      #5428784 - 09/19/12 06:53 AM

Quote:

"How to Serve Mankind"






Good one


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Mister T
Pooh-Bah


Reged: 02/01/08

Loc: Upstate NY
Re: The silence is deafening.... new [Re: scopethis]
      #5430486 - 09/20/12 08:33 AM

They are not answering because that would cause mass hysteria and we taste better if we are not over-stressed.

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moynihan
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Reged: 07/22/03

Loc: Lake Michigan Watershed
Re: The silence is deafening.... new [Re: Mister T]
      #5430766 - 09/20/12 11:44 AM

For the pleasure of younger folk following this thread, the original episode from The Twilight Zone, "To Serve Man", 1962.

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MikeBOKC
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Reged: 05/10/10

Loc: Oklahoma City, OK
Re: The silence is deafening.... new [Re: moynihan]
      #5430797 - 09/20/12 12:02 PM

Current humanity, which focuses most of its SETI search on the radio spectrum even though more advanced civilizations may well have gone for beyond that technology for communication, are a lot like our Homo habilis ancestors squatting around a waterhole in Ouldavi gorge chipping away at flint nodules and wondering if anyone else lives over the next ridgeline, and if so how might they be contacted? The SETI questions will likely not be answered for 100, 1,000 or more years. It is simply too early to make any suppositions one way or another.

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scopethis
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Reged: 05/30/08

Loc: Kingman, Ks
Re: The silence is deafening.... new [Re: MikeBOKC]
      #5431266 - 09/20/12 04:23 PM

yep..and after 50,000 years humans just realized about 500-600 years ago that the planet was not flat...

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moynihan
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Reged: 07/22/03

Loc: Lake Michigan Watershed
Re: The silence is deafening.... new [Re: scopethis]
      #5431292 - 09/20/12 04:39 PM

Quote:

yep..and after 50,000 years humans just realized about 500-600 years ago that the planet was not flat...




Ancient greeks and egyptians figure that out actually,

But doing that is counter-intuitive, and quite an achievement.

To this day there are a number of important things that are counter-intuitive and counter - instinctual that we still have trouble accepting. Doing that ain't easy.


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simpleisbetter
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Reged: 04/18/11

Re: The silence is deafening.... new [Re: moynihan]
      #5431327 - 09/20/12 05:02 PM

There is written record dating as far back as 600-700BC of people accepting the Earth being a sphere, and Eratosthenes made a pretty accurate measurement of its size around 250-240BC. During Columbus' day many, maybe most, accepted the Earth was a sphere, they just thought the ocean was too vast to cross from W Europe to the Indies successfully. The whole "flat-earth" nonsense that's so frequently thrown around these days to claim we were ignorant until 500 yrs ago is no good.

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Kobayashi
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Reged: 07/10/08

Re: The silence is deafening.... new [Re: simpleisbetter]
      #5431900 - 09/20/12 11:23 PM

Quote:

During Columbus' day many, maybe most, accepted the Earth was a sphere, they just thought the ocean was too vast to cross from W Europe to the Indies successfully.




And they were right; Columbus was wrong when he thought he could travel to India directly by sailing west from Spain.


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scopethis
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Reged: 05/30/08

Loc: Kingman, Ks
Re: The silence is deafening.... new [Re: Kobayashi]
      #5431981 - 09/21/12 12:10 AM

knowing and speculating are different...just think of all the scientific speculating we had about the planet Venus before George Adamski went there...

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Kobayashi
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Reged: 07/10/08

Re: The silence is deafening.... new [Re: scopethis]
      #5432003 - 09/21/12 12:40 AM

As simpleisbetter said, the ancient Greeks not only knew the earth was a sphere, but also measured its size. Columbus' contemporaries knew this, and correctly criticized Columbus' proposal to sail west to India. More information here.

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Qwickdraw
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Reged: 03/03/12

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Re: The silence is deafening.... new [Re: MikeBOKC]
      #5432290 - 09/21/12 08:55 AM

Quote:

The SETI questions will likely not be answered for 100, 1,000 or more years. It is simply too early to make any suppositions one way or another.




I can realistically see somebody 1,000 years from now posting a similar comment on whatever form of social information networking is used at the time.


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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: The silence is deafening.... new [Re: Qwickdraw]
      #5432406 - 09/21/12 10:13 AM

It is absolutely NOT too early.
We now perfectly know the appropriate conditions, chemical and physical, for Life to occur and many chemical reactions that were still mysterious in the 70's have been identified. No steps are particularly improbable. In short, a computer program fed with these priors could simulate the event for an exoplanet.
To go back to the example I used before, it's like we now know that if we take an acid in acqueous solution, therefore in water liquid, and mix it with a base in the same conditions, then a reaction MUST occur. Then do it, If nothing happen then reconsider the theory of acid/base.
Similarly, the biggest and best known requisite for life is WATER, liquid. That's not the only one but it's the most stringent filter in the 'simulation' mentioned above.
So, IF and When an exoplanet with liquid water is discovered, and no signs of life are detected, you'd better prepare the arguments to save the current theory of life.
One failure might be OK, but the theory won't survive two.

The problem, as someone mentioned earlyer, is that there is no rush to study the best candidate exoplanets known so far (which is not Kepler 22, according to this site:
http://phl.upr.edu/projects/habitable-exoplanets-catalog )
But maybe it's because none of these exoplanets are really THE best possible case scenarios, and nobody wants to invest an entire observation campaign in something with less than 100% of success.
Can you publish "Spectral study of Gliese 581g doesn't reveal any markers compatible with biological activity" ?
Some observatory seems to be capable, but maybe they want the glory without the risks?

"...The main facility at Paranal is the VLT, which consists of four near-identical 8.2-metre Unit Telescopes (UTs), each hosting two or three instruments. These large telescopes can also work together, in groups of two or three, to form a giant 'interferometer', the ESO Very Large Telescope Interferometer or VLTI, allowing astronomers to see details up to 25 times finer than those seen with the individual telescopes. The light beams are combined in the VLTI using a complex system of mirrors located in underground tunnels where the light paths must be kept equal to distances less than 1/1000 mm over a hundred metres. With this kind of precision, the VLTI can achieve an angular resolution of milliarcseconds,..."
http://en.wikipedia.org/wiki/ESO


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Jarad
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Loc: Atlanta, GA
Re: The silence is deafening.... new [Re: dickbill]
      #5432434 - 09/21/12 10:31 AM

Quote:

In short, a computer program fed with these priors could simulate the event for an exoplanet.





No, it couldn't. We can't even properly simulate the folding of a single protein molecule using only the 20 amino acids found in life on earth.

Just finding water is nowhere near enough to prove that a planet could support life. It is certainly one of the requirements for life like us, but definitely not sufficient. Salts and organic molecules are certainly required, as well as a reasonable pH range (I doubt we will find life in extreme acid or base, although it can certainly tolerate some departure from pH 7), but we don't have good criteria yet for exactly what ranges of salt, pH, etc. can produce life.

There is also the aspect of time. The earth did not start out with life - it took a billion years or so. How do we know that a water-bearing planet just isn't "ripe" yet? Some people have postulated that the moon started out much closer to the earth, causing mega-tides which eroded rock and resulted in the oceans becoming salty, which may have been a critical step for life. What if the planet doesn't have a suitably large and close moon for that process?

And most importantly, as several people have pointed out, we couldn't detect life on earth from the distance of Alpha Centauri right now. So until we get sufficient technology to detect a lot more detail about exoplanets than we can now, we can't say that there isn't life there.

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: dickbill]
      #5432489 - 09/21/12 11:03 AM

Quote:


We now perfectly know the appropriate conditions, chemical and physical, for Life to occur and many chemical reactions that were still mysterious in the 70's have been identified. No steps are particularly improbable.




Not quite true. We know the conditions necessary for life to sustain itself. And that's a very broad range of conditions. What we don't know is all the conditions, steps, sequences, and events required for life to develop spontaneously from abiotic organic chemicals. And there's no indication that those steps allow for a broad range.

Water is certainly a necessary condition, but by no means sufficient. Protein chirality alone is a huge problem, and even though there are hints of progress on that one, it and many other issues are not yet resolved.


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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: The silence is deafening.... new [Re: Jarad]
      #5432508 - 09/21/12 11:15 AM

" We can't even properly simulate the folding of a single protein molecule using only the 20 amino acids found in life on earth.."

Jarad, not with a 100% certainty or accuracy, but models exist that can get you pretty close. 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. Conditions that depends on the orbital parameters can be estimated by observation, again with more or less accuracy. The age of planetary system/dust rings have been mentioned too, i donno how they do it though.
But yes, the presence of the Moon seemed, if not critical, at least a very important event in Life's history. IMO, the big tides it created acted more like a catalyser which means that in abscence of a (big) moon, prebiotic chemistry would occuur but on a much longer time scale.

I am puzzled by your statement that we could not detect 'life' at about 4-5 light years. 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.
That would not be definitve proof but that would encourage to build the only tool that can bring the final verdict:
Space Interferometer with very long base, nulling and all the hoopla.


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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: The silence is deafening.... new [Re: dickbill]
      #5432543 - 09/21/12 11:39 AM

Ilanitedave, yes, we don't know all the details. I could evade the problem like evolutionarist do: 'with enough time...'.
How can we reproduce in laboratory reactions that, when combined, start to look like prebiotic chemistry only after a million years?


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llanitedave
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Reged: 09/26/05

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Re: The silence is deafening.... [Re: dickbill]
      #5432573 - 09/21/12 11:59 AM

No you can't evade it with time. We aren't talking about biological evolution, we're talking about the origin of life. They are two different sets of processes, with two different dynamics. That's one of the biggest reasons people mislead themselves on this topic, by conflating the two.

There's no known necessary requirement for long time periods for the origin of life. It might be required, it might not. We don't know. As for the combining of laboratory reactions, that's the other problem. We don't know what laboratory reactions to apply, regardless of the amount of time involved. We know some of the basic steps, but the details of those steps we do know, and other entire steps that are just as basic, are still not settled.

And that is coming from an optimist.


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Otto Piechowski
Pooh-Bah


Reged: 09/20/05

Loc: Lexington, KY
Re: The silence is deafening.... [Re: llanitedave]
      #5432653 - 09/21/12 12:49 PM

The idea you just articulated, Dave...it is as if it has been in my head for ages, but your clear articulation just made the issue...the n=1 issue so very clear to me. Though we understand some of the conditions under which evolution occurs, we cannot say we know the conditions under which the origin of life occurs.

Otto


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