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How did life begin on Earth?

 
 
Acquiunk
 
  1  
Reply Thu 16 Dec, 2004 08:25 am
Bi-Polar Bear wrote:
rocks ....ther were rocks...and God spoke and the rocks formed giant rock groups....



I suppose that those from the earth's core were heavy metal
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blueveinedthrobber
 
  1  
Reply Thu 16 Dec, 2004 08:39 am
Acquiunk wrote:
Bi-Polar Bear wrote:
rocks ....ther were rocks...and God spoke and the rocks formed giant rock groups....



I suppose that those from the earth's core were heavy metal


very asute...very intuitive...and of course...absolutey correct.... :wink:
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rosborne979
 
  1  
Reply Thu 16 Dec, 2004 09:05 am
Adrian wrote:
rosborne979 wrote:
Einherjar wrote:
Spacedust, remnants of a supernova. Heated I presume by gravitational compression.


Correct. Geothermal energy is primarily a result of gravitational compression. There are also tidal forces from orbital systems (particularly the Moon), and the heat from the Earth's core is at least partially due to nuclear reactions (I think it's a for of heat induced decay, but I would have to look that up).


The heat is MOSTLY due to the radioactive decay of uranium, thorium and, it was recently found, potassium. The remnant heat left over from accretion is still there but it's only about 20% of the total.


Aren't the radioactive decay processes you mentioned dependent on high pressures (ultimately from gravity) though?
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Adrian
 
  1  
Reply Thu 16 Dec, 2004 05:45 pm
Not that I know of. It's just standard decay of the naturally occuring radioactive isotopes. There used to be a problem in that there didn't seem to be enough uranium and thorium to produce the heat we've got, but it was found that at high temperature and pressure potassium and iron form an alloy. The potassium brings the models in line with the observations.
The potassium component is fading the quickest because it's half life is only about 1.5 billion years. Uranium and thorium last WAY longer than that.
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rosborne979
 
  1  
Reply Thu 16 Dec, 2004 06:44 pm
Adrian wrote:
... but it was found that at high temperature and pressure potassium and iron form an alloy...


Ok, so I guess some of the decay process is affected by heat/pressure from gravity, but most of the heat is a result of simple decay.
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Adrian
 
  1  
Reply Thu 16 Dec, 2004 07:13 pm
The haet/pressure doesn't really cause the decay, it's just that the only way potassium would end up in the core is if there was, in the past, enough heat/pressure to make the potassium mix with the iron which eventually became the core.

Click for more.
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rosborne979
 
  1  
Reply Wed 16 Nov, 2005 09:26 pm
Adrian wrote:
The haet/pressure doesn't really cause the decay, it's just that the only way potassium would end up in the core is if there was, in the past, enough heat/pressure to make the potassium mix with the iron which eventually became the core.

Click for more.


Interesting. I stand corrected.
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rosborne979
 
  1  
Reply Fri 18 Jan, 2008 05:16 pm
Now... where were we?
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fresco
 
  1  
Reply Fri 18 Jan, 2008 10:10 pm
...continuity being the antithesis of "time passing"... Smile

Note (from the ontology thread) that the phrase "origins of" implies a causal explanation involving "linear time", but that such questions may be an epiphenomenon of life/cognition proesses and therefore not applicable to the process itself. (Piaget/Capra/Maturana).
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rosborne979
 
  1  
Reply Fri 18 Jan, 2008 11:55 pm
fresco wrote:
...continuity being the antithesis of "time passing"... Smile

Note (from the ontology thread) that the phrase "origins of" implies a causal explanation involving "linear time", but that such questions may be an epiphenomenon of life/cognition proesses and therefore not applicable to the process itself. (Piaget/Capra/Maturana).

Or, reality could be real, just as it appears to be.
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fresco
 
  1  
Reply Sat 19 Jan, 2008 02:08 am
Rosborne,

If we were living 500 years ago, what would have been the nature of "reality" ? And now we have proxy "living" in cyberspace, genetic engineering, nonlocality etc...what will be the nature of "reality" 500 years hence ?

The argument that "reality" is independent of "us" seems intellectually vacuous.
0 Replies
 
Chumly
 
  1  
Reply Sat 19 Jan, 2008 02:44 am
I voted for "ET intelligence placed replicative molecules on Earth intentionally" because it amuses me and I like the romanticism it implies, but there is no direct reason to expect this to be more plausible than "Evolutionary forces affecting raw materials led to replicative molecules and life".

As far as "Pre-existing replicative molecules arrived on asteroids" there is nothing (in principle at least) to stop this from being a source just as there is nothing to stop "Evolutionary forces affecting raw materials led to replicative molecules and life" from being a source.
0 Replies
 
farmerman
 
  1  
Reply Sat 19 Jan, 2008 03:52 am
Never one for too much respect for arcane terms, I nevertheless am in favor of JD Bernals simple term "Biopoesis" rather than "abiogenesis of dissipative structures." The former isnt a pompous mouthful, and the latter just takes way too much time to say. Laughing

Bernal got his chops from being a pioneer in X-ray crystal photography of life pattern crystals (proteins etc) > He gave Ros Franklin the tools with which to break the DNA code (for which Watson and Crick, mostly by outliving her, got a Nobel prize).
The work of Rasmussen and VEnter (separate teams in separate areas ) has provided us with closer and closer reconstruction on the Abiogenesis (day1 and ground zero).

Rasmussen has been working on the standard "bottoms up" model of building the "living state" molecule by using the phospholipid-to lipid bilayer-to formation of tRNA segments via ribozymal peptide linkage. All the feedstock input thats needed, besides a "chemical soup and energy" is a hyfraulic model that feeds water through the system at fairly high volumes while still retaining laminar flow. The best "neighborhood" for the formation by RAsmussens method is the clay deposits (bi-layers of phylosilicates) that occur around high energy suboceanic vents. "Smokers". Fancy that, weve got a planetary slow cooker thats been in existence for at least as long as the planets had water.


Venter's approach has been somewhat more "lazy man" as is his brilliant MO(I think that Venter is the true genius because of his "scientists are lazy" approach to problem solving). Hes had his guys take existing prokaryotic cells and has been REMOVING protein segments until the living state no longer exists.

However, for Creation purposes, I do like the bottom up method because it may be more prokaryote inclusive. ALthough we base our life model on a CArbon/Phosphorus base, RAsmussen has always spoken about transitional life forms that were CArbon-Arsenic, or CArbon-Silica, or Carbon Iron base. These living state models could have been merely transitional and ephemeral but could have developed the simplest tRNA molecule that would have remained stable in a "dissipative environment"

I follow up with Los Alamos on this periodically and the importance of hydraulics has been recently modeled using it as a force in the overall reactions. Noone still knows , although we get closer and closer and there are now predictions when either Rasmussen , or VEnter will unlock the key.
0 Replies
 
rosborne979
 
  1  
Reply Sun 22 Jun, 2008 10:02 am
Some interesting video lectures on the subject
0 Replies
 
 

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