most researchers in the field refer to these compounds as "abiotic" or "prebiotic" compounds.
Sounds like they reached the same conclusion about confusing organic with living products ... not too surprising. Prebiotic works for me, being essentially the same derivation as my wording.
"Meteors" specifically refers to a body entering the Earth's atmosphere prior to landing.
Meteor\meteorite, again no biggie for me. The '-ites' have landed. Perhaps an effect of trying for layman ease and got a little loose.
Early models have assumed a "reducing" atmosphere ...
I intentionally changed this as most people wouldn't know that a reducing atmosphere was acidic by comparison. guilty. :D
... this line of evidence has been pretty much dismissed, ... However, this just pushes the origin back to 3.5 Ga, where we have less controversial evidence for life.
So much for that then. The 3.5 Ga data .... (google gooogle goooogle)
The oldest fossils are the approximately 3.465 Billion-year-old (Ga) microfossils from the Apex Chert, Australia. These are colonies of cyanobacteria (formerly called blue-green algae) which built real reefs.
Still archaea, link to thermophiles lessened, still need to have evolved somewhere ... ah sweet mystery of life eh?
Hi RAZD, looks great! Also, if you want another reference for the phosphorus work instead of Reddy 2004, you can cite: Pasek, M.A., and Lauretta, D.S., 2005, Astrobiology 5(4), 515-535. Let me know if you would like a copy of this article as a .pdf.
quote:The principle of the stability of chemical substance of the supramolecular structures of tissues makes it possible to understand the causes of the practically unlimited evolution of the biological world from the perspective of the Second Law in its classical definition. The full text of paper at: http://www.endeav.org/evolut/text/ta/ta.htm
quote: A number of available reviews relate to the Second Law and the origins and evolution of life. Some of them, however, contain a great deal of confusion. For instance, “Cosmic Ancestry†(http://www.panspermia.org/index.htm) in “The Second Law of Thermodynamics†contains quite a principled few mistakes. It would therefore appear to be extremely important to emphasize the need to use classical studies, especially where younger researchers are concerned. I will confine myself merely to the thermodynamic - the thermostatic theory of aging. The theory relies on hierarchical thermodynamics or macrothermodynamics (structural thermodynamics) which investigates quasi-closed systems over limited time frames. The fundamentals of the theory are spelt out in my book “Thermodynamic Theory of Evolution of Living Beingsâ€.
If I understand Dr. Georgi Gladyshev correctly classical science ALREADY contained a potential solution, right here on Earth. I also see no need to call in the seeds of change when one simply needs to wait for the other shoe to drop. Even if or when we find microbial life off of Earth the problem of tracking the trajectory through less limited time frames will continue to remain as it does today only we will have the extra burden of a loss of subjective morphological intuition we possess for creatures with Bauplanes more similar to ours. In this case, for instance Will Provine recently announced a conversation he had with Lyn Margulis in which Will came to the opinion that we might NEVER be able to construct a tree of life for the first few years on Earth and that he was OK with that. If there are microbes around the solarsystem and beyond we will be in the same position then as we are now with the need for a deductive biogeography. If classical science already provides the means to ends that do not need special pleading then I see no reason why they should not be used.
This website had contrasted “macroevolutionary progress†and a sorting out of preEarth ancestral area biogeography into post modern frames in mind paragonally. But if indeed macrothermodynamics has truth IN IT, then while there may indeed be some kind of “progress†that is often down played in most pedagogy on the structure of evolutionary theory today, there is NO such clear discrimination available TO THE CONTINUUM binding life reproductively (necessarily). The “solution†could be as simple as the expanded space origin hypothesizes but from the complexity of biodiversity already ON (Mother) Earth I see no a priori reason to suspect that empirics must give a solute other than those subject to hierarchical thermodynamics, in which class, the sorting must only be denoted to the primary parts rather than the total issue of genetic homogeneity in a whatever it is heterogenous crossing of Earth oribits over time.
'bump' brings old topics back into the current posting listings
I 'bump' a topic when someone is discussing a similar theme on another thread where it is off topic. In this case another questioning of abiogenesis 'probabilities' ...
quote:Stardust may be basis of life on Earth Alok Jha Friday December 15, 2006 Guardian Unlimited
Nasa launched Stardust to test the standard concept that comets are just dirty balls of snow left over from the early solar system. It was sent to examine the comet Wild 2 in February 1999.
The probe flew through the tail of dust and debris the comet had emitted and, after travelling 2.88bn miles, returned to Earth earlier this year with a payload of thousands of tiny particles from the comet.
To their surprise, scientists found a huge range of minerals in Wild 2. In particular, the samples showed evidence of aluminium- and calcium-rich minerals that could only have formed at very high temperatures, presumably close to the sun.
Wild 2 also seems to have some of the complex organic molecules that could be precursors to life.
"It's a fairly widely held belief that comets may have played a key role in delivering organics to the early Earth and played a role in getting life started," said Scott Sandford of Nasa's Ames research centre, who led one of the research teams.
When the Earth first formed, it would have been a molten body so hot that any organic materials already present on it would have perished. Any complex organic materials made in space would have had to arrive on the young Earth well after the planet had cooled down. "A lot of our findings support this interesting idea, which is that comets played this key role," said Dr Sandford.
"We don't know how life got started on the Earth. But one would presume that the more complex the things you drop on the Earth, the easier it might be for life to get started. We know that comets and asteroids deliver this sort of material."
Of most interest are the types of organic molecules seen in laboratory simulations of the early solar system, in which scientists irradiate ices containing dirt and dust. These produce a lot of organic compounds including amino acids; Wild 2 seems to contain similar molecules.
Dr Sandford said: "The possible presence of this material in the comet is exciting because it suggests that many [more] of these kinds of compounds that are biologically interesting may well be there."
"Every time it rains, it rains ... bennies from heaven ..."
Now I need to find a journal article that tells me what all those organic molecules were.
quote:Organic compounds contain carbon and hydrogen and form the building blocks of all life on Earth. By analyzing organic material and minerals in the Martian meteorite Allan Hills 84001, scientists at the Carnegie Institution's Geophysical Laboratory have shown for the first time that building blocks of life formed on Mars early in its history. Previously, scientists have thought that organic material in ALH 84001 was brought to Mars by meteorite impacts or more speculatively originated from ancient Martian microbes.
"Organic material occurs within tiny spheres of carbonate minerals in both the Martian and Earth rocks," explained Andrew Steele, lead author of the study. "We found that the organic material is closely associated with the iron oxide mineral magnetite, which is the key to understanding how these compounds formed."
quote:Comprehensive imaging and Raman spectroscopy of carbonate globules from Martian meteorite ALH 84001 and a terrestrial analogue from Svalbard A. STEELE, M. D. FRIES, H. E. F. AMUNDSEN, B. O. MYSEN, M. L. FOGEL, M. SCHWEIZER, and N. Z. BOCTOR
We report a comprehensive imaging study including confocal microRaman spectroscopy, scanning electron microscopy (SEM), and 3-D extended focal imaging light microscopy of carbonate globules throughout a depth profile of the Martian meteorite Allan Hills (ALH) 84001 and similar objects in mantle peridotite xenoliths from the Bockfjorden volcanic complex (BVC), Svalbard. Carbonate and iron oxide zoning in ALH 84001 is similar to that seen in BVC globules. Hematite appears to be present in all ALH 84001 carbonate-bearing assemblages except within a magnesite outer rim found in some globules. Macromolecular carbon (MMC) was found in intimate association with magnetite in both ALH 84001 and BVC carbonates. The MMC synthesis mechanism appears similar to established reactions within the Fe-C-O system. By inference to a terrestrial analogue of mantle origin (BVC), these results appear to represent the first measurements of the products of an abiotic MMC synthesis mechanism in Martian samples. Furthermore, the ubiquitous but heterogeneous distribution of hematite throughout carbonate globules in ALH 84001 may be partly responsible for some of the wide range in measured oxygen isotopes reported in previous studies. Using BVC carbonates as a suitable analogue, we postulate that a low temperature hydrothermal model of ALH 84001 globule formation is most likely, although alteration (decarbonation) of a subset of globules possibly occurred during a later impact event.
They don't say what the molecules are that they found.
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