>GM>It has been known for a while that non-racemic amino acids
>>existed in the Murchison meteorite.
>
>Yes. Originally it was claimed that since they were racemic it
>suggested the amino acids were extraterrestrial. Now they are
>thought to be non-racemic, it suggests they are terrestrial:
>
>"Added to this is the suggestive discovery of amino acids in
>meteorites, including some that are important in proteins. The
>Murchison meteorite, which fell in Australia in 1969, contained dl
>amino acids (More recent reports challenge this interpretation. See
>Michael H. Engel and Bartholomew Nagy, Nature 296, 1982, 837).
>including some proteinous ones. The presence of dl-amino acids was
>considered proof of extraterrestrial origin, and evidence that the
>meteorite was free of contamination from earth life. This is
>significant because the meteorite fell on a sheep farm, where
>remaining uncontaminated would be no trifling feat!" (Thaxton C.B.,
>Bradley W.L. & Olsen R.L., "The Mystery of Life's Origin:
>Reassessing Current Theories, Lewis & Stanley: Dallas TX, 1992,
>pp192-193)
>
The new report used an amino acid that does NOT appear in any terrestrial
living form and it was non-racemic and preferentially left-handed. Since
this particular amino acid is not incorporated into a earth species, it
cannot be contamination by terrestrial sources because no terrestrial
creatures use it.
>Glenn's "unknown to us at this moment" seems to indicate that he
>believes that this "mechanism" will become known to us in the future.
>I ask on what scientific evidence Glenn bases his belief on?
>
The FACT that a nonracemic, non-terrestrial form of amino acid was found in
a meteorite. If God himself made this then there is no mechanism. But I
don't think God did that.
>Croft further points out that one cannot ever be certain that the
>contents of a meteorite did not originate on earth:
>
>"At best one cannot be absolutely certain that, whatever one finds in
>a meteorite, it did not originate on the earth itself. Even if the
>meteorite were to have been collected soon after landing and if it
>had the minimum of handling, one can never be sure that it hadn't
>picked up biological material from a previous encounter with the
>earth. It is now known that some meteorites collide with the earth's
>atmosphere and are immediately ejected back into space, only to
>return many years later." (Croft L.R., 1988, p111)
You can be absolutely certain that the NON-TERRESTRIAL amino acid was not
picked up from earth life.
>
>Croft actually provides an alternative explanation for the amino
>acids in meteorites:
>
>"I believe there is a simple explanation for the presence of
>biochemicals in meteorites. They arise from contamination by pollen
>grains. Immense quantities of pollen are driven up into the upper
>atmosphere by air currents. During the descent of any meteorite the
>pollen grains become embedded into its surface cracks. Within the
>pollen shell are an abundance of amino acids. They are all of the L-
>type, but as the meteorite becomes hot, the amino acids racemize.
>Finally, as it passes through layers of cloud, water droplets wash
>out the amino acids from the pollen grains to leave a shell of
>sporopollenin....Proof of this suggestion comes from an inspection of
>the types of amino acid found in meteorites. They resemble very much
>the amino acids present in honey; take for example, pipecolic acid,
>a- amino butyric acid and b-alanine. These amino acids arise in
>honey from pollen. In fact the amino acids found in meteorites are
>characteristic of pollen. Pipecolic acid, for instance, is
>characteristic of grass pollen." (Croft L.R., 1988, p111)
The Science article uses none of the above mentioned amino acids so their
conclusion does not apply.
>
>Until Glenn does "know the mechanism" he cannot claim that "there is
>one". Apart from natural explanations given by Croft above, ie.
>previous encounter or ejection from the Earth, or contamination
>during descent, it is possible that God created first life elsewhere
>in the Solar System or even in another solar system. It is
>significant to me that Genesis 1 which deals with life on Earth only,
>does not say that God created the first life on Earth. This leaves
>open to me that God may have created life elsewhere and when Earth
>was ready caused it to be seeded with life from outside.
>
No, all that has to be shown is that a non-terrestial source created an
optically active amino acid not found in life. But as a matter of interest,
the authors of the Science article suggest that polarized light has had an
effect on the amino acid formation in the Murchison meteorite.
>See above. Even if it is shown that the L-amino acids were
>extraterrestrial, it still would not show that they were the result
>of a natural process unless that process is known. Science has tried
>every conceivable way to make L-amino acids naturally, but has drawn
>a complete blank.
This is not true. Using L-templates creates L forms. You can't say science
has drawn a complete blank.
>OK. But it should be remembered that this meteorite is "4.5 billion
>years" old, and it may be that these "amino acids" were once
>"found in terrestrial organisms" but have since become extinct.
>
What is your evidence for this? since we don't have ancient amino acids from
4.5 billion years ago, how do you know?
>GM>"By focussing on these particular amino acids, Cronin and
>>Pizzarello could avoid problems of contamination that would bias
>>the results. In each case, the researchers found an excess of the
>>left-handed form of the amino acid, ranging from 2 to 9 percent.
>>
>>"The findings indicate that even amino acids that are never found
>>in known life-forms, and so could not result from terrestrial
>>biological evolution, display a left-handed bias."~I. Peterson,
>>"Left-handed Excess in Meteorite Molecules", Science News, Feb 22,
>>1997, p. 118
>
>Interesting. If it was 50 or more "percent', I would find it
>more convincing.
It was as much as 59 percent left handed forms so why don't you find it
convincing, other than the fact that you don't want evolution to have any
evidence in its favor?
>Which in itself is a bit of a mystery. If there was a natural
>process in space that can bias amino acids acids towards
>L-handedness, one why would evidnece of it only be found "in the
>Murchison meteorite"? I would have thought that this suggests that
>the possibility of some unusual terrestrial contamination cannot be
>ruled out.
>
It isn't only found in the murchison meteorite, but this type of meteor, a
carbonaceous chondrite is a rare meteorite and only represents about 3
percent of all meteor falls. While rare, the Murchison is not alone.
"There is another small class of meteorites which we have not yet mentioned,
the carbonaceous chrondrites, which differ from the other classes and
consist mainly of the mineral serpentine[formula deleted]. They are
remarkable for the considerable amounts of organic compounds of
extraterrestrial origin that they contain and for the close correspondence
between their chemical composition and that of the Sun." Cambridge
Encyclopedia of Astronomy, 1977, p. 248
>GM>"The finding of enantiomeric excesses in amino acids indigenous
>>to the Murchison meteorite constitutes the first natural evidence
>>for the operation of an abiotic process for enantiomeric enrichment.
>
>I cannot see how they can draw this conclusion. It could equally be
>"evidence for the operation of a" *biotic* "process" on Earth or in
>space "4.5 billion years" ago.
>
>GM>The observations suggest that organic matter of extraterrestrial
>>origin could have played an essential role in the origin of
>>terrestrial life as a provider of the initial enantiomeric excesses
>>from which homochirality developed."~John R. Cronin and Sandra
>>Pizzarello, "Enantiomeric Excesses in Meteoritic Amino Acids,"
>>Science 275(February 14, 1997):951-955, p. 954
>
>Even granted all the above, this may still be something that the
>Intelligent Designer prepared and used. It is the planning,
>preparation and putting together that is the mark of Intelligent
>Design.
>
Nobody is denying this Stephen. I don't know why you think TEs on this list
are denying God's design.
glenn
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm