another debunking required
lodger
somebody please take a point-by-point analysis of this blurb and do
any debunking required for me? Especially the points related to Del
Mar man and the Sunnyvale skeleton in regards to Amino-Acid
Racemization.
Thanks in advance, you guys rock,
Lodger
"Errors in the Radiocarbon Clock
The radiocarbon clock looked very simple and straightforward when it
was first demonstrated, but it is now known to be prone to many kinds
of error. After some 20 years' use of the method, a conference on
radiocarbon chronology and other related methods of dating was held in
Uppsala, Sweden, in 1969. The discussions there between chemists who
practice the method and archaeologists and geologists who use the
results brought to light a dozen flaws that might invalidate the
dates. In the 17 years since then, little has been accomplished to
remedy these shortcomings.
One nagging problem has always been to ensure that the sample tested
has not been contaminated, either with modern (live) carbon or with
ancient (dead) carbon. A bit of wood, for example, from the heart of
an old tree might contain live sap. Or if that has been extracted with
an organic solvent (made from dead petroleum), a trace of the solvent
might be left in the portion analyzed. Old buried charcoal might be
penetrated by rootlets from living plants. Or it might be contaminated
with much older bitumen, difficult to remove. Live shellfish have been
found with carbonate from minerals long buried or from seawater
upwelling from the deep ocean where it had been for thousands of
years. Such things can make a specimen appear either older or younger
than it really is.
The most serious fault in radiocarbon-dating theory is in the
assumption that the level of carbon 14 in the atmosphere has always
been the same as it is now. That level depends, in the first instance,
on the rate at which it is produced by cosmic rays. Cosmic rays vary
greatly in intensity at times, being largely affected by changes in
the earth's magnetic field. Magnetic storms on the sun sometimes
increase the cosmic rays a thousandfold for a few hours. The earth's
magnetic field has been both stronger and weaker in past millenniums.
And since the explosion of nuclear bombs, the worldwide level of
carbon 14 has increased substantially.
On the other hand, the proportion is affected by the quantity of
stable carbon in the air. Great volcanic eruptions add measurably to
the stable carbon-dioxide reservoir, thus diluting the radiocarbon. In
the past century, man's burning of fossil fuels, especially coal and
oil, at an unprecedented rate has permanently increased the quantity
of atmospheric carbon dioxide. (More details on these and other
uncertainties in the carbon-14 clock were given in the April 8, 1972,
issue of Awake!)
Dendrochronology-Dating by the Growth Rings of Trees
Faced with all these fundamental weaknesses, the radiocarbon people
have turned to standardizing their dates with the help of wood samples
dated by counting tree rings, notably those of bristlecone pines,
which live hundreds and even thousands of years in the southwestern
United States. This field of study is called dendrochronology.
So the radiocarbon clock is no longer regarded as yielding an absolute
chronology but one which measures only relative dates. To get the true
date, the radiocarbon date has to be corrected by the tree-ring
chronology. Accordingly, the result of a measurement of radiocarbon is
referred to as a "radiocarbon date." By referring this to a
calibration curve based on tree rings, the absolute date is inferred.
This is sound for as far back as the bristlecone ring count is
reliable. The problem now comes up that the oldest living tree whose
age is known goes back only to 800 C.E. In order to extend the scale,
scientists try to match overlapping patterns of thin and thick rings
in pieces of dead wood found lying nearby. By patching together 17
remnants of fallen trees, they claim to go back over 7,000 years.
But the tree-ring standard does not stand alone either. Sometimes they
are not sure just where to put one of the dead pieces, so what do they
do? They ask for a radiocarbon measurement on it and use that as a
guide in fitting it in. It reminds one of two lame men with only one
crutch between them, who take turns using it, one leaning for a while
on his partner, then helping to hold him up.
One must wonder at the miraculous preservation of loose bits of wood
lying so long in the open. It would seem they might have been washed
away by heavy rainfall or picked up by passersby for firewood or some
other use. What has prevented rot or insect attack? It is credible
that a living tree might withstand the ravages of time and weather, an
occasional one surviving for a thousand years or more. But dead wood?
For six thousand years? It strains credibility. Yet this is what the
older radiocarbon dates are based on.
Nevertheless, the radiocarbon experts and the dendrochronologists have
managed to put aside such doubts and smooth over the gaps and
inconsistencies, and both feel satisfied with their compromise. But
how about their customers, the archaeologists? They are not always
happy with the dates they get back on the samples they send in. One
expressed himself this way at the Uppsala conference:
"If a carbon-14 date supports our theories, we put it in the main
text. If it does not entirely contradict them, we put it in a
footnote. And if it is completely 'out of date,' we just drop it."
Some of them still feel that way. One wrote recently concerning a
radiocarbon date that was supposed to mark the earliest domestication
of animals:
"Archeologists [are coming] to have second thoughts about the
immediate usefulness of radiocarbon age determinations simply because
they come out of 'scientific' laboratories. The more that confusion
mounts in regard to which method, which laboratory, which half-life
value, and which calibration is most reliable, the less we
archeologists will feel slavishly bound to accept any 'date' offered
to us without question."
The radiochemist who had supplied the date retorted: "We prefer to
deal with facts based on sound measurements-not with fashionable nor
emotional archeology."
If scientists disagree so sharply about the validity of these dates
reaching back into man's antiquity, is it not understandable that
laymen might be skeptical about news reports based on scientific
"authority," such as those quoted at the head of this series of
articles?
Direct Counting of Carbon 14
A recent development in radiocarbon dating is a method for counting
not just the beta rays from the atoms that decay but all the carbon-14
atoms in a small sample. This is particularly useful in dating very
old specimens in which only a tiny fraction of the carbon 14 is left.
Out of a million carbon-14 atoms, only one, on the average, will decay
every three days. This makes it quite tedious, when measuring old
samples, to accumulate enough counts to distinguish the radioactivity
from the cosmic-ray background.
But if we can count all the carbon-14 atoms now, without waiting for
them to decay, we can gain a millionfold in sensitivity. This is
accomplished by bending a beam of positively charged carbon atoms in a
magnetic field to separate the carbon 14 from the carbon 12. The
lighter carbon 12 is forced into a tighter circle, and the heavier
carbon 14 is admitted through a slit into a counter.
This method, although more complicated and more expensive than the
beta-ray-counting method, has the advantage that the amount of
material needed for a test is a thousand times less. It opens up the
possibility of dating rare ancient manuscripts and other artifacts
from which a sample of several grams that would be destroyed in
testing just cannot be had. Now such articles can be dated with just
milligrams of sample.
One suggested application of this would be to date the Shroud of
Turin, which some believe Jesus' body was wrapped in for burial. If
radiocarbon dating was to show that the cloth is not that old, it
would confirm the suspicions of doubters that the shroud is a hoax.
Until now, the archbishop of Turin has refused to donate a sample for
dating because it would take too large a piece. But with the new
method, one square centimeter would be enough to determine whether the
material dates from the time of Christ or only from the Middle Ages.
In any event, attempts to extend the time range have little
significance as long as the greater problems remain unsolved. The
older the sample is, the more difficult it is to ensure the complete
absence of slight traces of younger carbon. And the farther we try to
go beyond the few thousand years for which we have a reliable
calibration, the less we know about the atmospheric level of carbon 14
in those ancient times.
Several other methods have been studied for dating events in the past.
Some of these are related indirectly to radioactivity, such as the
measurement of fission tracks and radioactive halos. Some involve
other processes, such as the deposition of varves (layers of sediment)
by streams flowing from a glacier and the hydration of obsidian
artifacts.
Amino-Acid Racemization
The racemization of amino acids is another dating method used. But
what does "racemization" mean?
Amino acids belong to the group of carbon compounds that have four
different groups of atoms attached to a central carbon atom. The
tetrahedral arrangement of the groups makes the molecule asymmetrical
as a whole. Such molecules exist in two forms. Although chemically
identical, one is physically the mirror image of the other. A simple
illustration of this is a pair of gloves. They have the same size and
shape, but one fits only your right hand, the other only your left.
A solution of one form of such a compound twists a beam of polarized
light to the left; the other kind rotates it to the right. When a
chemist synthesizes an amino acid from simpler compounds, he gets
equal amounts of both forms. Each form cancels out the effect of the
other on polarized light. This is called a racemic mixture, when both
left-handed and right-handed amino acids are equally present in the
mixture.
When amino-acid compounds are formed in living plants or animals, they
come in only one form, usually the left-handed, or l- (for levo-)
form. If such a compound is heated, the thermal agitation of the
molecules turns some of them inside out, changing the left-handed form
to the right-handed (the dextro form). This change is called
racemization. Continued long enough, it produces equal amounts of the
l- and d-forms. It is of special interest because it relates to living
things, as does radiocarbon dating.
At lower temperatures, racemization goes at a slower pace. How much
slower depends on the energy it takes to invert the molecule. It
follows a well-known chemical law, known as the Arrhenius equation. If
the amino acid is cooled more and more, the reaction goes slower and
slower until, at ordinary temperatures, we cannot see it changing at
all. But we can still use the equation to calculate how fast it is
changing. It turns out that it would take tens of thousands of years
for a typical amino acid to approach the racemized state, when both
left-handed and right-handed forms of the amino acids are present in
equal quantities.
The idea for dating by this method is this: If a bone, for example, is
buried and left undisturbed, the aspartic acid (a crystallized amino
acid) in the bone is slowly racemized. We dig up the bone a long time
later, extract and purify the remaining aspartic acid, and compare its
degree of polarization with that of pure l-aspartic acid. Thus we can
estimate how long ago the bone was part of a living creature.
The decay curve is similar to that of a radioactive element. Each
amino acid has its own characteristic rate of decay, just as uranium
decays slower than potassium. However, note this important difference:
Radioactive rates are unaffected by temperature, whereas racemization,
being a chemical reaction, is markedly dependent on temperature.
Some of the most highly publicized applications of the racemization
method have been to human skeletal remains found along the coast of
California. One, called the Del Mar man, was dated by this method at
48,000 years. Another, the skeleton of a female found in an excavation
near Sunnyvale, appeared to be even older, a startling 70,000 years!
These ages created quite a stir not only in the public press but
especially among paleontologists, because no one had believed that man
was in North America that long ago. Speculation arose that man could
have wandered across the Bering Strait from Asia as much as a hundred
thousand years ago. But how certain were the dates turned out by this
novel method?
To answer this, tests were made by a radioactive method involving
intermediate decay products between uranium and lead that have
half-lives suitable for this range. This gave ages of 11,000 years for
the Del Mar skeleton and only 8,000 or 9,000 for the Sunnyvale.
Something was wrong.
The big uncertainty in racemization ages is the unknown thermal
history of the specimen. As mentioned above, the rate of racemization
is extremely sensitive to temperature. If the temperature goes up by
25 degrees Fahrenheit (14° C), the reaction goes ten times as fast.
How could anyone know what temperatures the bones could have been
exposed to so many years in the past? How many summers might they have
lain bare under a hot California sun? Or might they even have been in
a campfire or a forest fire? Besides the temperature, other factors
have been found to affect the rate greatly, such as the pH (degree of
acidity). One report says: "Amino acids in sediments show an initial
rate of racemization almost an order of magnitude (tenfold) faster
than the rate observed for free amino acids at a comparable pH and
temperature."
Even that is not the end of the story. One of the Sunnyvale bones was
tested for radiocarbon, both by the counting of beta particles from
decaying atoms and by the newer atom-counting method. These gave
roughly concordant values. The average was only 4,400 years!
What can we believe? Obviously some of the answers are terribly wrong.
Should we put more confidence in the radiocarbon date, since there is
longer experience in using it? But even with it, different samples
from the same bone varied from 3,600 to 4,800 years. Perhaps we should
just admit, in the words of the scientist quoted previously, "Maybe
all of them are wrong.""
eNo
> What can we believe?
Well, we can believe that C14 dating is prone to some gotchas and
perhaps requires independent verification (i.e., calibration) and
certainly care to not contaminate samples with carbon-based substances.
Here's one place to start looking:
http://www.talkorigins.org/indexcc/CD/CD011_1.html
--
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eNo
"If you can't go fast, go long."
øĪš°`°šĪø,,,,øĪš°`°šĪø,,,,øĪš°`°šĪø,,,,øĪš°`°šĪøĪš°`°šĪø,,,,øĪš
Harlequin
news:4b9cfdb7.04042...@posting.google.com:
[snip]
> The most serious fault in radiocarbon-dating theory is in the
> assumption that the level of carbon 14 in the atmosphere has always
> been the same as it is now.
This is not true. While one can do naive applictions like that,
today the method calibrated using samples of known age.
> That level depends, in the first instance,
> on the rate at which it is produced by cosmic rays. Cosmic rays vary
> greatly in intensity at times, being largely affected by changes in
> the earth's magnetic field. Magnetic storms on the sun sometimes
> increase the cosmic rays a thousandfold for a few hours. The earth's
> magnetic field has been both stronger and weaker in past millenniums.
Which is why the calibration is done.
> And since the explosion of nuclear bombs, the worldwide level of
> carbon 14 has increased substantially.
[snip]
This one is simply irrelevent unless you are carbon dating an item
younger than the first nuclear explosions.
I will also point out that the age of the Earth does not depend
on radiocarbon which is only used for EXTREMELY young organic
remains (of certain types).
A bit of advice: You might make the the subject line of a thread
like this "Radiocarbon: Another debunking required".
--
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Tired of creationist political victories undermining science education?
Sign up for low-volume moderated email updates on creationist
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eNo
its own set of gotchas. Can anyone confirm this, and/or detail methods
developed to aleviate the problem described below?
"To determine the extent of correction necessary to render the
radiocarbon method reliable, dendrochronologists devised a plan to
control the radiocarbon dates by building a chronology of tree rings of
the white bristlecone pine, the longest living tree. The method caught
the fancy of the radiocarbon researchers. However, three or four rings
formed in one year is not uncommon, especially if the tree grows on a
slope, with the ground several times in a year turning wet and dry
because of rapid outflow of water (Glueck et al., Botanical Review, 7,
649-713; and 21, 245-365). And certainly the building of tree 'ladders,'
or carrying on the count from one tree to another may cause erroneous
conclusions. One and the same year may be dry in South California and
wet in the northern part of the state."
http://www.varchive.org/ce/c14.htm
John Harshman
lodger wrote:
All true. Of course, these can all be fixed by careful selection and
treatment of the samples.
> The most serious fault in radiocarbon-dating theory is in the
> assumption that the level of carbon 14 in the atmosphere has always
> been the same as it is now. That level depends, in the first instance,
> on the rate at which it is produced by cosmic rays. Cosmic rays vary
> greatly in intensity at times, being largely affected by changes in
> the earth's magnetic field. Magnetic storms on the sun sometimes
> increase the cosmic rays a thousandfold for a few hours. The earth's
> magnetic field has been both stronger and weaker in past millenniums.
> And since the explosion of nuclear bombs, the worldwide level of
> carbon 14 has increased substantially.
>
> On the other hand, the proportion is affected by the quantity of
> stable carbon in the air. Great volcanic eruptions add measurably to
> the stable carbon-dioxide reservoir, thus diluting the radiocarbon. In
> the past century, man's burning of fossil fuels, especially coal and
> oil, at an unprecedented rate has permanently increased the quantity
> of atmospheric carbon dioxide. (More details on these and other
> uncertainties in the carbon-14 clock were given in the April 8, 1972,
> issue of Awake!)
All true. Mind you, the differences are not particularly big. We're
talking about a few percent, not the orders of magnitude necessary to
fit the creationist timetable.
> Dendrochronology-Dating by the Growth Rings of Trees
>
> Faced with all these fundamental weaknesses, the radiocarbon people
> have turned to standardizing their dates with the help of wood samples
> dated by counting tree rings, notably those of bristlecone pines,
> which live hundreds and even thousands of years in the southwestern
> United States. This field of study is called dendrochronology.
>
> So the radiocarbon clock is no longer regarded as yielding an absolute
> chronology but one which measures only relative dates. To get the true
> date, the radiocarbon date has to be corrected by the tree-ring
> chronology. Accordingly, the result of a measurement of radiocarbon is
> referred to as a "radiocarbon date." By referring this to a
> calibration curve based on tree rings, the absolute date is inferred.
>
> This is sound for as far back as the bristlecone ring count is
> reliable. The problem now comes up that the oldest living tree whose
> age is known goes back only to 800 C.E. In order to extend the scale,
> scientists try to match overlapping patterns of thin and thick rings
> in pieces of dead wood found lying nearby. By patching together 17
> remnants of fallen trees, they claim to go back over 7,000 years.
>
> But the tree-ring standard does not stand alone either. Sometimes they
> are not sure just where to put one of the dead pieces, so what do they
> do? They ask for a radiocarbon measurement on it and use that as a
> guide in fitting it in. It reminds one of two lame men with only one
> crutch between them, who take turns using it, one leaning for a while
> on his partner, then helping to hold him up.
Works, though. Because the differences between the calibrated and
uncalibrated datings are only a few percent, you can get into the right
ballpark with uncalibrated dates.
> One must wonder at the miraculous preservation of loose bits of wood
> lying so long in the open. It would seem they might have been washed
> away by heavy rainfall or picked up by passersby for firewood or some
> other use. What has prevented rot or insect attack? It is credible
> that a living tree might withstand the ravages of time and weather, an
> occasional one surviving for a thousand years or more. But dead wood?
> For six thousand years? It strains credibility. Yet this is what the
> older radiocarbon dates are based on.
Simply: the wood was buried, and recently uncovered by erosion. This is
the same way all fossils are preserved. Did that revelation really
escape the writer?
> Nevertheless, the radiocarbon experts and the dendrochronologists have
> managed to put aside such doubts and smooth over the gaps and
> inconsistencies, and both feel satisfied with their compromise. But
> how about their customers, the archaeologists? They are not always
> happy with the dates they get back on the samples they send in. One
> expressed himself this way at the Uppsala conference:
>
> "If a carbon-14 date supports our theories, we put it in the main
> text. If it does not entirely contradict them, we put it in a
> footnote. And if it is completely 'out of date,' we just drop it."
I'd like to see the reference for this.
> Some of them still feel that way. One wrote recently concerning a
> radiocarbon date that was supposed to mark the earliest domestication
> of animals:
>
> "Archeologists [are coming] to have second thoughts about the
> immediate usefulness of radiocarbon age determinations simply because
> they come out of 'scientific' laboratories. The more that confusion
> mounts in regard to which method, which laboratory, which half-life
> value, and which calibration is most reliable, the less we
> archeologists will feel slavishly bound to accept any 'date' offered
> to us without question."
This one too. "Half-life value"? Since when is the half-life of any
radionuclide vulnerable to serious measurement error?
Must be an old article. This was actually done. Surprise, the date was
much younger than the first century AD.
Note that the error in even these methods is "only" 25%, not close to
good enough to make the flood scenario work. Further, the flood requires
that all the other dating methods they didn't mention not work too, not
just the ones that work for recent (<100Ky) samples, but the ones that
work for stuff that's millions or billions of years old. If most
sediments are flood sediments, why do all the various radiometric dating
methods give them dates ranging from >4by all the way through the
present? To make the flood work, that would require an error value of a
hundred million percent! You need to pile up a lot of quibbles to reach
that high.
rossum
wrote:
>The following is from an Awake! magazine published in 1986. Can
>somebody please take a point-by-point analysis of this blurb and do
>any debunking required for me? Especially the points related to Del
>Mar man and the Sunnyvale skeleton in regards to Amino-Acid
>Racemization.
>
>Thanks in advance, you guys rock,
>
>Lodger
>
>"Errors in the Radiocarbon Clock
>
For a good introduction to Radiometric dating see Richard Weins piece
on the ASA site: http://www.asa3.org/ASA/resources/Wiens.html
(Yes it is the same one I referenced in response to your other
debunking request.
>The radiocarbon clock looked very simple and straightforward when it
>was first demonstrated, but it is now known to be prone to many kinds
>of error. After some 20 years' use of the method, a conference on
>radiocarbon chronology and other related methods of dating was held in
>Uppsala, Sweden, in 1969. The discussions there between chemists who
>practice the method and archaeologists and geologists who use the
>results brought to light a dozen flaws that might invalidate the
>dates. In the 17 years since then, little has been accomplished to
>remedy these shortcomings.
And a lot has been done since then.
>
>One nagging problem has always been to ensure that the sample tested
>has not been contaminated, either with modern (live) carbon or with
>ancient (dead) carbon. A bit of wood, for example, from the heart of
>an old tree might contain live sap. Or if that has been extracted with
>an organic solvent (made from dead petroleum), a trace of the solvent
>might be left in the portion analyzed. Old buried charcoal might be
>penetrated by rootlets from living plants. Or it might be contaminated
>with much older bitumen, difficult to remove.
A known problem, which scientists go to a lot of trouble to avoid.
For a start there are plenty on non-organic solvents (starting with
water) which will not have any effect on Carbon dating.
>Live shellfish have been
>found with carbonate from minerals long buried or from seawater
>upwelling from the deep ocean where it had been for thousands of
>years. Such things can make a specimen appear either older or younger
>than it really is.
Any marine specimen has a big red flag on it saying "Do not Carbon
date this" for just that reason. There are a few results from marine
samples from the early days of Carbon dating which were done precisely
in order to measure this effect. Scientists wanted to check if the
"old Carbon" effect was big enough to make a difference. It was so
now C14 isn't used on marine samples.
>
>The most serious fault in radiocarbon-dating theory is in the
>assumption that the level of carbon 14 in the atmosphere has always
>been the same as it is now.
Scientists make no such assumption. They are aware that the level of
C14 in the atmosphere has varied over time so the go out and do
experiments to measure the effect.
1 Find something with a known date (e.g. wood from Pompeii)
2 Carbon date it.
3 Work out the discrepancy between the actual date and the C14 date.
4 Repeat and build a chart of the discrepancies.
5 Use the chart to correct the discrepancy in a C14 date for an object
of unknown date.
There is just such a correction chart on p14 of Roger Weins piece I
linked to above.
>That level depends, in the first instance,
>on the rate at which it is produced by cosmic rays. Cosmic rays vary
>greatly in intensity at times, being largely affected by changes in
>the earth's magnetic field. Magnetic storms on the sun sometimes
>increase the cosmic rays a thousandfold for a few hours. The earth's
>magnetic field has been both stronger and weaker in past millenniums.
>And since the explosion of nuclear bombs, the worldwide level of
>carbon 14 has increased substantially.
>
>On the other hand, the proportion is affected by the quantity of
>stable carbon in the air. Great volcanic eruptions add measurably to
>the stable carbon-dioxide reservoir, thus diluting the radiocarbon. In
>the past century, man's burning of fossil fuels, especially coal and
>oil, at an unprecedented rate has permanently increased the quantity
>of atmospheric carbon dioxide. (More details on these and other
>uncertainties in the carbon-14 clock were given in the April 8, 1972,
>issue of Awake!)
All these effects are included in the chart.
>
>Dendrochronology-Dating by the Growth Rings of Trees
>
>Faced with all these fundamental weaknesses, the radiocarbon people
>have turned to standardizing their dates with the help of wood samples
>dated by counting tree rings, notably those of bristlecone pines,
>which live hundreds and even thousands of years in the southwestern
>United States. This field of study is called dendrochronology.
>
>So the radiocarbon clock is no longer regarded as yielding an absolute
>chronology but one which measures only relative dates. To get the true
>date, the radiocarbon date has to be corrected by the tree-ring
>chronology. Accordingly, the result of a measurement of radiocarbon is
>referred to as a "radiocarbon date." By referring this to a
>calibration curve based on tree rings, the absolute date is inferred.
>
>This is sound for as far back as the bristlecone ring count is
>reliable. The problem now comes up that the oldest living tree whose
>age is known goes back only to 800 C.E.
Wrong. According to http://www.sonic.net/bristlecone/intro.html the
oldest bristlecone pine is 4,767 years old which puts it back to about
2,763 BCE.
>In order to extend the scale,
>scientists try to match overlapping patterns of thin and thick rings
>in pieces of dead wood found lying nearby. By patching together 17
>remnants of fallen trees, they claim to go back over 7,000 years.
>
>But the tree-ring standard does not stand alone either. Sometimes they
>are not sure just where to put one of the dead pieces, so what do they
>do? They ask for a radiocarbon measurement on it and use that as a
>guide in fitting it in. It reminds one of two lame men with only one
>crutch between them, who take turns using it, one leaning for a while
>on his partner, then helping to hold him up.
Not completely correct.
1. Tree ring sequences look at the width of the rings (narrow in a bad
year, wide in a good one). By matching the wide/narrow pattern it is
not impossible to determine when two pieces from different trees from
the same srea overlap.
2. Where two rings have the same C14 date then there is a good chance
that they have the same real date (even if we don't actually know the
real date exactly). This can help with the matching of wide/narrow
bands.
3. Varves also contain Carbon. The site on Lake Suigetsu above says:
"This sequence of annually laminated sediments not only forms a unique
continuous palaeoenvironmental record after the last interglacial but
also permits us to reconstruct a complete 14C calibration extending
back to at least 45 ka BP, and probably even more by means of combined
isotope enrichment and AMS 14C dating[1]. We have performed AMS 14C
measurements on more than 250 terrestrial macrofossil samples of the
annual laminated sediments from lake Suigetsu." No problem of
matching tree rings here - all the varves are in a single sequence at
the bottom of the Lake.
>
>One must wonder at the miraculous preservation of loose bits of wood
>lying so long in the open. It would seem they might have been washed
>away by heavy rainfall or picked up by passersby for firewood or some
>other use. What has prevented rot or insect attack? It is credible
>that a living tree might withstand the ravages of time and weather, an
>occasional one surviving for a thousand years or more. But dead wood?
>For six thousand years? It strains credibility. Yet this is what the
>older radiocarbon dates are based on.
Incredulity is no evidence of absence. Do they have evidence that the
scientists who found the wood were mistaken about its age?
>
>Nevertheless, the radiocarbon experts and the dendrochronologists have
>managed to put aside such doubts and smooth over the gaps and
>inconsistencies, and both feel satisfied with their compromise. But
>how about their customers, the archaeologists? They are not always
>happy with the dates they get back on the samples they send in. One
>expressed himself this way at the Uppsala conference:
>
>"If a carbon-14 date supports our theories, we put it in the main
>text. If it does not entirely contradict them, we put it in a
>footnote. And if it is completely 'out of date,' we just drop it."
Say "Source please." to this and then check it.
>
>Some of them still feel that way. One wrote recently concerning a
>radiocarbon date that was supposed to mark the earliest domestication
>of animals:
>
>"Archeologists [are coming] to have second thoughts about the
>immediate usefulness of radiocarbon age determinations simply because
>they come out of 'scientific' laboratories. The more that confusion
>mounts in regard to which method, which laboratory, which half-life
>value, and which calibration is most reliable, the less we
>archeologists will feel slavishly bound to accept any 'date' offered
>to us without question."
>
>The radiochemist who had supplied the date retorted: "We prefer to
>deal with facts based on sound measurements-not with fashionable nor
>emotional archeology."
Say "Source please." to this and then check it.
>
>If scientists disagree so sharply about the validity of these dates
>reaching back into man's antiquity, is it not understandable that
>laymen might be skeptical about news reports based on scientific
>"authority," such as those quoted at the head of this series of
>articles?
The whole point of science is to disagree. *Everything* is up for
criticism and retesting. There is currently an experiment going on to
recheck Einstein's Theory of Gravity. Scientists disagreeing is the
norm of science.
Been done. Came in about 1350 CE IIRC.
>
>In any event, attempts to extend the time range have little
>significance as long as the greater problems remain unsolved. The
>older the sample is, the more difficult it is to ensure the complete
>absence of slight traces of younger carbon. And the farther we try to
>go beyond the few thousand years for which we have a reliable
>calibration, the less we know about the atmospheric level of carbon 14
>in those ancient times.
Wrong - I have already mentioned the calibration done to check C14
agains known dates.
>
>Several other methods have been studied for dating events in the past.
>Some of these are related indirectly to radioactivity, such as the
>measurement of fission tracks and radioactive halos. Some involve
>other processes, such as the deposition of varves (layers of sediment)
>by streams flowing from a glacier and the hydration of obsidian
>artifacts.
>
>Amino-Acid Racemization
I can't help you with this I'm afraid. Perhaps someone else can.
Ask for the reference and check it.
>
>Even that is not the end of the story. One of the Sunnyvale bones was
>tested for radiocarbon, both by the counting of beta particles from
>decaying atoms and by the newer atom-counting method. These gave
>roughly concordant values. The average was only 4,400 years!
>
>What can we believe? Obviously some of the answers are terribly wrong.
>Should we put more confidence in the radiocarbon date, since there is
>longer experience in using it? But even with it, different samples
>from the same bone varied from 3,600 to 4,800 years. Perhaps we should
>just admit, in the words of the scientist quoted previously, "Maybe
>all of them are wrong.""
And maybe we shouldn't.
Hope that helps,
rossum
--
The Ultimate Truth is that there is no Ultimate Truth
Derek Potter
Sure and scientists take huge care to make sure a) that accidental
contamination does not happen b) that possible errors are quantified.
>
>The most serious fault in radiocarbon-dating theory is in the
>assumption that the level of carbon 14 in the atmosphere has always
>been the same as it is now. That level depends, in the first instance,
>on the rate at which it is produced by cosmic rays. Cosmic rays vary
>greatly in intensity at times, being largely affected by changes in
>the earth's magnetic field. Magnetic storms on the sun sometimes
>increase the cosmic rays a thousandfold for a few hours. The earth's
>magnetic field has been both stronger and weaker in past millenniums.
>And since the explosion of nuclear bombs, the worldwide level of
>carbon 14 has increased substantially.
>
>On the other hand, the proportion is affected by the quantity of
>stable carbon in the air. Great volcanic eruptions add measurably to
>the stable carbon-dioxide reservoir, thus diluting the radiocarbon. In
>the past century, man's burning of fossil fuels, especially coal and
>oil, at an unprecedented rate has permanently increased the quantity
>of atmospheric carbon dioxide. (More details on these and other
>uncertainties in the carbon-14 clock were given in the April 8, 1972,
>issue of Awake!)
So what? This makes a tiny difference in C14 production rates
introducing at most a few percent error - hardly enough to convert a
50,000y age to the 6000y required for JW floodology.
Oh pulhease! The entire effort is designed to improve the accuracy of
dating methods, not to prove they work.
>One must wonder at the miraculous preservation of loose bits of wood
>lying so long in the open. It would seem they might have been washed
>away by heavy rainfall or picked up by passersby for firewood or some
>other use. What has prevented rot or insect attack? It is credible
>that a living tree might withstand the ravages of time and weather, an
>occasional one surviving for a thousand years or more. But dead wood?
>For six thousand years? It strains credibility. Yet this is what the
>older radiocarbon dates are based on.
Then account for the fact that they show quite old C14 dates.
>Nevertheless, the radiocarbon experts and the dendrochronologists have
>managed to put aside such doubts and smooth over the gaps and
>inconsistencies, and both feel satisfied with their compromise. But
>how about their customers, the archaeologists? They are not always
>happy with the dates they get back on the samples they send in. One
>expressed himself this way at the Uppsala conference:
>
>"If a carbon-14 date supports our theories, we put it in the main
>text. If it does not entirely contradict them, we put it in a
>footnote. And if it is completely 'out of date,' we just drop it."
A prime example of quote mine argumentation.
>Some of them still feel that way. One wrote recently concerning a
>radiocarbon date that was supposed to mark the earliest domestication
>of animals:
>
>"Archeologists [are coming] to have second thoughts about the
>immediate usefulness of radiocarbon age determinations simply because
>they come out of 'scientific' laboratories. The more that confusion
>mounts in regard to which method, which laboratory, which half-life
>value, and which calibration is most reliable, the less we
>archeologists will feel slavishly bound to accept any 'date' offered
>to us without question."
>
>The radiochemist who had supplied the date retorted: "We prefer to
>deal with facts based on sound measurements-not with fashionable nor
>emotional archeology."
>
>If scientists disagree so sharply about the validity of these dates
>reaching back into man's antiquity, is it not understandable that
>laymen might be skeptical about news reports based on scientific
>"authority," such as those quoted at the head of this series of
>articles?
Most laymen are smart enough to tell the difference wetween bickering
among professionals and the disingenuous outpourings of religious
crackpots determined to undermine science education.
Which you silly, silly man, would just mean that you would get a
younger apparent date.
>And the farther we try to
>go beyond the few thousand years for which we have a reliable
>calibration, the less we know about the atmospheric level of carbon 14
>in those ancient times.
the why do the dates not stop at x thousand years?
>
>Several other methods have been studied for dating events in the past.
>Some of these are related indirectly to radioactivity, such as the
>measurement of fission tracks and radioactive halos. Some involve
>other processes, such as the deposition of varves (layers of sediment)
>by streams flowing from a glacier and the hydration of obsidian
>artifacts.
Yup and isochron dating is perfect.
Ahem. You have just shown that a method based on racemization may be
unreliable if the history is unknown. Most people would have guessed
that. You have also inadvertently shown that C14 is reliable. How
could that make "all of them wrong"? Do you think perhaps the
"scientist" was making a wry comment on the acknowledged degree of
uncertainty in *this particular case*? Or are you intent on creating a
specious case against all *methods* of dating.
"You" of course is the author of the silliness, not you, lodger.
Frank Reichenbacher
"eNo" <ab...@yahoo.com> wrote in message
news:5lghc.17$Ts...@dfw-service2.ext.ray.com...
> BTW, I've read (as in the quote below), that tree-ring calibration has
> its own set of gotchas. Can anyone confirm this, and/or detail methods
> developed to aleviate the problem described below?
>
> "To determine the extent of correction necessary to render the
> radiocarbon method reliable, dendrochronologists devised a plan to
> control the radiocarbon dates by building a chronology of tree rings of
> the white bristlecone pine, the longest living tree. The method caught
> the fancy of the radiocarbon researchers. However, three or four rings
> formed in one year is not uncommon, especially if the tree grows on a
> slope, with the ground several times in a year turning wet and dry
> because of rapid outflow of water (Glueck et al., Botanical Review, 7,
> 649-713; and 21, 245-365). And certainly the building of tree 'ladders,'
> or carrying on the count from one tree to another may cause erroneous
> conclusions. One and the same year may be dry in South California and
> wet in the northern part of the state."
> http://www.varchive.org/ce/c14.htm
Dendrochronologists don't just count rings. In fact, the rings are arguably
of secondary importance. Tree-ring dating relies on studies of the
*patterns* of tree-ring formation. In poor years rings are small and close
together, in good years they are fat and widely spaced. And yes, these
features can differ from one site to another in a given region. These growth
patterns are correlated between samples within and between regions to
develop a complete series of cross-correlated chronologies. It is highly
accurate to about 10,000 ybp. Moreover, the system is independent of
radio-carbon dating.
Say you have a core taken from a log salvaged from an archaeological site of
suspected fairly recent age. If you have reason to believe that the salvaged
log is not too much older than trees in the local forest, you would take a
core sample from a tree in the local forest and then lay the two cores
together and match up the regions of similar growth patterns on each core to
see if patterns on the living tree sample overlaps with the patterns on the
older log sample. If you can match up regions then you can establish a
continuous dating series that would include the structure that the log came
from.
If you repeat this process many hundreds or thousands of times across
regions and the whole world, using many different tree species in numerous
habitats you can build a very accurate and reliable dating system.
So the quote is correct in pointing out the obvious fact that failure to
account for sources of error would lead to erroneous dates. It is highly
incorrect, however, in the implication that scientists have not done so.
This is why, obviously, we have a *science* of dendrochronology instead of a
hobby of tree-ring counting.
Radiocarbon calibration does not rely solely on tree-rings to correct
radiocarbon dates. Here is a link:
http://packrat.aml.arizona.edu/Journal/v40n3/editorial.html
that discusses the 1998 calibration curve. Note that the calibration also
incorporates datasets from corals and varves. It mentions also that
"thermoluminescence, speleothems and various laminated sediments" are
alternative dating methods that were *not* incorporated into the calibration
curve. These additional methods are available to provide even more data if
that were necessary.
Note that the graph shows the difference between the actual radiocarbon date
that comes out of the mass-spectrometer and the dates that the calibration
says it should be. The difference is between 3 and 5% of the age. We are not
talking about an order of magnitude of error, only a few percent. So
independent dating methods confirm that even uncorrected radiocarbon dates
are only off by a few years.
Here is a link to more web information: http://www.c14dating.com/index.html
For general information http://www.wikipedia.org is always a great source.
Frank
eNo
<snip of good info>
Thanks!
--
ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø¤º°`°º¤ø,,,,ø¤º
eNo
"If you can't go fast, go long."
ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø¤º°`°º¤ø,,,,ø¤º
Tom McDonald
> BTW, I've read (as in the quote below), that tree-ring calibration has
> its own set of gotchas. Can anyone confirm this, and/or detail methods
> developed to aleviate the problem described below?
>
> "To determine the extent of correction necessary to render the
> radiocarbon method reliable, dendrochronologists devised a plan to
> control the radiocarbon dates by building a chronology of tree rings of
> the white bristlecone pine, the longest living tree. The method caught
> the fancy of the radiocarbon researchers. However, three or four rings
> formed in one year is not uncommon, especially if the tree grows on a
> slope, with the ground several times in a year turning wet and dry
> because of rapid outflow of water (Glueck et al., Botanical Review, 7,
> 649-713; and 21, 245-365). And certainly the building of tree 'ladders,'
> or carrying on the count from one tree to another may cause erroneous
> conclusions. One and the same year may be dry in South California and
> wet in the northern part of the state."
> http://www.varchive.org/ce/c14.htm
>
There isn't one dendrochronological profile for the entire
earth. Such profiles are, and have to be, developed regionally,
as local conditions will affect the rings in differently from
region to region. In this way, some observations about
paleoclimates can be made.
If anyone thinks that dendrochronologists make bone-headed,
simplistic ring counts without taking into consideration
anything else, one would be quite wrong. As with radiometric
dating, the simplistic views about the techniques are belied by
their actual practice and practitioners. If anyone thinks that
non-scientists, or those with minimal scientific background, are
likely to come up with 'gotchas' about these techniques that the
experts haven't considered, researched, had conferences about
and published in peer reviewed journals, I'd invite them to
present the gotchas to a leading academic in the fields. If
correct, you'd get a big thank you, and perhaps even mention in
the literature; if wrong, perhaps you'd have the grace to admit
it and not continue repeating falsehoods.
Tom McDonald
Tom McDonald
<snip>
> Nevertheless, the radiocarbon experts and the dendrochronologists have
> managed to put aside such doubts and smooth over the gaps and
> inconsistencies, and both feel satisfied with their compromise. But
> how about their customers, the archaeologists? They are not always
> happy with the dates they get back on the samples they send in. One
> expressed himself this way at the Uppsala conference:
>
> "If a carbon-14 date supports our theories, we put it in the main
> text. If it does not entirely contradict them, we put it in a
> footnote. And if it is completely 'out of date,' we just drop it."
>
Lodger,
I've read hundreds of archaeological reports from primary
sources. Where radiocarbon and/or dendrochronological dates are
given, in almost every case, _all_ of the dates are given,
including the outliers. In almost every case I can recall, the
apparent odd-ball dates are discussed wrt possible
contamination, or some other possible cause of error; but they
are given, and are available to others who read the reports.
It is true that when such reports are presented to a more
general audience, especially when done so by journalists, the
apparently anomalous dates are often ignored or brushed aside.
But in the original reports, the ones that scientists actually
rely on, this is uncommon, and if it happens, is cause for
concern about the author's methodology.
To the extent that fundamentalists rely on journalistic sources
for their information, they are allowing a source of possible
error into their considerations that no scientist worth her salt
would allow.
The archaeological communities are also forever discussing
dating techniques, and are far more critical of them than any
fundie. The presumed scientific conspiracy to present a single,
monolithic interpretation of the world is poppycock, and anyone
who says otherwise is itching for a fight.
Tom McDonald
<snip>
Harlequin
news:108ba00...@corp.supernews.com:
[snip]
> If anyone thinks that dendrochronologists make bone-headed,
> simplistic ring counts without taking into consideration
> anything else, one would be quite wrong.
[snip]
As usual the creationists "debunk" the super-simplified
page or two description of the methods that appear in
pop science accounts or textbooks meant for young children.
xtmprs...@erols.com
The c14 level is not assumed to be constant. The author is lying.
> That level depends, in the first instance,
> on the rate at which it is produced by cosmic rays. Cosmic rays vary
> greatly in intensity at times, being largely affected by changes in
> the earth's magnetic field. Magnetic storms on the sun sometimes
> increase the cosmic rays a thousandfold for a few hours.
Magnetic storms on the sun do not produce cosmic rays. They produce
solar wind. Cosmic rays come from another source. The author is lying.
But, if solar storms did produce lots of c14 for a few hours,
plants would not take it up instantly. It would be mixed with
all the other carbon that already existed, raising the
c14 ratio slightly. Repeated solar storms would just raise
the average production of c14. Over long periods of time,
the c14 production rate average out to some value, and
the c14 method would still work.
Even if solar storms did produce c14, the statement is still a lie.
> The earth's
> magnetic field has been both stronger and weaker in past millenniums.
C14 dates are calibrated to correct for this.
The author implies that this magnetic field variation invalidates
c14 dating. The athor is lying.
> And since the explosion of nuclear bombs, the worldwide level of
> carbon 14 has increased substantially.
>
Atomic bombs throw plutonium and cesium and strontium and other
things like that around. They do not make c14. The author is lying.
Even if they did make c14, this would not affect dates of things
that died before 1943. The author is lying again.
> On the other hand, the proportion is affected by the quantity of
> stable carbon in the air. Great volcanic eruptions add measurably to
> the stable carbon-dioxide reservoir, thus diluting the radiocarbon.
Volcanos are always erupting, adding c12 to the air.
In the long run its a constant process that does not affect c14 dates.
In the short run the c14 dating method can be corrected for an
eruption big enough to cause a measurable effect. The author is lying.
> In
> the past century, man's burning of fossil fuels, especially coal and
> oil, at an unprecedented rate has permanently increased the quantity
> of atmospheric carbon dioxide. (More details on these and other
> uncertainties in the carbon-14 clock were given in the April 8, 1972,
> issue of Awake!)
>
This does not affect objects older than the beginning of the
industrial revolution. The author is lying.
In the american southwest the climate has been suitable for the
preservation of wood for 12,000 yeears. Before that the climate
was too wet for wood to survive.
After the climate became hot and dry indians used wood to build
parts of their houses. This wood was not lying around to be
washed away or be used for firewood. It remained as part of the
shelter for thousands of years. The tree ring pattern can be matched to
other logs to create an overlapping sequence extending from the present
to 10,000 years ago. The author is lying.
>
> Nevertheless, the radiocarbon experts and the dendrochronologists have
> managed to put aside such doubts and smooth over the gaps and
> inconsistencies, and both feel satisfied with their compromise.
The gaps and inconsistencies are not big enough to turn
20,000 years into 5,000 years. The author is lying.
> But
> how about their customers, the archaeologists? They are not always
> happy with the dates they get back on the samples they send in. One
> expressed himself this way at the Uppsala conference:
>
> "If a carbon-14 date supports our theories, we put it in the main
> text. If it does not entirely contradict them, we put it in a
> footnote. And if it is completely 'out of date,' we just drop it."
>
Obviously wrong data is obviously wrong. It is not used.
This is simalar to creationists rejecting any facts that contradict
their religion, except in the creationists case, nearly all
data is rejected, while scientists reject the few c14
dates that contradict the many c14 dates. The author is lying.
> Some of them still feel that way. One wrote recently concerning a
> radiocarbon date that was supposed to mark the earliest domestication
> of animals:
>
> "Archeologists [are coming] to have second thoughts about the
> immediate usefulness of radiocarbon age determinations simply because
> they come out of 'scientific' laboratories. The more that confusion
> mounts in regard to which method, which laboratory, which half-life
> value, and which calibration is most reliable, the less we
> archeologists will feel slavishly bound to accept any 'date' offered
> to us without question."
>
> The radiochemist who had supplied the date retorted: "We prefer to
> deal with facts based on sound measurements-not with fashionable nor
> emotional archeology."
>
Scientists are having a dispute over observations and experiments.
Creationists don't care about either. The base their opinions on
a written down 4000 year old creation myth. they never change their mind
no matter what dates come out of a lab.
Which do you think is more reliable?
> If scientists disagree so sharply about the validity of these dates
> reaching back into man's antiquity, is it not understandable that
> laymen might be skeptical about news reports based on scientific
> "authority," such as those quoted at the head of this series of
> articles?
>
If JWs reject any facts that disagree with their religion,
is it not understandable that they should not be trusted to tell
the truth about those facts?
Its interesting that the elder is using an article this old.
Wasn't anything more recent available? The shroud of
turin was dated this way long ago.
> In any event, attempts to extend the time range have little
> significance as long as the greater problems remain unsolved. The
> older the sample is, the more difficult it is to ensure the complete
> absence of slight traces of younger carbon. And the farther we try to
> go beyond the few thousand years for which we have a reliable
> calibration, the less we know about the atmospheric level of carbon 14
> in those ancient times.
>
We have reliable calibration for farther back than a few thousand years.
The author is lying.
> Several other methods have been studied for dating events in the past.
> Some of these are related indirectly to radioactivity, such as the
> measurement of fission tracks and radioactive halos. Some involve
> other processes, such as the deposition of varves (layers of sediment)
> by streams flowing from a glacier and the hydration of obsidian
> artifacts.
>
> Amino-Acid Racemization
>
> The racemization of amino acids is another dating method used. But
> what does "racemization" mean?
I can't tell you much about amino acid racimization.
But given the authors repeated lying about c14 dating,
can he be trusted to tell the truth about any dating method?
The bible of course, cannot be wrong, regardless of any
discrepancies found anywhere.
Derek Potter
>> The racemization of amino acids is another dating method used. But
>> what does "racemization" mean?
>
>I can't tell you much about amino acid racimization.
>But given the authors repeated lying about c14 dating,
>can he be trusted to tell the truth about any dating method?
You don't need to know all that much. The JW article is just
regurgi-babble, the author clearly a) doesn't know which points in his
exposition are relevant b) just wants to blind his audience with
irrelevant science.
From general principals, regardless of anything specific to amino
acids: All racemization is an approach to an equilibrium. The energy
diffence between two racemers is very small but the energy hill
between them is considerably larger. Thus both the equilibrium ratio
and the rate of approach to it are very temperature dependent.
The whole theory of racemic dating is well understood otherwise
scientists would not have come up with such an obscure technique.
They automatically anticipate the trite objections raised by
creationists plus a whole lot more. Obviously they note the sources of
errors and allow for them, both by correcting their best estimates and
by stating the margin of uncertainty.
Barbarossa
"lodger" <thel...@yahoo.com> schreef in bericht
news:4b9cfdb7.04042...@posting.google.com...
I liked to read this post! Thank you for posting it.A lot of uncertainties
indeed
and then attacking creationists for lack of evidence beyond reasonble doubt.
Kind Regards,
Barbarossa
Barbarossa
"eNo" <ab...@yahoo.com> schreef in bericht
news:5lghc.17$Ts...@dfw-service2.ext.ray.com...
> BTW, I've read (as in the quote below), that tree-ring calibration has
> its own set of gotchas. Can anyone confirm this, and/or detail methods
> developed to aleviate the problem described below?
>
> "To determine the extent of correction necessary to render the
> radiocarbon method reliable, dendrochronologists devised a plan to
> control the radiocarbon dates by building a chronology of tree rings of
> the white bristlecone pine, the longest living tree. The method caught
> the fancy of the radiocarbon researchers. However, three or four rings
> formed in one year is not uncommon, especially if the tree grows on a
> slope, with the ground several times in a year turning wet and dry
> because of rapid outflow of water (Glueck et al., Botanical Review, 7,
> 649-713; and 21, 245-365). And certainly the building of tree 'ladders,'
> or carrying on the count from one tree to another may cause erroneous
> conclusions. One and the same year may be dry in South California and
> wet in the northern part of the state."
I once spoke to a gardener and he told me that in years of much fluctuation
in moist and temperature trees can actually produce more than one ring a
year. Sometimes 4 a year. That is interesting huh? This damages the practice
of counting the rings very hard since nobody can actually tell the weather
pattern in let's say 1000 BC. Same goes for icerings in icecilinders. In
years
of more fluctuation more than 1 icering can be produced a year.
Kind Regards,
Barbarossa
Phil Roberts
<fa07...@skynet.be> leapt forth and uttered:
Did your gardener cut down the same tree every year to test this
hypothesis? Sounds rather dubious to me.
--
Phil Roberts | Dork Pretending To Be Hard | http://www.flatnet.net/
Seppo Pietikainen
> "lodger" <thel...@yahoo.com> schreef in bericht
> news:4b9cfdb7.04042...@posting.google.com...
>
<snip>
>
> Kind Regards,
> Barbarossa
>
>
I bet you weren't as happy with the reply to the question, were you?
Seppo P.
Gary Bohn
"Barbarossa" <fa07...@skynet.be> wrote in message
news:40866e99$0$11075$a0ce...@news.skynet.be...
are too stupid to take this into account! Instead of making blanket
assumptions that everyone thinks as slowly as you do, maybe ask some of them
how they correct for problems. By the way, Hovind isn't a scientist!
--
Conservatism is not about tradition and morality, hasn't been for many
decades...It is about the putative biological and spiritual superiority of
the wealthy.
Greg Bear
Gary Bohn
Bennett Standeven
> The following is from an Awake! magazine published in 1986. Can
> somebody please take a point-by-point analysis of this blurb and do
> any debunking required for me? Especially the points related to Del
> Mar man and the Sunnyvale skeleton in regards to Amino-Acid
> Racemization.
>
> Thanks in advance, you guys rock,
>
> Lodger
>
> "Errors in the Radiocarbon Clock
>
> The radiocarbon clock looked very simple and straightforward when it
> was first demonstrated, but it is now known to be prone to many kinds
> of error. After some 20 years' use of the method, a conference on
> radiocarbon chronology and other related methods of dating was held in
> Uppsala, Sweden, in 1969. The discussions there between chemists who
> practice the method and archaeologists and geologists who use the
> results brought to light a dozen flaws that might invalidate the
> dates. In the 17 years since then, little has been accomplished to
> remedy these shortcomings.
>
> One nagging problem has always been to ensure that the sample tested
> has not been contaminated, either with modern (live) carbon or with
> ancient (dead) carbon.
Heh. If carbon dating is as awful as creationists claim, how come this
matters?
It is of course true.
> A bit of wood, for example, from the heart of
> an old tree might contain live sap.
How old is "old", I wonder...
> Or if that has been extracted with an organic solvent (made from dead
> petroleum), a trace of the solvent might be left in the portion analyzed.
> Old buried charcoal might be penetrated by rootlets from living plants.
> Or it might be contaminated with much older bitumen, difficult to remove.
> Live shellfish have been found with carbonate from minerals long buried
> or from seawater upwelling from the deep ocean where it had been for
> thousands of years. Such things can make a specimen appear either
> older or younger than it really is.
>
This makes sense. But only the first case could produce a specimen
that appears younger than it actually is.
> The most serious fault in radiocarbon-dating theory is in the
> assumption that the level of carbon 14 in the atmosphere has always
> been the same as it is now.
This isn't an assumption; merely a simplification in a typical
presentation of the idea. Actually, we have computed the level of C14
in the atmosphere over the past few millenia; we use this information
in determining the carbon dates.
> That level depends, in the first instance, on the rate at which it
> is produced by cosmic rays. Cosmic rays vary greatly in intensity
> at times, being largely affected by changes in the earth's magnetic field.
> Magnetic storms on the sun sometimes increase the cosmic rays a
> thousandfold for a few hours. The earth's magnetic field has been both
> stronger and weaker in past millenniums.
True enough...
> And since the explosion of nuclear bombs, the worldwide level of
> carbon 14 has increased substantially.
>
I dunno... This seems implausible.
> On the other hand, the proportion is affected by the quantity of
> stable carbon in the air.
Yeah, the proportion of stable to unstable carbon depends on how much
carbon is stable!
> Great volcanic eruptions add measurably to the stable carbon-dioxide
> reservoir, thus diluting the radiocarbon.
This makes sense, but I don't know if its actually true. (Volcanic
Carbon may already be rich in C14, for all I know). If it is, we could
use it to date the volcanic eruptions.
> In the past century, man's burning of fossil fuels, especially coal and
> oil, at an unprecedented rate has permanently increased the quantity
> of atmospheric carbon dioxide. (More details on these and other
> uncertainties in the carbon-14 clock were given in the April 8, 1972,
> issue of Awake!)
As I stated above, none of them is a problem for the dating method,
since we have computed C14 levels throughout history. One key method
uses:
>
> Dendrochronology-Dating by the Growth Rings of Trees
>
> Faced with all these fundamental weaknesses, the radiocarbon people
> have turned to standardizing their dates with the help of wood samples
> dated by counting tree rings, notably those of bristlecone pines,
> which live hundreds and even thousands of years in the southwestern
> United States. This field of study is called dendrochronology.
>
> So the radiocarbon clock is no longer regarded as yielding an absolute
> chronology but one which measures only relative dates.
"No longer regarded"? I doubt they ever thought C14 levels were
constant. And the dates it produces are still absolute, even if they
contain systematic error. A relative date means that we can only tell
if one sample is older than another, but not how old each one is by
itself.
> To get the true date, the radiocarbon date has to be corrected by the
> tree-ring chronology. Accordingly, the result of a measurement of
> radiocarbon is referred to as a "radiocarbon date." By referring this
> to a calibration curve based on tree rings, the absolute date is inferred.
Of course still other dating methods are used as well.
> This is sound for as far back as the bristlecone ring count is
> reliable. The problem now comes up that the oldest living tree whose
> age is known goes back only to 800 C.E.
Actually, back to around 1800 BCE, IIRC.
> In order to extend the scale,
> scientists try to match overlapping patterns of thin and thick rings
> in pieces of dead wood found lying nearby. By patching together 17
> remnants of fallen trees, they claim to go back over 7,000 years.
>
> But the tree-ring standard does not stand alone either. Sometimes they
> are not sure just where to put one of the dead pieces, so what do they
> do? They ask for a radiocarbon measurement on it and use that as a
> guide in fitting it in. It reminds one of two lame men with only one
> crutch between them, who take turns using it, one leaning for a while
> on his partner, then helping to hold him up.
>
Sounds like a very good description of science...
> One must wonder at the miraculous preservation of loose bits of wood
> lying so long in the open.
Duh, maybe they weren't lying in the open?
> It would seem they might have been washed away by heavy rainfall or
> picked up by passersby for firewood or some other use.
Duh, maybe they were too heavy?
[...snip argument from strained credulity...]
>
[...snip turf war between archaeologists and chemists...]
>
> If scientists disagree so sharply about the validity of these dates
> reaching back into man's antiquity, is it not understandable that
> laymen might be skeptical about news reports based on scientific
> "authority," such as those quoted at the head of this series of
> articles?
Or, say, the claims made in _this_ article?
>
> Direct Counting of Carbon 14
>
Don't see anything wrong here.
> Amino-Acid Racemization
>
> The racemization of amino acids is another dating method used. But
> what does "racemization" mean?
>
> Amino acids belong to the group of carbon compounds that have four
> different groups of atoms attached to a central carbon atom. The
> tetrahedral arrangement of the groups makes the molecule asymmetrical
> as a whole.
Rather, it makes the molecule three-dimensional, hence _potentially_
asymmetric.
(A 2D molecule could switch handedness simply by turning over.)
Never heard of this event, so I can't comment.
> The big uncertainty in racemization ages is the unknown thermal
> history of the specimen. As mentioned above, the rate of racemization
> is extremely sensitive to temperature. If the temperature goes up by
> 25 degrees Fahrenheit (14° C), the reaction goes ten times as fast.
> How could anyone know what temperatures the bones could have been
> exposed to so many years in the past? How many summers might they have
> lain bare under a hot California sun? Or might they even have been in
> a campfire or a forest fire? Besides the temperature, other factors
> have been found to affect the rate greatly, such as the pH (degree of
> acidity). One report says: "Amino acids in sediments show an initial
> rate of racemization almost an order of magnitude (tenfold) faster
> than the rate observed for free amino acids at a comparable pH and
> temperature."
>
I think I see why I never heard of it....
Gary Bohn
"Derek Potter" <m...@privacy.net> wrote in message
news:svac80hmbuou43n24...@4ax.com...
stupid to see as many potential problems with their methods as the fundies
are able to.
Aren't we lucky we have the fundies to show all the problems inherent in
research? Without them nobody would have known. Whew, what a lucky break for
science.
What is the variance between the mean intelligence of a scientist compared
to the mean intelligence of a fundy?
fundy brain_death()
{
My uncle only got his grade 6 and he was the smartest man I have ever
known;
}
rational recovery()
{
My ex-sister-in-law only get her grade 6 and she was dumb as a brick;
Richard Forrest
Wow! You spoke to a gardener, and he told you something that all the
scientists working on dendrochronology didn't know about. Gosh, they
must be stupid!
On the other hand, a little research will show that
dendrochronologists are well aware of this, and the methods they use
take it into account. Try googling 'dendrochronlogy' and see what you
find. Try this for starters:
http://www.ltrr.arizona.edu/skeletonplot/ringanomalies.htm
http://www.botanik.uni-bonn.de/conifers/topics/oldest.htm
http://www.eeob.iastate.edu/classes/bot404/docs/stem203.pdf
You'll find that scientists who have devoted a life-time to the study
of dendrochronology are rather better informed on the subject than
your gardener.
RF
Derek Potter
I'm sure fundies see a lot of things that sane people don't.
Matt Davis
<snip>
> I liked to read this post! Thank you for posting it.A lot of uncertainties
> indeed
> and then attacking creationists for lack of evidence beyond reasonble doubt.
>
> Kind Regards,
> Barbarossa
Any comments on the thorough debunking that followed?
Sapient Fridge
<thel...@yahoo.com> writes
>One must wonder at the miraculous preservation of loose bits of wood
>lying so long in the open.
The answer to this is that they often aren't in the open, wood in
anaerobic conditions (no oxygen) such as bogs will last an extremely
long time. Buried wood will last long enough to fossilise.
Wood in dry conditions such as tombs or caves will last pretty much
indefinitely. When I was in Egypt I saw a small, delicately carved boat
from a tomb which even had tiny wooden figures on it. The boat was
carved over 3000 years ago but looked like it was carved yesterday.
It really was awe inspiring to think of that carving just sitting
quietly in its tomb whilst entire civilisations in the rest of the world
appeared and disappeared again...
>One suggested application of this would be to date the Shroud of
>Turin, which some believe Jesus' body was wrapped in for burial. If
>radiocarbon dating was to show that the cloth is not that old, it
>would confirm the suspicions of doubters that the shroud is a hoax.
The text you are quoting from must be out of date, the shroud was C14
dated to around 1300 in 1988:
http://www.mcri.org/Shroud.html
When the date didn't give the date wanted people started trying to
discredit the dating mechanisms:
http://www.shroud.com/c14debat.htm
http://www.shroudstory.com/c14.htm
Of course if the C14 dating had given them the date they wanted there
they would not be trying to discredit the dating mechanism. There are a
lot of people out there who want it to be the real thing.
Radiocarbon dating is only one of many ways of dating things, most of
which match up rather nicely. If the earth really was only thousands of
years old you would expect at least some of the dating mechanisms to
show it.
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