Author: Chris Stassen Subject: FAQ: Age of Earth Debate Updated: 02/27/92 This is the firs
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Author: Chris Stassen
Subject: FAQ: Age of Earth Debate
Updated: 02/27/92
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This is the first of two postings generated by the debate. It contains
Bob [Bales]'s opening statement, my rebuttal, and Bob's closing remarks.
(The cross-in-the-mail format for the debate caused this division to make
the most sense; the debate wouldn't fit in a single article anyway.)
Bales Opening Statement =======================================================
===============================================================================
In this argument, I'll stick to the evidence which indicates the earth has a
young age. Any young-earth theory must also explain evidence that seems to
indicate that the earth is millions of years old. I've discussed some of this
in the newsgroup, but here I'll leave it for the rebuttal phase of the debate.
The arguments I use are of the same basic type as those of the old-earth
proponents: extrapolation of present-day trends into the past to determine
how long something could have been going on. These methods don't assign an
exact age; the rates and initial conditions are not exactly known. However,
since the "young" and "old" age ranges differ by 5 1/2 orders of magnitude,
it is easy to say which pieces of evidence favor which theory. Also, the
arguments I use here deal with the solar system, the earth, and man. They
do not deal with the age of the universe as a whole.
A couple of notes: for most of the arguments, I provide a background in case
you or someone who reads the record is not familiar with the subject area. I
hope I don't tell you too much that you already know. Also, since there has
been controversy on the net, unless otherwise indicated, all references and
quotes are taken from works which I have personally examined. Any conclusions
not specifically quoted are my own and may not agree with those who supply the
facts on which I base them. The supporting details are based on study,
briefer than I would like, done for this debate. Contrary to what is said
about me on the net, I do understand the scientific method and can follow and
evaluate the arguments. I do not claim to be an expert in the fields involved.
1. Short-period comets
Short period comets disinagrate rather quickly due to interaction with the sun
while in the inner portion of the solar system. Several references gave
conflicting values, from dozens to hundreds, of the number of orbits to be
expected. Paul Joss, of the Institute for Advanced Study in Princeton, NJ,
gives a value of 70 as an average. ("On the Origin of Short-Period Comets,"
_Astronomy and Astrophysics_, 25:271-273, June, 1973). He also gives an
average period for a class of short-period comets of 7 years, yielding an
average lifetime of around 500 years. With the average number of this class
which are visible any one time, a 4.5 billion year old universe requires that
at least several hundred million coments existing away from the sun have been
diverted into the solar system. If such a source of comets exists,
observations are consistent with an old solar system. If not, then the
existence of short-period comets indicates a young solar system.
About 1950, Jan Ort of the Netherlands postulated a cloud of comets
orbiting the sun far outside the planets. Note that, although observed
comet orbits are consistent with such a cloud, there is no direct evidence of
its existence: the presence of the comet source is derived from the *need* for
such a source in an old universe. Comets are supposedly diverted from the
reservoir by the influence of passing stars. The question is whether or not
enough comets will be supplied by this mechanism to agree with observations.
Paul Joss, in the above cited reference, calculates "no," by a factor of
40,000. On the other hand, A.H Delsemme ("Origin of Short-Period Comets,"
_Astronomy and Astrophysics_, 29:377-381, December, 1973) calculates that the
answer is "yes." Edger Everhart (University of Denver), who has reviewed both
calulations and has contributed his own theories ("Evaluation of Long- and
Short-periord Orbits," _Comets_, edited by Laurel L. Wilkening, University of
Arizona Press, 1982), the answer is unknown. By my implication, this
indicates that whether the old solar system theory adequately explains
observations is also unknown.
2. Presence of small particles in the solar system
This is an astronomical observation consistent with a young solar system but
which, as in the case of comets, requires extra assumptions if the solar
system is old.
Because of the forward motion of an object in orbit around the sun, the sun's
radition strikes it at an angle and exerts a backwards force. This is known
as the Poynting-Robinson effect. In the case particles on the order of 1 mm
or less in diameter, this force degrades the orbit, causing the particle to fall
into the sun within thousands to a few million years. In _Exploring the
Universe_ (Holt, Rinehart and Winston, 1969) -- my college astronomy text --
George Abell says: "The fact that we find small particles around the earth is
evidence that they are either newly formed or have newly arrived in our part
of the solar system." (page 365). Or, alternatively, evidence that the solar
system is far younger than commonly thought.
There may be some disagreement on this point. Referring to the zodaical light,
produced by reflection of sunlight from particles in space, _Introduction to
Astronomy_, 2nd edition (Cecilia Payne-Gaposchkin and Katherin Haramundanis,
Smithsonian Astronmical Observatory, 1970) says: "The observed brightness of
the zodaical light could be produced by a cloud of small bodies of the same
albedo as the moon, 1 mm in diameter and 5 miles apart or 10 feet in diameter
and 1000 miles apart." (page 272) Simply because the solar system is "known"
to be old, small particles are then rejected in favor of those up to the size
of baseballs. Yet, Stanley P. Waytt says, in _Principals of Astronomy_, 2nd
edition (1971) that the particles responsible of the zodical light are on the
order of 0.001 cm radius. He gives the likely source for these particles to be
comets, since we know that comets can create meteors. This sounds plausible,
but there are a few difficulties. First, of the three astronomy books
mentioned, only this one mentioned comets as a source and another, as mentioned
above, discountsd small particles almost entirely. This leads me to believe
that the comet source theory might not be an agreed upon answer. Second, the
distribution of meteors resulting from comets is highly non-uniform around the
earth's orbit, while the particles which cause the zodical light must be
uniformly distributed. Lastly, and most importantly, the theory that the
particle supply is constantly being replenished must make another assumption:
that the rates of supply and of destruction into the sun are roughly equal.
There are no theoretical reasons to expect these rates to balance. Neither,
apparently, are there calculations of the creation rate. The balencing is
derived from, and stated as a fact because of the presumed age of the solar
system. A young solar system does not need these extra assumptions and
theories.
3. Radiocarbon balance in the atmosphere
Radiactive carbon-14 is formed in the atmosphere through the action of
cosmic rays. The rate of formation depeneds on the cosmic-ray activity. The
rate of decay (amount decayed in mass/unit time) depends on the amount
present. Thus, the amount will increase until the decay rate balances the
production rate. Equilibrium will be reached in approximately 30,000 years.
Measurements of production and decay rates indicate that the amount has been
increasing for some time. According to V.R. Switzer, a European conference
reported two studies which showed the concentration has been increasing for
at least 10,000 years ("Radioactive Dating and Low-level Counting, _Science_,
157:726, August 11, 1967). The paper mentions, without details, that this
contradicts previous studies. However, there are other reports of increasing
concentration which I have not seen: "Production of C-14 by Cosmic 8 Ray
Neutrons," Richard E. Lingenfelter, _Reviews of Geophysics_, 1:51, February,
1963, and "Secular Variations in the Cosmic-Ray produced Carbon-14 in the
Atmosphere and Their Interpretations," Hans E. Suess, _Journal of Geophysical
Research_, 70:5947, December 1, 1965.
4. Erosion rate of the continents
For this, I cite an unusual (for me) reference: a creationist source. Stuart
Nevins calculates ("Evolution: the ocean says No!,"_Acts and Facts, Impact
Series No 8_ [published, I think, by the Creation Research Society] October,
1973.) I have a copy of this, which I read shortly after it came out, but
which I cannot now find. My discussion is based on my recollections and on
what Morris says in _Scientific Creationism_.
At the present rates at which sediments are being carried into the sea, the
entire mass of the continents above sea level would be worn away in about 14
million years. This, of course, is only an average. Some rocks would be worn
away more slowly and some faster.
The reply I have heard is that continuing uplift of the continents occurs so
they are not worn away. This is true, but it does not answer the problems.
The first is the resting place for the sediment. The amount of sediment in
the ocean is about twice the mass of the continents above sea level, it
could have been produced in 30 million years. 4.5 billion years would
have produced 150 times as much sediment at the present rate. Some say that
the sediment is carried by moving plates back into the mantle. However,
_Scientific Creationisms_ gives an unreferenced number thad only 10% of the
sediment can be so accounted for.
The second problem is the age of the present continental rocks. It obviously
must be less than the time since they were uplifed. Again, hard rocks would
remain longer than softer rocks, but why do we see so many rocks which are
supposedly so much older than the average rock "lifetime?" There should be
a great preponderance of younger rocks. Very old rocks would have to be
hard themselves, or would have had to have been protected by harder rocks.
In the case of rocks dated old, is there evidence that this is the case?
A note on erosion rate: the above-cited reference indicates that rate would
have been greater in the evolutionary past, presumably as a result of the
lack of plant cover to retard erosion. _Radioactivity in Geology_ (Eric
M. Durrance, John Wiley, no earlier than 1977), when dealing with another
subject, says the rate was lower in the past, but gives no details or number.
5.Radiogenic helium in the atmosphere
Helium is given off through the decay of uranium and thorium. Melvin Cook
(a creationist) indicates in a letter to _Nature_ ("Where is the Earth's
Radiogenic Helium, 179:213, January 26, 1957) that the present amout of
Helium-4 would have been generated in about 1 million years. (A reference
in _Scientific Creationism_, which I did not verify, gave the actual rate
as perhaps 100 times greater, which would change 1 million to 10,000.)
The assumption, as stated by Eric Durrance (see above), is that the helium
is light enough to escape into space. However, Dr. Cook gives a formula
for the escape rate as a function of temperature, and shows that, at
a temperature which I assume is the temperature of the upper atmosphere,
only 600 grams/year would escape.
I looked in in the index for _Nature_ for the remainer of the year and found
no answer or rebuttal.
6. Polonium halos
Polonium halos are not per se indications of a young earth, but of rapid
formation of rock, a process that would contradict assumption about the
earth's formation. (One paper by Gentry, which I have not seen, is "Time:
measured responses, _EOS, Transactions of the American Geophysical Union_,
May 29, 1979.)
Halos have been discussed in this takk.origins and although I have read the
positions on both sides, I am not completely familiar with the arguments
on possible alternate explanations, so I won't say much about it. My
purpose in bringing it up is to comment on something that has been said in the
group. It has been said that if an alternate explanation can be developed,
the usefulness of halos to young earth theories would be destroyed. This is
so! This would be true only if the alternate explanation were shown to be
correct. If someone shows that Gentry could be wrong, then he has shown that
the rocks in question could have formed over long periods, not that they did.
7. Human population growth
This factor, of course, only pertains to the length of time man has been around
and not to the age of the earth. Since this is outside the scope of the
original debate proposal, you may ignore it if you wish.
Basically, the present rate of population growth would have have populated the
earth in less than half of recorded history. By using lower rates of growth
and allowing for historic events that killed many people (e.g. the plague) a
model that humans have been around somewhat longer than recorded history fits
the present observed population. (Since present rates could vastly
overpopulate the earth, the charge that this model ignores eevents such as
the plague is unfounded.) It requires quite radical assumptions, however, to
make a supposed 500,000 to 1 million year human history "fit."
According to the 1988 World Almanac, the present rate of world population growth
is 1.7%. The rate in less-developed regions is higher, 2.0%. (Note that most
of the earth over most of history would be classed as "less developed.") As
recently as 1970-1975, the figures were 2.0% and 2.4% respectively. Using the
2% figure gives a population of 10^22 in 3000 years. Since unless one argues
some form of "Last Wednesdayism," people have been around at least as long as
recorded history, the actual rate must have been lower: an average growth rate
of 0.36% (about 1/5 the present rate) would produce approximately the present
population in 6000 years.
Much more severe assumptions are necessary to support a longer history. The
Word Almanac also has has a chart (derivation not given) showing the
population's increasing from 10,000,000 in 10,000 BC. I did not try to match
the shape of the curve, but the average growth rate from 10,000 BC would have
had to be only 0.05% -- 1/40 of the 1970-1975 rate. And the problem gets
worse: starting with a population of 2 in 500,000 BC demands a growth rate of
only 0.003% -- 1/600 the present rate -- from then to 10000 BC.
To look at it a slightly different way: if we take the average rate of growth
over 500,000 years to be a quite conservative 0.1%, it additionally requires
that 99% of the population be eliminated every 4000-5000 years to arrive at
the existing population. (The above growth numbers were calculated by
programs I wrote.)
The assumptions of the "young" model are much more realistic than those of the
"old" model.
I do not have the data needed for the calculations, but I suspect that the
growth of animal populations, even allowing for preditation, would also be
inconsistent with their being on earth for as long as evolution says.
Another factor is the total number of individuals, both human and animkal,
that would have lived over millions of years even if total population did
not increase rapidly. Had this number actually lived, we would undoubtedly
find more remains than we do.
In summary, does the evidence cited above *prove* the earth is young? No,
I don't claim that it does. As I've discussed above, there are
assumption which can be made to reconcile this evidence with an old earth.
In many, if not most, cases, the assumptions are made because the earth is
considered old. The evidence I have presented fits more simply and more
directly with a young earth model.
Stassen Rebuttal ==============================================================
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I'd like to start by saying that I'm quite pleased Bob has presented some
positive evidence for a young earth. His detractors ought to take note;
here he has presented seven methods which give a young age for the earth.
In my opening statement, I examined in detail Bob's one previously
proposed method - and it took over 100 lines. Since I am limited to 200
lines here, the examinations will necessarily be more brief. But I will
later expand on any of them in talk.origins at Bob's request - so that I
can't be accused of unfairly dismissing any of the methods.
I would like to make a few comments in general about the methods Bob has
proposed, before I examine each of them:
a) Bob seems to think that the earth is "young," but he has not given me
a specific value. I am defending 4.5 +- 0.1 billion years (a value
tied down to 2% tolerance). I presented two lines of evidence in my
opening statement (meteorite Rb-Sr and solar system model lead) which
support that value with direct measurements and calculations.
The methods Bob proposed support 3,000, 6,000, 12,000, or 25,000
years equally, and none of them calculate an age directly. If possible,
I would like him in his closing statement to propose a more precise
value (say, to 10% tolerance), and to tell me how he arrived at it.
b) Nearly all of the methods Bob proposed have the same flaw as the metals
one which I examined in my opening statement. There is either known
or strongly suspected to be a process which works in the reverse
direction of the process Bob is using for deriving a young age (I will
explain each later). And the reverse process is either not well
understood, or not likely uniform, or not measured accurately (yet).
Suppose there was a poorly understood process which turned lead
back into uranium at an unknown but significant rate. This process
works in the reverse direction from radioactive decay. I'm sure Bob
would justifiably ignore U/Pb dates if such a reverse process existed.
I will now briefly examine each of Bob's proposed methods:
# 1. Short-period comets
First off, the Oort hypothesis was proposed to explain the origin of long-
period comets, not short-period ones as Bob has claimed. That it explains
both is merely a "fringe benefit" (and maybe a point in its favor).
The capture of long-period comets into short-period orbits is the
process working in reverse of Bob's dating process.
Astronomers can calculate the "age" of a comet (estimate of the
time it has spent near the Sun by the gases it gives off). Short-period
comets have a wide range of ages, from "new" first-time-around ones to
"dead" ones that are barely detectable. This arrangement of data does not
make sense unless there is some mechanism which regularly injects "new"
short-period comets into the solar system. (If all short-period comets
were originally created 10k years ago, they should all be nearly "dead.")
The comet capture model is a better explanation than recent creation,
as recent creation "in situ" cannot account for the "youth" of s-p comets.
# 2. Presence of small particles in the solar system
There are three processes working against this proposed dating method:
1. For smaller particles - the ones Slusher expected to decay fastest -
radiation pressure effects balance and overcome the Poynting-Robertson
Effect. The particles responsible for the "zodiacal light" are of
a size that puts these two forces roughly at equilibrium - their orbits
would not decay at a significant rate.
2. As dust spirals past a planetary orbit, it can have its orbit radically
altered or be temporarily captured. There is no "uniform" decay of orbit.
3. Matter given off by comets and collisions of "minor planets" will
replenish dust at an unknown (but probably significant) rate.
Bob mentioned three astronomy texts (1969-1971), inconclusive on
comets as a source of dust. In 1973, comet Kohutek was estimated to be
giving off 30 tons of gas and dust *per second* when it was near the Sun.
Encke's Comet gave off 9 million tons of gas and dust (90% of its mass)
before dying. Astronomers have good reason to think that comets are a
major source of small particles in the inner parts of the solar system.
This "more simple" model simply ignores processes known to be
operating in the opposite direction. That hardly can make it more accurate.
# 3. Radiocarbon balance in the atmosphere
The [14]C/[12]C ratio depends on a number of factors including:
1. Its rate of production, influenced by both the strength of the earth's
magnetic field, and the cosmic-ray proton flux generated by the Sun.
2. The amount of carbon in "reservoirs" in the Earth, which is strongly
influenced by climatic conditions.
All of these factors vary; it is unjustified to assume that a non-
uniform level means non-equilibrium. The concentration of [14]C in the
atmosphere is calculated by performing [14]C dating on an object of known
age (and calculating the difference between the dating age and the real age).
The evidence indicates that it has been as high as 10% above its current
value, and as low as 10% below its current value at various times in the
past. It does not look like a process just now reaching equilibrium.
The "recent creation model" (with [14]C starting near but not at
equilibrium) does not account for samples which give [14]C dates older
than 10,000 years. Samples give ages to 50k years, which favors the
"equilibrium, varying [14]C/[12]C ratio" model.
# 4. Erosion rate of the continents
The processes which work against Bob's proposed dating method:
1. Crustal recycling. Much of the ocean floor is relatively young, so it
doesn't make any sense to expect 5 billion years of sediments there.
2. Sediment recycling by tectonic uplift. Many rocks exposed to erosion
today are sedimentary and have been eroded at least once already. One
cannot simply multiply age by erosion rate to get amount of sediment.
The amount of sediment on the ocean floor is not surprising or unexpected.
Sediments increase in thickness from near zero at the mid-Atlantic ridge,
to several million years' worth near America and Europe. This data supports
plate tectonics, but not a ten thousand year old earth.
Rocks older than the "average" age are protected by having younger
(not "harder") rocks deposited on top of them. The 'column clearly shows
periods of deposition alternated with periods of erosion (recall recent
talk.origins discussions on the Grand Canyon).
The "recent creation" model does not explain the sediment pattern
on the ocean floor, nor the accumulation of the geologic column. The
"erosion/accretion" model nicely explains many geologic features.
# 5.Radiogenic helium in the atmosphere
There are at least two processes working against this method:
1. Escape of Helium by temperature-induced velocity.
2. Escape of Helium by photoionization and magnetic field interactions.
Cook has messed up the thermodynamics somehow, for proper calculations
show that process (1) accounts for the escape of 50% of the [3]He and
2% of [4]He from the atmosphere (percentages are of rate of production).
I'm not surprised; Cook has screwed up calculations like this before.
The rate for process (2) depends on the strength of the magnetic
field of the earth, but calculations referenced in Dalrymple's paper show
an escape rate which balances the production rate. Although process (2)
is complex and not well understood, it shows that there is reason to
suspect that the system is at equilibrium and therefore no actual upper
limit for the age of the earth may be derived from it.
# 6. Polonium halos
I'm not sure why Bob included these, for they really have nothing at all
to do with "dating." Gentry claims they are evidence for instantaneous
formation, but the halos don't tell *when*. In addition, Gentry's halos
are found in "flood deposits," rather than "originally created rocks."
Finally, there are natural explanations which can account for the
halos as not being radiation-induced. There are halos whose size does not
correspond to any alpha-particle energy. Even those proposing instantaneous
creation will have to appeal to natural processes to explain the odd-sized
halos. Is it "simpler" to posit a separate explanation for the "Po" ones?
# 7. Human population growth
Many species have had their populations measured over time. While the
short-term growth rate can vary wildly (due to environmental factors), the
long-term growth rate is always very close to zero. Usually a limited
food supply keeps populations at equilibrium. Until humans invented
agriculture (which breaks that constraint), there is reason to expect that
we were subject to the same limiting forces as other animals. Still,
let's check the implications of Bob's 6000 years @ 0.36% growth:
Start with 2 people at 4000 BC. By 2500 BC, the population is 440. Let's
place half the earth's population in Egypt, and discount the elderly,
women, and children. The Great Pyramid must have been built by about 40
men, who quarried and moved 2,300,000 blocks (up to 50 tons in weight) in
under 40 years' time. (4 blocks/man-day. Must be non-union labor.)
About 20 men must have built the first pyramid some 200 years
earlier, while the other 20 able-bodied men on Earth were constructing
fortified cities in Mesopotamia. In 3700 BC, *both* able-bodied men
on Earth must have been quite busy constructing impressive civilizations
in Crete, Mesopotamia, the Indus River valley, and other sites.
Obviously, Bob's uniform approximation doesn't work. To account
for the population in 3700 BC, he will have to drop his rate to 0.16%. The
rate from 3700 BC to 1 AD will be about 0.06%. Bob will have to admit to a
rate over 2/3 of recorded history that is 96% of the way to equilibrium from
the measured 1971-1975 values. I don't understand how he can find
equilibrium to be "unjustified" when he is suggesting rates about the same
distance from the measured ones for his own scenario.
The growth rate is known to vary greatly over short periods of time; it is
noticeably influenced by factors missing from Bob's oversimplification; and
it is not that far from equilibrium. Bob should have known this method was
unreliable when he plugged in current growth rates and "proved" Last
Wednesdayism. I don't understand why he felt justified in pulling a lower
rate out of a hat; I'd have discarded the method as unreliable.
Bob thought this method wouldn't support long histories when
applied to other creatures. I approximated houseflies, and calculated
their origin to be in 1982 with similar growth rates (probably too low).
Bacteria must have been created no earlier than 1988. Clearly, these
"simple" assumptions can *vastly* underestimate how long a species has
been around. The claim that it does so for humans as well is reasonable.
-------
In summary, recall the results of my examination of the dating methods:
The first five "process-based" methods ignored processes known to operate
in the opposite direction. Bob's simplified "recent creation" model cannot
account for many features easily explained by interaction between these
processes and the reverse ones. We don't *know* these processes to be at
equilibrium, but that is certainly within range of measurement uncertainty.
The halos are something of a mystery, but they are just as much a
mystery to the creationists who must account for Polonium in The Flood.
The final method, population growth, is to me an example of the worst of
creationist dating methods. It depends on an unjustified over-simplified
extrapolation on a rate which is known to vary significantly.
None of the methods are similar to the quantitative methods I
proposed which give an old age for the earth. I again request Bob to
present a definite age (as in, "X years") and tell me how he derived it.
Bales Closing Remarks =========================================================
===============================================================================
To start: Chris asked that I give a definite date for the earth. Because of
the nature of the evidence, I can't. The lower limit is the length of
recorded history. The upper limit, for most of the indications I cited is
less than 50,000 years.
Chris's general objection to my methods is that there are processes
operating in the opposite direction, at least theoretically. I pointed out
most of these in my opening statement. The point is, however, that it is
not known whether these processes do explain the data. Chris admits this
by saying that the processes are "not well understood, or not likely
uniform, or not measured accurately (yet)." In other words, the evidence to
say whether or not my statements are wrong is not there. So Chris's statements
that the young earth position is wrong, and furthermore that the major
proponents of a young earth know they are wrong, are not supported by that
evidence.
The same standard must apply to all evidence. Chris says that if there were
a process that turned uranium to lead at a significant rate that I would be
justified in ignoring uranium-lead dates. There is not such a process, but
there are known processes that influence the accuracy of such dates. And one
of the main methods which Chris uses to date the earth, when applied to
samples of known ages, has been in error by as much as seven orders of
magnitude. Thus, while I do no say to ignore the dates, in the sense of
not talking about them, I feel that I am justified in not treating them as
established fact.
On to some of Chris's specific objections. The length of this statement
prevents me from dealing with them all. I pointed out most of the processes
to which Chris refers in my opening statement. I also pointed out why they
are not good explanations.
>The comet capture model is a better explanation than recent creation as
>recent creation "in situ" cannot account for the "youth" of s-p comets.
The average lifetime of a short period comet has been calculated as about
500 years. If all comets were created as they are, this figure is
obviously low. Adjusting it by a factor of 40 would lead to the presence
of short-period comets up to 20,000 years after creation. One researcher
into the theory Chris calls "better" would have to adjust his results by
a factor of *40,000* to get agreement with what we see.
In carbon-14 dating, Chris seems to restrict the carbon-14 concentration to
start near equilibrium and says that the creation model does not account
for dates older than 10,000 years. But immediately after creation, there
may very well have been little carbon 14. Material from that time,
whenever it was, would date quite old, if the dating assumed near-equilibrium
conditions.
The main point of the "erosion rate of the continents" appears to have been
missed. Methods of moving sediment off of the ocean floor do not answer the
problem, since they do not increase the age of continental rocks. However
old the earth is, the average age of continental rocks should be less than
the time it would take to wear down the continents. And, contrary to Chris's
claim, younger rocks which are not harder will not protect old rocks,
since there is time in the standard chronology for both the "protecting"
and "original" rocks to have worn away many times.
Chris claims that Melvin Cook's calculations of He escape are wrong. I would
like to see a reference to the "proper" calculations, so as to judge if the
claim is correct. I point out, however, that in the 10 months following
the publication of the data, no one pointed out the alleged error of
orders of magnitude.
Chris attempts to show my growth projections are off by using the average
rate to get very low populations in the past. However, there is no reason
to assume the rate is constant; history shows it isn't. Chris apparently
guessed on the rates of housefly population growth. Unless there is some
evidence to support the figure used, the fact that the calculation gave
ridiculous dates shows nothing about my calculations. Also stated is that
is reasonable to believe that the human population is near equilibrium.
However, this is not what we see now. The point, as in the case of comets,
is that only small adjustments are needed in the simple young earth model to
obtain agreement with observed data, while adjustments orders of magnitude
greater are needed in the simple old earth model. Thus, I disagree with
the claim that the latter model is better (in these cases.)
Finally, Chris says that the methods yielding old ages are more quantitative
and different than those yielding young ages. I disagree. Measurements
can give quantitative figures for the amount of isotopes in a rock. But
going from those figures to the age of the rock is, as I showed in my
rebuttal statement, subject to the same number of errors and assumptions
as are the methods I propose.
To close, I'll restate what I'm trying to show:
There is evidence that points to a recent origin for the earth, as well
as evidence that points to an ancient origin. For each class of
evidence, there are alternate explanations that interpret it in
terms of the alternate view. We do not know for certain which view
is correct. I cannot prove the young earth theory; I can only show
that it is consistent with the evidence.
While I present the young earth theory as as possibility, to be considered
along with the old earth theory, Chris presents the old earth theory as the
only possibility to be considered. In support, I have needed to -- and I
have -- presented indications of a young earth and alternate explanations
for contrary evidence. Chris, by contrast, has needed to show not only the
corresponding indications and explanations for an old earth -- which has been
done -- but also to show that they are correct -- which has not been.
===============================================================================
===============================================================================
--
Chris Stassen stassen@netcom.UUCP
From stassen Fri Jun 1 07:56:10 PDT 1990
Article: 4523 of talk.origins
Path: netcom!stassen
From: stassen@netcom.UUCP (Chris Stassen)
Newsgroups: talk.origins
Subject: Re: Bales vs. Stassen, "Age of the earth", 2 of 2
Message-ID: <12724@netcom.UUCP>
Date: 1 Jun 90 14:55:42 GMT
References: <12723@netcom.UUCP>
Reply-To: stassen@netcom.UUCP (Chris Stassen)
Organization: The Lion's Den, San Jose
Lines: 727
Summary:
This is the second of two postings generated by the debate. It contains
my opening statement, Bob's rebuttal, and my closing remarks.
(The cross-in-the-mail format for the debate caused this division to make
the most sense; the debate wouldn't fit in a single article anyway.)
Stassen Opening Statement =====================================================
===============================================================================
One quick announcement: I have heavily used Dr. Dalrymple's paper here (USGS
Open-File Report 86-110). I have permission to copy and distribute it, so
Email me your postal address if you want a copy ($5 for copying and postage).
You can also order it from the Government Printing Office for $14.
I am rather pleased and quite surprised that Bob Bales agreed to this debate.
Not many "scientific" creationists would be willing to do so.
In 1986, the International Conference on Creationism set up a debate
between Ken Miller and Duane Gish. At Miller's suggestion, the organizers
agreed that the topic was to be the age of the earth. Gish *refused to debate
that topic* (even though at a creation conference, he would have had a
favorable audience), and demanded it be changed. Miller refused to agree to a
change of the agreed topic, and was "disinvited" from participation in favor
of someone willing to deal with Gish's standard presentation. Perhaps Bob and
I will discover whether or not Gish's fear of the subject is warranted.
The remainder of my opening statement will be divided up into:
(A) Methods creationists use to give an age for the earth
(B) Methods scientists use to give an age for the earth
(C) Creationist criticisms of radiometric dating
-----------
(A) Methods creationists use to give an age for the earth
"Scientific" creationists already "know" the age of the earth and it is not
from the evidence. Henry Morris - "the father of scientific creationism" -
admits that Genesis takes precedence over the evidence, as he says:
"No geological difficulties, real or imagined, can be allowed to take
precedence over the clear statements and necessary inferences of
Scripture." (_Biblical Cosmology_, quoted in _Science and Creationism_)
It would have been nice to talk about several "dating" methods which Bob has
discussed that give a young age for the earth. Unfortunately, Bob has only
ever mentioned one method in talk.origins, and that was several years ago.
Perhaps I will have more methods to talk about in my rebuttal, but I will
begin by discussing Bob's only publicly proposed method (to date).
In 1965, _Chemical Oceanography_ published a list of some metals' "residency
times" in the ocean. This calculation was performed by dividing the amount
of various metals in the oceans by the rate at which rivers bring the metals
into the oceans.
In late 1986 Bob posted <610@tekfdi.UUCP> to talk.origins, claiming
that these numbers gave "upper limits" for the age of the oceans (therefore
the earth) because the numbers represented the amount of time that it would
take for the oceans to "fill up" to their present level of these various
metals from zero. (It was one of Bob's first postings to the group.)
First, let us examine the results of this "dating method." The book
that Bob was probably using only lists some of the results. The following
list is more complete (residency times, in years):
Al - 100 Pb - 2k Ba - 84k Ag - 2.1M
Fe - 140 Si - 8k Sn - 100k K - 11M
Ti - 160 Ni - 9k Zn - 180k Sr - 19M
Cr - 350 Co - 18k Rb - 270k Li - 20M
Th - 350 Hg - 42k Sb - 350k Mg - 45M
W - 1000 Bi - 45k Mo - 500k Na - 260M
Mn - 1400 Cu - 50k Au - 560k
Now, let us critically examine this method as a method of finding an age for
the earth. There are many problems which I would like to hear Bob address
(or alternately, he can concede the method's lack of merit):
1. The method ignores known mechanisms which remove metals from the oceans:
a) Many of the listed metals are in fact *known* to be at equilibrium;
that is, the rates for their entering and leaving the ocean are the
same. One cannot derive a date from a process at equilibrium. (It
could go on forever without changing concentration of the ocean.)
b) Even the metals which are not known to be at equilibrium are known
to be very close to it. I have seen a similar calculation on
uranium, failing to note that the uncertainty in the efflux estimate
is larger than its distance from equilibrium. To calculate a *true*
upper limit, we must calculate the *maximum* upper limit, using all
values at the appropriate extreme of their measurement uncertainty.
We must perform the calculations on the highest possible efflux rate,
and the lowest possible influx rate (within the measurement error).
If that gets us to equilibrium, then no upper limit can be derived.
c) In addition, *even if* we knew exactly the rates at which metals were
removed from the oceans, and *even if* these rates did not match the
influx rates, Bob's numbers are still wrong. It would probably require
solving a differential equation, and any reasonable approximation MUST
"figure in" the efflux rate. Bob missed this factor entirely. Bob's
published values are only "upper limits" when the efflux rate is zero
(which is known to be false for all the metals). Any efflux decreases
the rate at which the metals build up, invalidating the alleged "limit."
2. The method simply does not work. Ignoring the three problems above, the
results are scattered randomly (5 < 1k years, 5 in 1k-9k years, 5 in 10k-
99k years, 6 in 100k-999k years, 6 > 1M years). Also, the only two results
that agree are 350 years, and Aluminum gives 100 years. If this is a valid
method, then the Last Wednesdayists have just won this debate by proxy.
3. These "dating methods" do not actually date anything, which prevents
independent confirmation. (Is a 19M year "limit" [Sr] a confirmation
of a 42k year "limit" [Hg]? No!) We will see later that independent
confirmation is very important. Scientists try to date objects or
events, by multiple means. They do not accept a date with confidence
unless more than one independent method confirms it.
4. These methods depend on uniformity of a process which is almost certainly
not uniform. There is no reason to believe that these rates have been
constant throughout time. I would expect that man, by mining metals
and bringing them to the surface, has added noticeably to the amount
of metals which are "in the loop."
5. There is no "check" built into these methods. There is no way to tell
if the calculated result is good or not. We will later see that the best
methods used by geologists to perform dating have a built-in check which
identifies undateable samples. The only way Bob can "tell" which of
these methods produce bad values is to throw out the results that he
doesn't like. He would do this by comparing them to another age arrived
at by other means (which he has never talked about in talk.origins).
If Bob wishes to present a "dating method," he should instead be
presenting the "other means" by which he arrived at a judging date for
this method's accuracy.
Clearly, Bob's one method is neither convincing nor reliable. One might
wonder why he found it worthy of publishing. Yet Bob is not alone in this.
There are many creationists who have published this method. In my own
library, *every* creationist text which provides evidence for a young earth
uses this argument. Here are the more popular ones from that set:
Henry Morris, _Scientific Creationism_, 1974; pp. 153-6
Walter T. Brown, _In The Beginning_, 1989; p. 16
R. L. Wysong, _Creation-Evolution_, 1976; pp. 162, 163
Morris & Parker, _What Is Creation Science?_, 1987; pp. 283-4, 290-1
Obviously, these are a pretty popular set of "dating" mechanisms. A curious
and unbiased observer could quite reasonably refuse to even listen to the
creationists until they "clean house" and stop pushing nonsense arguments.
If I found "Piltdown Man" in a modern biology text as evidence for
human evolution, I'd throw the book away. (If I applied the same standards
to creationist materials that I own, I wouldn't have any left.)
-----------
(B) Methods scientists use to give an age for the earth/universe.
I will present three ways to derive an age for the earth:
1. We can try to find the oldest rocks on the earth. While this doesn't
guarantee an absolute age (for the original rocks need not be available),
it can at least give a lower limit for the age of the earth. (Unlike
Bob's limits, these are derived by dating a specific object.)
The oldest rocks exposed on the surface of the earth are 3.5 to 3.8
billion years in age. Consider the various dating methods applied to the
Greenland Amsitoq Gneiss:
Rb-Sr isochron 3.70 +- 0.14 billion years
Pb-Pb isochron 3.80 +- 0.12 billion years
U-Pb discordia 3.65 +- 0.05 billion years
Th-Pb discordia 3.65 +- 0.08 billion years
Lu-Hf isochron 3.55 +- 0.22 billion years
Note that all of the methods agree (3.68-3.70 is within all of their
ranges of error). Isochron and discordia methods also have an internal
check which identifies undateable samples. Similar formations which
give similar ages can be found as well in North America, India, Russia,
Australia, and Africa. This date therefore merits some confidence.
If Bob wishes to object to these dates, he will have to explain
why a 10,000-year-old rock was "created" so that five independent dating
methods would all yield the same fictitious age.
2. We can try to date other objects in the solar system. Both sides of the
debate believe that other objects in the solar system formed at about the
same time as the earth, and therefore an age for one of those objects is
an age for the earth.
The moon is not as geologically active (dating should be more reliable,
as rocks have less complex "histories"). Again, the original rocks need
not be available, so the age will only be a lower limit; the moon must be
at least as old as the oldest rocks we've found on it.
Lunar basalts were collected by six different Apollo expeditions,
from six different sites. These samples all give ages ranging from 3.16 to
3.96 billion years, by both Rb-Sr isochron and Ar-Ar dating methods. When
both methods are applied to one sample, the results agree to within 3%.
Meteorites are not geologically active at all; there is good reason to
expect that most are undisturbed since their formation with the rest of
the solar system. Faure has a chapter on meteorite dating in _Principles
of Isotope Geology_ (this book is a *must-read* for anyone who wishes to
understand radiometric dating).
Chondritic meteorites consistently give an Rb-Sr isochron age of
4.49 +- 0.07 billion years. Achondritic meteorites consistently give
an Rb-Sr isochron age of 4.36 +- 0.11 billion years. A combined method
using samples of minerals from many different meteorites gives an Rb-Sr
isochron age of 4.46 +- 0.08 billion years.
Note that a small percentage of meteorites give ages younger than
4.5 billion years. This is to be expected when events such as collisions
cause melting and recrystallization, which would "reset" the radiometric
"clocks." Still, most meteorites give the same age, and none give ages
older than that.
This arrangement of data is expected if the solar system is indeed
4.5 billion years old. I can't imagine how to explain it if the actual
age is 10,000 years. But that is Bob's task - not mine.
Again, if Bob wishes to disagree with the methods, he will have to give
specific objections. He will have to explain why meteorites were created
to give isochron ages of 4.5 billion years rather than, say, 91 billion
years. He ought to have a reason why a 10,000-year-old sample could be
expected to give an isochron at all.
3. Finally, since we figure all of the objects in the solar system formed
at about the same time (as do the creationists), we can construct a
"model lead" age. This is a calculation which is performed on various
Pb isotopes (some of which are the result of uranium decay, and others
which are not). We will plot [207]Pb/[204]Pb vs. [206]Pb/[204]Pb of
samples from several different objects (meteorites and earth sites).
If these objects were all formed at the same time from a shared
pool of materials, these points should lie on a straight line, and the
slope of the line should give the age at which these objects became
separated.
If these objects instead had separate origins (for example if
they were created out of nothing), then there is no reason to expect the
data points to lie on a straight line. Since the age is determined
from the slope of the line, a scattering of points prevents any age
from being determined at all.
In addition, if some of the samples were contaminated after the
separation event, then those points should be moved away from the
straight line, and again a meaningful age could not be determined. The
fact that the samples do indeed lie on a straight line provides evidence
that the resulting date is accurate, and that the samples have not been
contaminated.
Below is my best ASCII attempt at drawing the diagram:
+---------------------------------------------------------------------+
| 7 |
| |
30 + |
| |
| 6 |
| |
| |
20 + |
| |
| 4 5 |
| 3 |
| 2 |
10 + 1 |
| |
| |
+------+------+------+------+------+------+------+------+------+------+
10 20 30 40 50
Y-axis: ratio of Pb[207]/Pb[204]; X-axis: ratio of Pb[206]/Pb[204]. Data
points: (1) Iron Meteorites; (2) Beardsley; (3) Modern sediments and young
Galenas; (4) Saratov; (5) Elenovka; (6) Richardton; (7) Nuevo Laredo.
I can't really do it justice in ASCII, I recommend interested parties to
get the original. All of the points lie on (or very near) a straight line.
The slope of the line represents an age of 4.55 billion years. The only
reasonable explanation for this arrangement of the data is that (1) the
objects in the solar system all formed from a common pool of matter, and
(2) they became isolated from each other about 4.55 billion years ago.
I doubt Bob has a convincing explanation for how young, "independently
created" objects from all over the solar system could have their lead
contents form an isochron. I wonder how he will account for the fact
that the resulting age matches other dating methods' results for the
solar system.
-----------
(C) Creationist criticisms of the scientific methods.
I would like to deal with Bob's objections to methods which give an old age
for the earth. However, he has not yet given any which are specific enough
to examine in detail. The objections Bob posts in talk.origins usually amount
to asking, "but how do you KNOW it gives the right age?" This "objection"
does not attempt to explain how the methods could be in error, and therefore
is not open to examination. Bob will have to do better than that here.
Luckily, there is no shortage of creationist criticisms of
radiometric dating methods. Bob will have some big-name stand-ins until
rebuttal time. The contortions (and distortions) that creationists will go
through in order to discredit radiometric dating are almost amusing:
1. (Slusher) "The radioactivity of carbon-14 is very weak and even with all
of its dubious assumptions the method is not applicable to samples that
supposedly go back 10,000 to 15,000 years."
This was written in 1973. Laboratories were then performing [14]C
dating to either 35,000 years or 50,000 years (the latter required
cosmic ray shielding). Today, new experimental methods can reach
80,000 years, and 100,000 years may soon be reached.
2. (Slusher) "The decay rate of [57]Fe has been changed by up to 3% by
electric fields."
[57]Fe is a stable isotope which does not undergo radioactive decay.
When [57]Fe is produced from the decay of [57]Co (an isotope which
does not occur naturally), there is excess energy remaining in the
nucleus. The nucleus then undergoes an "Internal Conversion" which
releases this energy, but it remains the same isotope. The IC rate
may be changed, but this has no bearing on the types of radioactive
decay used in radiometric dating.
Slusher requires (roughly) a 75,000,000% upward change in decay
rates - on the average - in order to move the dates into his time
scale of 6,000 years. There is no evidence that the decay rates
relevant to radiometric dating can be changed by even 1%. These
decay rates are the same at -186C to 2000C. They are the same in
a vacuum to thousands of atmospheres. They are the same under
varying magnetic and gravitational fields.
3. (Morris) "Another [thing which could change uranium decay rates]
would be the free neutrons discussed above."
The density of free neutrons in nature (even in radioactive ores) is
six orders of magnitude too small to have any effect at all. Such a
large flux of neutrons would be quite noticeable - in more than rocks.
Also, free neutrons do not directly alter decay rates and cannot
produce the same results as uranium's normal alpha or beta decay.
Uranium decays into lead. Lead can capture free neutrons, which
would change U/Pb and Pb/Pb dates. Unfortunately, this process works
in the opposite direction from Morris' needs. The effect would be
very slight and would cause the corupted date to read *younger* than
the actual age of the sample. (Morris claims that the dates read
orders of magnitude *older* than the actual age of the sample.)
4. (Morris) "The so-called 'branching ratio,' which determines the amount
of the decay product that becomes argon (instead of calcium) is unknown
by a factor of up to 50 percent."
It was known to within 5% in 1958. It was known to within "a few"
percent by the time Morris wrote that sentence. It is known to
within a fraction of one percent today.
5. (Moore) "The method involving decay of rubidium 87 into strontium 87
is considered so unreliable that it has been discarded."
Actually, it is one of the most accurate and widely used methods
available. Many of the data points given above for the earth,
moon, and meteorites were calculated by that method.
6. (Kofahl and Segraves) "A series of rocks from Reunion Island in the
Indian Ocean gives K/Ar ages ranging from 100k to 2M years, whereas
U/Pb and Pb/Pb ages range from 2.2b to 4.4b years."
The paper cited by Kofahl and Segraves does not contain any U/Pb or
Pb/Pb ages. It does contain some Pb measurements, but is missing
measurement of one Pb isotope required for U/Pb or Pb/Pb dating.
K & S have apparently decided to perform some calculations of their
own. They have therefore only succeeded in casting doubt upon a
dating method of their own invention. This should be no surprise
to them; dating methods invented by creationists never work. :-)
-----------
Summary:
We have examined Bob's method for dating the earth. The method has many
insurmountable problems, yet it is repeated in several creationist books
which argue for a young earth. We have also examined some creationist
complaints about the validity of the scientific methods for finding an age
for the earth. All are either irrelevant or simply wrong. These are not
the hallmarks of an enterprise which has reached its conclusions on careful
study of the evidence. These are not the hallmarks of an enterprise which
even *understands* the evidence.
Some accuse "scientific" creationists of ignorance or dishonesty.
That may be true in some cases (e.g. Morris trying to palm off wildly
inaccurate dust influx rates as reasonable values). A more reasonable
explanation is that most of these mistakes are born out of desperation to
support a view that the evidence flatly contradicts.
Perhaps Bob can do better than the leaders of the movement. Since
Bob usually seems content to work directly and trustingly from their books,
I do not expect it. Bob may surprise me and produce a reasonably convincing
method which gives a young age for the earth. But if he manages to do so,
it will not be a method found in popular creationist literature.
Bob's age for the earth differs by about six orders of magnitude from the
value that scientists propose. This is not a minor difference. One of our
two positions is like arguing that Alpha Centauri is closer to the Earth than
the Sun is, or that one can buy a nice house in California for a quarter.
The positions are so far apart that it should be trivial to choose the one
that the evidence supports. It is. I have presented some solid pieces of
this evidence. Bob needs to propose some evidence of his own, but he must
also have *testable explanations* for how my evidence fits into his position.
Bob will have to offer an explanation for how a collection of young
rocks from different parts of the solar system could form an isochron giving
an age of 4.5 billion years. He will also have to offer an explanation for
how the Amsitoq Gneiss could give the same (incorrect) date by 5 independent
methods, all of which passed internal checks.
No matter how many "rocks" Bob throws at radiometric dating, he will
need to present an explanation for the curious agreement of all of the varying
methods. Proposing a deceptive creator is an admission of failure to do so.
In short, the "scientific" creationists are simply wrong about the age of the
earth; the leaders of the movement KNOW IT (even if Bob doesn't). In their
books, a young earth is treated as if it were an obvious conclusion from the
evidence. In a debate, Duane Gish refuses to discuss it. Gish KNOWS that a
young earth is no more supported than a flat earth. He can't afford to be
destroyed in a debate, so he cannot afford to discuss the age of the earth.
I am impressed with Bob's faith in his position, venturing where
the leaders of his movement fear to tread. I also believe that Bob is
quite honest about his beliefs (though the evidence stands against him).
I don't expect to convert Bob; he was sure of his position long before he
studied the evidence for the alternative. But if he is convinced to obtain
and read the Dalrymple paper, I will consider this debate to be a success.
Bales Rebuttal ================================================================
===============================================================================
Chris contrasts:
>(A) Methods creationists use to give an age for the earth
>(B) Methods scientists use to give an age for the earth
I must protest what appears to me to be an attampt to "prejudice the jury."
As I see it, this is supposed to be a debate on the scientific evidence on
the age of the earth. All arguments used by both sides should fall into (B).
Furthermore, the implication is that young-earth dates (which is what I
suspect Chris means, although not all creationists believe in a young earth)
are distinct from scientific methods. That this is false is shown by Chris's
claims that creationists misinterpret or misuse scientific data. An age based
on misinterpretation of data is still a *scientific* claim.
>"Scientific" creationists already "know" the age of the earth and it is not
>from the evidence.
But what creationists know or don't know has no bearing on what the evidence
shows. Many creationists do believe for reasons in addition to the physical
evidence that the earth is young. Those reasons do not provide scientific
support for my position, so I do not use them here. However, neither do they
provide support for Chris's position, so they add nothing to the debate.
>It would have been nice to talk about several "dating" methods which Bob has
>discussed that give a young age for the earth. Unfortunately, Bob has only
>ever mentioned one method in talk.origins, and that was several years ago.
What follows is a discussion of age determination from looking at the
amount of metal dissolved in ocean water. Note that (although Chris
obviously did not know this) I did not use this method in my statement.
Objections similiar to those raised here were raised when I first proposed
the method. It appears to me that the objections may be valid. I don't think
the method is worthless, as Chris seems to believe, but I need to study it
more in order to defend it.
Turning to the methods Chris uses:
>1. We can try to find the oldest rocks on the earth. While this doesn't
>guarantee an absolute age (for the original rocks need not be available),
>it can at least give a lower limit for the age of the earth.
>The oldest rocks exposed on the surface of the earth are 3.5 to 3.8 billion
>years in age.
Rocks are not stamped "age: 3 billion years." The dates are found indirectly,
in this case, by measuring the radioactive isotopes in the rock.
As I have pointed out before, there are cases in which 3-billion year "dates"
found by similar radioactive measures corresponded to an actual age of less
than 200 years.
Whenever I mention this example, I am greeted with a storm of "misuse"
cries. *But consider exactly what I am saying.* I am saying that the
results measured on the Hawaiian rocks indicate a 3 billion year radioactive
date does not necessarily correspond to a 3 billion year actual date. This
is not a misuse.
There is one other response I'd like to comment on. The claim was made that,
since the rocks were predicted to give inaccurate dates, the case has no
implications for dating. It even seemed to be implied that since this
prediction was true, predictions of accuracy will be true also. But this
is not the case. In order to be judged accurate, a method must show
accuracy. Inaccuracies of 6-7 orders of magnitude, however predicted or
however explained, do nothing whatsoever to support an accuracy claim.
Consider the situation as follows: We have two rock samples, which both give
radioactive dates in excess of 3 billion years. For one sample, we know
the date independently. For the other, we don't. If the known sample is
less than 200 years old, why should I believe the unknown sample is in
excess of 3 billion? Chris gives one answer, which I will address below.
>Consider the various dating methods applied to the Greenland Amsitoq Gneiss:
[Chris gives 5 dates.]
>Note that all of the methods agree (3.68-3.70 is within all of their ranges
>of error).
The "ranges of error" are not that, but are ranges of uncertainty, given that
the basic assumptions which went into the dating are correct. If the
assumptions are not right, the error range shown is not the actual error.
>Isochron and discordia methods also have an internal check which identifies
>undateable samples.
Having multiple points which should, and do, fall on a line (in the case
of isochrons) increases confidence in the date, but does not establish it to
be correct. If the theory behind the derivation of the isochron is not
correct, the points can lie anywhere, including on a line. It might be
argued that points would be very unlikely to form a line if the theory was
wrong. This may very well be true -- as I said, the internal checks do
support the theory. But I would be interested in a probability estimate.
In this paragraph, I am asking a question, not raising a definite objection.
As I will describe below, there are a number of things which can influence
radiometric dating, and a number of corrections which may be made. What
corrections, if any, were made to arrive at the results given, and what
effect might that have on the points' lining up?
>Similar formations which give similar ages can be found as well in North
>America, India, Russia, Australia, and Africa. This date therefore merits
>some confidence.
Accuracy implies consistancy, but consistancy does not imply accurracy. If,
for example, dates obtained from one formation are inaccurate, dates obtained
from similiar formations might also be expected to be similarly inaccurate.
>If Bob wishes to object to these dates, he will have to explain why a
>10,000-year-old rock was "created" so that five independent dating
>methods would all yield the same fictitious age.
There are two possible meanings of "why." If Chris is asking why there
might be a reason to believe the dates are wrong, the answer lies in
the evidence mentioned above and to be discussed below. If, on the other
hand, the question is why a Creator would "fool" us, I see the answer as not
being difficult: There is no evidence of fooling. The Creator did not
instruct us in which dating methods to use. Those who do the dating are
totally responsible for developing the methods and interpreting the
results. If the dates are wrong, it is because the the evidence was
misinterpreted, not because it is deceptive.
Chris mentions other datintg methods: dating objects in the solar system and
construct a lead isochron from readings on various materials. These methods
use the same basic principles as the radioactive dating of materials on earth.
I take it, then, that Chris claims radioactive dating is the method which
leads to the conclusion of an old earth.
Which leads to the question: Are radioactive dating methods accurate? Or
are there know problems with them. When in the discussion of the incorrect
Hawaiian dates, I claimed that the history of the rock could affect the dates,
I was severely criticized. In research for this debate, I found out I was
more right than I knew. (Chris discussed some creationist criticisms of
radioactive dating. Since they are not the criticism I use below, I'll let
threm lie.)
I don't have an exact quote, but in _Mammal-Like Reptiles and the Origin of
Mammals_ (1982), T.S. Kemmp refers to the known problems of uranium dating.
However, I wish to discuss mainly Potassium-Argon dating. This is one of the
most often used methots, and in this group it has been referred to as the
most accurate radioactive method. My reference for this is _Radioactivity in
Geology: Principles and Applications_, by Eric Durrance of the University of
Exeter. Based on its references, it was published in 1980 or later.
Quoting: "Thirdly, to obtain the age of formation of a rock or mineral, the
material must have remained a close chemical system since its formation, with
neither gain nor loss of radioactive parent or daughter atoms. . . .
Unfortunately, geologic materials and environments do not often
meet this requirement. In decay schemes in which gaseous daughters are
produced, such as. . .[Potassium-Argon and Uranium-Lead]. . .for example,
the loss of the daughter by diffusion, even through compact materials, can
be considerable." (page 287)
The book goes on to discuss methods by which inaccuracies can occur: material
movement caused by groundwater, identity of daughter products with non-
decay isotopes in the rock, the proportion of total potassium which is
radioactive or contamination by atmospheric argon when the rock was formed,
when the sample was prepared, or when the measurement was made.
Argon can also be lost from a rock by diffusion as the sample is heated
(with the degree depending on the mineral making up the rock, and the
lattice defects in the crystal), through weathering, as a result of the
physical processes involved in collecting and measuring the sample, and
a result of damage to crystal structure due to radiation from nearby
sources. Argon can enter a rock at or after the time of formation.
With all of these possible sources of errror, the often-heard statement
that "radioactive dating is acccurate since decay rates are constant" does
not tell the entire story, or even a major portion of it. To be fair, the
book I reference mentions that there are corrections for some of these
factors. But if the errors are not recognized in some cases, the
corrections will not be done. Also, the corrections require assumptions of
what happened and how to correct.
I cannot prove that the old dates are wrong. But since there are
uncertainties in the dates, both theoretical and actual, as evidenced by
mate 7 orders of magnitude in error, I contend that those who believe in an
old earth cannot know the dates are right. It has never been shown that a
3-billion date from these methods has been right. But it has been shown that
such a date has been wrong.
Chris closes with a number of comments, a few of which are:
>Bob's age for the earth differs by about six orders of magnitude from the
>value that scientists propose.
The range of dates I use differs from the more commonally accepted dates.
*However, since it is derived by scientists from scientific evidence, it
differs NOT AT ALL from a value proposed by scientists.* The young earth
date is, as I showed in my first statement, derived from the same type of
observations by the same deductive processes as is the old earth date. The
former is as "scientific" as the latter. Why then claim that it isn't? I
can't judge motive, I can only judge effect. Most people, myself included,
will say that a scientific date is better than a non-scientific one. Thus,
if one date is not-scientific, it can be discarded *before examination.*
It's thus easier to ignore whether or not it meets the evidence.
>In short, the "scientific" creationists are simply wrong about the age of the
>earth; the leaders of the movement KNOW IT (even if Bob doesn't).
We are still in a discussion of whether my quoting of someone's statement
implied that he personally believe the view the statement supports. But
here, Chris says what people *know* without quoting them. If the claim
cannot be supported by what they have said, I think it should be withdrawn.
Stassen Closing Remarks =======================================================
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Three quick points before I dive in:
(1) It seems Bob is unhappy that I divided opinions into "scientists" versus
"creationists." I chose "scientists" because I *am* presenting the view
held by mainstream science, and "evolutionists" has no applicability to
categorization of geologists (except in the minds of conspiracy-theorists).
(2) Bob dismisses my Morris quote by saying that creationists have reasons
"other than the evidence" to believe the Earth is young. Bob is badly
misreading Morris' statement, for Morris says that Genesis is reason to
believe in a young Earth *in spite of* the evidence (not "in addition to").
It "adds to the debate" because it explains why the evidence is only of
secondary importance - even to "scientific" creationists. Does Bob agree?
(3) I already use Gish's actions (refusal of ICC debate and generic debate
disclaimer) to support my claim that he knows the evidence does not support
a young Earth. I don't see a need to produce a quote, too. If Bob can
come up with a plausible alternate explanation for why Gish would betray
his sworn position and his organization's position, I will reconsider.
In my opening statement, the dating methods I used were all radiometric. I
used radiometric dating because it is the only *quantitative* method I know
for giving an age. There are plenty of geological formations which I could
discuss (e.g. varves, fossil reefs and stromatolites, limestone and chalk
deposits) that are very difficult to explain as features of a young Earth.
I mentioned a few in my rebuttal (e.g. ocean floor sediments). But these
formations cannot be used to date the entire earth - which is our topic.
I am somewhat disappointed that Bob didn't provide better objections to the
radiometric dating methods. He mostly reused materials that he had posted
previously to talk.origins. (I was loaded for bear, but faced gnats. :-) )
I presented only isochron and discordia methods. Bob gave objections
to K-Ar methods, which he incorrectly generalized to all methods. For K-Ar
dating methods, there is an "assumption that no parent or daughter product has
entered or left the system" (technically, the assumption is that it won't
happen without leaving detectable evidence of contamination). There is no
analogous assumption for isochron methods, as a systematic contamination is
the only *reasonable* explanation for a bad date which keeps the points on a
line. That sort of contamination ("the mixing model") is detectable, was
tested for, and was found *not* to be present.
Bob makes the claim that "radiometric dating methods are known to
give very inaccurate (6-7 orders of magnitude) results." But this is in a
tiny minority of cases. If these methods are so wildly inaccurate, how do
five of them agree on the same age? If the five methods gave results similar
to the metals-in-the-oceans method (scattered randomly), I would be first in
line to call the Amsitoq Gneiss sample "undateable." (By the way, I presented
the "raw" results of the methods; no "corrections" necessary.)
Bob also objects that the dates "have never been shown to be correct."
They show a *strong* correlation with each other, with position in the geologic
column, and with dates derived by other means. The methods work practically
all the time on samples of known ("historical") age which pass contamination
tests. I don't know what more Bob expects. He argues we can't "know" the age,
but lack of absolute certainty doesn't make 10k years a palatable alternative.
(Bob would need to explain how the dates could *consistently* be so far out of
whack. Without that explanation, such an argument is worthless.)
I also want to take issue with Bob's argument against deceptive
creation, which was to say that "the Creator didn't design the dating methods."
All radiometric dating methods I presented are straightforward mathematical
equations derived directly from half-life and isotope measurements (yes, even
isochron methods). Agreement of the five methods is "appearance of age" just
as surely as if the rock were labeled "3.7 billion years old" (perhaps even
*more* surely, as a label is easier to fake). Bob pleads "misinterpretation,"
but fails to present any intepretation at all which could account for the
sample's actual age being nearly six orders of magnitude lower.
Bob is asking me to believe that the Creator (without deception - by accident?)
"initialized" or an unidentified process (acting for <10,000 years) "changed"
isotope levels in the Amsitoq Gneiss so that five self-checking methods would
yield the same (wrong) age. If this is creationist "science," it's unteachable
in public schools even without religious reference. Arguments like that would
*justifiably* get laughed out of any respectable refereed journal. But one
can find lots of arguments like that in creationist "scientific" journals. :-(
An old earth provides the best and simplest explanation for the Amsitoq
Gneiss dates, the Solar System model Lead results, the pattern of ocean-floor
sediments, and the youth of short-period comets (see my rebuttal for the last
two). A 10,000-year-old earth does not explain any of these things easily.
[Note that I can use Bob's own evidence to contradict his proposed age!]
If the Earth were young, and the Creator wanted us to believe it, then
all five methods applied to the Amsitoq Gneiss would give an age of 10k years.
Anyone examining the evidence independent of religious conviction cannot escape
the conclusion that the Earth is very old (Harold Coffin, a creationist witness
at the Arkansas trial, admitted that under cross-examination).
In summary, Bob dismisses radiometric dates mainly "because they are not known
to be correct." This argument holds no water because he failed to explain
how the dates could *systematically* be wrong. It is merely a naked handwave,
without any "scientific" hypothesized mechanism to support it.
Furthermore, this dismissal (on the grounds of "lack of certainty")
implies that Bob's belief in a young earth is based on something which will
override "non-certain" - but solid - evidence. I wish Bob had discussed
whatever it is he finds so convincing. His seven dating methods certainly
don't merit such an investment of confidence; I bet he would still believe in
a young Earth even if he were forced to admit his methods to be unreliable.
Bob has apparently neglected to present *critical* (to him) reasons
why he believes in a young Earth. Why waste time with extremely low-quality
dating methods or weak hand-waving dismissals of radiometric dating? Why
didn't Bob "bring out the big guns" and discuss the most convincing and
important (to him) reasons/evidence for belief in a young Earth?
I thank Bob for participating; I have enjoyed myself. I can't help but feel
that Bob didn't make his strongest case here, and I hope that someday he will
make up for that in talk.origins. Speaking of talk.origins, I'd like to hear
from anyone who managed to read this far; get in touch with me by Email.
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E-Mail Fredric L. Rice / The Skeptic Tank