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Author Topic:   calling REAL scientists
abee
Inactive Junior Member


Message 1 of 11 (88297)
02-24-2004 2:31 AM


A YEC sent me this. It seems dead dodgy to me. However, I do NOT pretend to be a scientist, although I do believe in evolution. Any comments???

Radiometric Dating - The Assumptions
Many of the ages derived by radiometric dating techniques are highly
publicized. Nevertheless, the fundamental assumptions employed are not.
Here are the three major assumptions for your consideration:
1. The rate of decay remains constant.
2. There has been no contamination (that is, no daughter or
intermediate elements have been introduced or leeched from the specimen
of rock).
3. We can determine how much daughter there was to begin with (if
we assume there was no daughter to begin with, yet there was daughter at
the formation of the rock, the rock would have a superficial appearance
of age).
Are these foundational assumptions reasonable? Recent findings seem to
indicate that though we ourselves have not been able to vary the decay
rates by much in the laboratory, the decay rates may have been
accelerated in the unobservable past [1]. If this were the case, the
first assumption would be deemed unreasonable. This would completely
upset our current standardized view of earth's history. Dr Carl Wieland
summarizes the recent findings: "When uranium decays to lead, a
by-product of this process is the formation of helium, a very light,
inert gas which readily escapes from rock. Certain crystals called
zircons, obtained from drilling into very deep granites, contain uranium
which has partly decayed into lead. By measuring the amount of uranium
and 'radiogenic lead' in these crystals, one can calculate that, if the
decay rate has been constant, about 1.5 billion years must have passed.
(This is consistent with the geologic 'age' assigned to the granites in
which these zircons are found.) There is a significant amount of helium
from that '1.5 billion years of decay' still inside the zircons. This is
at first glance surprising, because of the ease with which one would
expect helium (with its tiny, light, unreactive atoms) to escape from
the spaces within the crystal structure. There should hardly be any
left, because with such a slow buildup, it should be seeping out
continually and not accumulating. Drawing any conclusions from the above
depends, of course, on actually measuring the rate at which helium leaks
out of zircons. This is what one of the recent RATE [2] papers reports
on. The samples were sent… to a world-class expert to measure these
rates. The consistent answer: the helium does indeed seep out quickly
over a wide range of temperatures. In fact, the results show that
because of all the helium still in the zircons, these crystals (and
since this is Precambrian basement granite, by implication the whole
earth) could not be older than between 4,000 and 14,000 years. In other
words, in only a few thousand years, 1.5 billion years' worth (at
today's rates) of radioactive decay has taken place. Interestingly, the
data has since been refined and updated to give a date of 5680 (+/-
2000) years." [3]
Footnotes:
1. D. Russel Humphreys, Steven A. Austin, John R. Baumgardner, Andrew A.
Snelling, Helium Diffusion Rates Support Accelerated Nuclear Decay;
Article available online at
http://www.icr.org/research/icc03/pdf/Helium_ICC_7-22-03.pdf.
2. The "RATE" project stands for, "Radioisotopes and the Age of The
Earth"
3. Carl Wieland, RATE Group Reveal Exciting Breakthroughs, 2003


Replies to this message:
 Message 2 by crashfrog, posted 02-24-2004 2:41 AM abee has responded
 Message 4 by kongstad, posted 02-24-2004 4:49 AM abee has responded
 Message 7 by JonF, posted 02-24-2004 9:04 AM abee has not yet responded
 Message 11 by Brad McFall, posted 02-24-2004 3:17 PM abee has not yet responded

  
crashfrog
Member (Idle past 329 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 2 of 11 (88301)
02-24-2004 2:41 AM
Reply to: Message 1 by abee
02-24-2004 2:31 AM


1. The rate of decay remains constant.

This isn't an assumption. We have evidence that decay rates have been constant for at least the last 2 billion years. There's no evidence that rates vary under ordinary circumstances, or circumstances that would leave no other evidence.

2. There has been no contamination (that is, no daughter or
intermediate elements have been introduced or leeched from the specimen
of rock).

Not an assumption. Contamination would leave evidence that we could detect.

3. We can determine how much daughter there was to begin with (if
we assume there was no daughter to begin with, yet there was daughter at
the formation of the rock, the rock would have a superficial appearance
of age).

Not true. Not all radiometric dating requires zero original amounts of daughter isotope, apparently.

That's about all I know. I'm no scientist but that's what I've picked up from the board. As for the helium stuff I'm pretty sure that's been refuted before...


This message is a reply to:
 Message 1 by abee, posted 02-24-2004 2:31 AM abee has responded

Replies to this message:
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abee
Inactive Junior Member


Message 3 of 11 (88310)
02-24-2004 3:17 AM
Reply to: Message 2 by crashfrog
02-24-2004 2:41 AM


Yes, it was the helium stuff I was wondering about too. I'm sure I've read something about it but not scientist enough to know where and be able to quote. Most of this YEC stuff on christian websites is designed to sound important and scientific (to non-scientists) but in fact relies on ignorance to be believed. So if i'm going to argue with them I cant afford to be ignorant either.

However I'm sure resident scientists must be getting irritated with having to refute the same silly theories again and again and again.


This message is a reply to:
 Message 2 by crashfrog, posted 02-24-2004 2:41 AM crashfrog has not yet responded

Replies to this message:
 Message 9 by JonF, posted 02-24-2004 9:20 AM abee has not yet responded
 Message 10 by Sylas, posted 02-24-2004 3:07 PM abee has not yet responded

  
kongstad
Member (Idle past 1732 days)
Posts: 175
From: Copenhagen, Denmark
Joined: 02-24-2004


Message 4 of 11 (88316)
02-24-2004 4:49 AM
Reply to: Message 1 by abee
02-24-2004 2:31 AM


Hi

I can recommend at least two FAQs on www.talkorigins.org

http://www.talkorigins.org/faqs/dating.html

Is about dating, and

http://www.talkorigins.org/faqs/isochron-dating.html

is about isochron dating methods. Now these methods assume that the rate of decay has remained constant. Contamination can be identified with almost certainty, and the initial amount of isotopes need not be known (in fact the methods calculate the initial amounts!)

I like the second FAQ, very much, and have never seen any YEC even trying to argue against these methods.

If you need more info, the pick up a copy of Dalrymples excellent book

Dalrymple, G. Brent, 1991. The Age of the Earth. California: Stanford University Press, ISBN 0-8047-1569-6

Cheers
/Søren


This message is a reply to:
 Message 1 by abee, posted 02-24-2004 2:31 AM abee has responded

Replies to this message:
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abee
Inactive Junior Member


Message 5 of 11 (88319)
02-24-2004 5:16 AM
Reply to: Message 4 by kongstad
02-24-2004 4:49 AM


armed and dangerous
Thanks!

This message is a reply to:
 Message 4 by kongstad, posted 02-24-2004 4:49 AM kongstad has not yet responded

Replies to this message:
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wj
Inactive Member


Message 6 of 11 (88320)
02-24-2004 5:52 AM
Reply to: Message 5 by abee
02-24-2004 5:16 AM


Re: armed and dangerous
And Roger Weins' article is very informative and readable. And, as a bonus, he addresses some specific creationist arguments. Enjoy.

This message is a reply to:
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JonF
Member
Posts: 6173
Joined: 06-23-2003


Message 7 of 11 (88341)
02-24-2004 9:04 AM
Reply to: Message 1 by abee
02-24-2004 2:31 AM


1. The rate of decay remains constant.
2. There has been no contamination (that is, no daughter or
intermediate elements have been introduced or leeched from the specimen of rock).
3. We can determine how much daughter there was to begin with (if we assume there was no daughter to begin with, yet there was daughter at the formation of the rock, the rock would have a superficial appearance of age).
Are these foundational assumptions reasonable? Recent findings seem to indicate that though we ourselves have not been able to vary the decay rates by much in the laboratory, the decay rates may have been accelerated in the unobservable past [1].

You've received some good replies already. I'd like to add something.

Assumption one is an assumption as far as geochronologists are concerned, but it is definitely not an assumption as far as physicists are concerned; they've tested it six ways from Sunday. Sylas recently posted an excellent message on this subject with further details, at Re: summing up, & one more question. One or two recent results that call this into question don't mean much when stacked up against the literally thousands of results that support it. In theory we could find that there has been significant change in radioactive decay rates, in the sense that any finding in science could possible be overturned; in practice, don't bet on it. It ain't gonna happen. Decay rates are constant.

Assumption two is used only for certain types of radioisotope dating, and is not a basis for the mostly widely used methods. The most popular types of dating used today, isochron dating and concordia-discordia dating, indicate when assumption three is violated; in that situation isochron dating tells us that it can't give us a date, but concordia-discordia dating can often give us a good date even when assumption three is violated. It is faintly possible that once in a great while it happens that a rock gives a false appearance of age when measured by these methods, by random chance assemblage of just the right concentrations of chemicals, but it is not possible that all or even a large number of age determinations are wrong; that would be like winning the grand prize in the lottery every time you bought a ticket. (The age errors that the YEC's keep coming up with are just about all obtained by improper sample selection and/or inappropriate measurement method selection).

Assumption three is, again, true only for certain types of radioisotope dating. Both isochron methods and concordia-discordia methods, do not rely on this assumption. In isochron methods, the amount of initial daughter is measured as part of the procedure. Again it is faintly possible that once in a great while it happens that a rock gives a false appearance of age when measured by isochron methods, but again it is not possible that all age determinations are wrong.

There's a good, moderaetly technical, explanation of isochron methodology at Isochron Dating and some of the prevviously posted references give brief descriptions. I don't know of any good references on cincordia-discordia dating on the Web. "The Age of the Earth", G. Brent Dalrymple, Stanford University Press, 1991 has a pretty good short section on it.

Note that the YEC's love to discuss potassium-argon (K-Ar) dating, because it's simple, it is used, and it does rely on all three of those assumptions. (The helium stuff mentioned in the OP doesn't have much of anything to do with K-Ar dating). We know that most K-Ar dates are good because they agree so well with other, more robust methods (including methods not based on radioactive decay). K-Ar dating is still used today becasue it's low-cost and pretty reliable, but the majority of dating sutdies are done with other methods, and most K-Ar dates are not published without confirmation by another method or other evidence.

Some more info and links at Radioisotope dating links and information and A Radiometric Dating Resource List.


This message is a reply to:
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JonF
Member
Posts: 6173
Joined: 06-23-2003


Message 8 of 11 (88343)
02-24-2004 9:12 AM
Reply to: Message 4 by kongstad
02-24-2004 4:49 AM


I like the second FAQ, very much, and have never seen any YEC even trying to argue against these methods.

Woodmorappe/Peczkis addressed isochron and concordia-discordia methodology in "The Mythology of Modern Dating Methods", published by the ICR. It's his usual compendium of lies, half-truths, and mined quotes. There are some responses to this posted by Dr. Henke at No Answers in Genesis!.


This message is a reply to:
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JonF
Member
Posts: 6173
Joined: 06-23-2003


Message 9 of 11 (88345)
02-24-2004 9:20 AM
Reply to: Message 3 by abee
02-24-2004 3:17 AM


Yes, it was the helium stuff I was wondering about too. I'm sure I've read something about it but not scientist enough to know where and be able to quote.

See More Second-Rate Science from the RATE Group (part of EVOLUTION/CREATION DIALOGUES) and Helium diffusion in zircons and the replies, and Re: AiG thinks it has a dating "bombshell".


This message is a reply to:
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Sylas
Member (Idle past 4123 days)
Posts: 766
From: Newcastle, Australia
Joined: 11-17-2002


Message 10 of 11 (88405)
02-24-2004 3:07 PM
Reply to: Message 3 by abee
02-24-2004 3:17 AM


abee writes:

However I'm sure resident scientists must be getting irritated with having to refute the same silly theories again and again and again.

Everyone needs a hobby...

This matter was discussed here last year, with some input from resident scientists. The web links given by others are probably better, however.

See: Message 1 and Message 1; and the following meassages in those threads.

Cheers -- Sylas


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Brad McFall
Member (Idle past 3895 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 11 of 11 (88408)
02-24-2004 3:17 PM
Reply to: Message 1 by abee
02-24-2004 2:31 AM


What is needed is a new experimental and theoretical division of each discipline of science as physics has historically survived. But humanists let out the air with/in brining sociology and anthropology up to the level of sophistication in this geological work instead.

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