Freethought & Rationalism Archive

WinAce · 06-22-2002, 01:57 PM

I need some help debunking various claims made by a particularly annoying YEC over on a gaming forum I frequent. I think I can handle most of the standard crap which is explained by TalkOrigins or any of a number of links posted here at one time or another that I've gathered, but as we all know, they just keep bringing up new, undebunked crap. This argument is one I've never seen used before:

Quote:

<a href="http://www.answersingenesis.org/docs2001/0321acc_beta_decay.asp" target="_blank">http://www.answersingenesis.org/docs2001/0321acc_beta_decay.asp</a>

It turns out that bb decay is not the only mechanism by which some ostensibly long-age ‘clocks’ can experience major accelerations in radioactive decay rate. Consider the lutetium-hafnium (176Lu-176Hf) system, which is relatively new, and which is infrequently used by uniformitarian geologists to supposedly date rocks.9 At very high temperatures, part of the 176Lu decay to 176Hf bypasses the conventional slow route, and goes into an isomeric state which has a half-life of only 3.68 hours.10 In other words, part of the 176Lu decay experiences an alternative decay mode to 176Hf which represents, in effect, a shortcut that is 14 orders of magnitude faster than the conventional 176Lu decay (t� = 41 Ga). Moreover, in this particular instance, no changes in the nuclear force are necessary. Extreme temperatures suffice, and the greater they are, the shorter the effective half life of 176Lu decay to 176Hf. In terms of specifics, at temperatures below about 200 million K, t� remains unperturbed at about 41 Ga. But, over the interval of 200 to 300 MK, the effective t� drops precipitously (by nearly 10 orders of magnitude), then begins to level off asymptotically at still higher temperatures. Thus, at 600 MK, the effective t� of 176Lu is only about 8 days!11 This is short enough that if, as discussed earlier, all of the atoms in the universe had been created in a very hot state—which just means very high kinetic energies—(and maintained that way for several hours on the First Day), all the excess 176Hf in existence would have been generated within that short period.

...

This exciting demonstration that isotopic ‘clocks’ can be accelerated at least a billion-fold is good news to creationist scholars. It raises fundamental questions about the temporal stability of isotopic ‘clocks’. What else have we failed to consider in terms of the physics of radioactive decay? The myth of the virtual invincibility of radioactive decay to external forces has been decisively shattered, and the door to further research has now been swung wide open.

I was under the impression that radioactive decay rates remain fundamentally unchangeable. Is this research they mention correct, what are the exact implications to nuclear physics (do modified decay rates under weird conditions work with Uranium or Plutonium, for instance?), and just how the f... did they justify twisting it to support a young earth?

Thanks for the help, and if it's alright with you all I'd like to post other arguments I'm not able to refute myself in this topic in the future.

[ June 22, 2002: Message edited by: Allan ]</p>

RufusAtticus · 06-22-2002, 02:24 PM

Quote:

From the creationist quote:
Consider the lutetium-hafnium (176Lu-176Hf) system, which is relatively new

Note the "relatively new." This give problems because scientists haven't worked the kinks out. Radiometric dating is simply a tool, like computers or a scale. New tools have bugs. AiG has only pointed out that lutium-hafnium has problems. That doesn't disprove the other well established methods. AiG "forgot" to mention that there are some 40 methods that give consitant dates. Ask your opponent to explain the data presented in the following paper.

<a href="http://www.asa3.org/ASA/resources/Wiens.html#The%20Bible%20and%20Science" target="_blank">Radiometric Dating: a Christian Perspective</a>

~~RvFvS~~

ps418 · 06-22-2002, 02:30 PM

Check this out Allan. I think you'll find it quite interesting. This is a direct response to the AiG article by Woodmorappe.

<a href="http://www.talkorigins.org/origins/postmonth/mar01.html" target="_blank">Modifications of Nuclear Beta Decay Rates</a>

Patrick

Tim Thompson · 06-22-2002, 02:40 PM

Radiometric dating works by measuring the time since the "clock" was last "reset". In order for this 176-Lu decay "acceleration" to have any affect on radiometric dating, then the rock must have experienced a temperature of at least 200,000,000 Kelvins, while still remaining in all other aspect an ordinary rock (for reference, the core temperature of the sun is roughly 15,000,000 Kelvins, and the core temperature of a red giant star that has initiated helium fusion is about 100,000,000 Kelvins). The hottest known environment on/in Earth is about 5000 Kelvins around the surface of the solid inner core.

So just ask the creationist person how that rock managed to find itself in a 200,000,000 Kelvin environment (and remain a "rock")? His answer will be that it does not matter, because it proves that decay rates can change. And your answer will be that we already know that <a href="http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/decay_rates.html" target="_blank">decay rates can change</a>, and that the argument is irrelevant. They need to show not how decay rates can change, but how decay rates did change. If they can't do that, they don't have an argument.

<a href="http://www.tim-thompson.com/radiometric.html" target="_blank">Radiometric dating Resource List</a>

ps418 · 06-22-2002, 02:51 PM

Quote:

Originally posted by Tim Thompson:
<strong>Radiometric dating works by measuring the time since the "clock" was last "reset". In order for this 176-Lu decay "acceleration" to have any affect on radiometric dating, then the rock must have experienced a temperature of at least 200,000,000 Kelvins, while still remaining in all other aspect an ordinary rock (for reference, the core temperature of the sun is roughly 15,000,000 Kelvins, and the core temperature of a red giant star that has initiated helium fusion is about 100,000,000 Kelvins). The hottest known environment on/in Earth is about 5000 Kelvins around the surface of the solid inner core.

</strong>

And that's why the AiG article makes only vague references to "very high temperatures," without clarifying whether they mean "hot like Starbucks coffee" or "hot like the core of an exploding star"!

beausoleil · 06-22-2002, 02:57 PM

As a geochronologist, I can confirm that the original article is utter rubbish.

One dates the time at which the rock in question stopped allowing atoms to be rearranged because it had cooled enough for minerals to form. Processes occurring in plasma or before the rock formed have no effect whatsoever, since one looks for isotopic enrichments in the daughter that correlate with the presence of the parent. For instance, feldspars and micas have a lot of potassium and so old rocks have a lot of 40Ar in these minerals. Pyroxene doesn't have much potassium so has less 40Ar. It's the 40Ar/K ratio that corresponds to an age.

Turning to the lutetium hafnium 'problem', all you need to understand is that nuclei can exist in excited states just as atoms (electron configurations) can. Some excited states beta-decay faster than the ground state of the same atom. The effects are seen as elements are formed by nucleosynthesis in stars. I'm not aware of any long-half life radionuclide that has a significant likelihood of existing in an excited state at the temperatures at which a rock could exist, so the article's point is ridiculous.

Undercurrent · 06-22-2002, 06:37 PM

...and magically, the nuclear decay rates of all isotopes that are used in radiometric dating all magically changed in exact synchronization to make 6000-year-old rock look like a 4.5 billion-year-old rock.

Creationists seem to be under this horrible impression that all of the science that contradicts their belief system is based on one-or-two observations, and if they cast doubt on those few observations, the entire ediface would come tumbling down.

That's at least as silly as implying all the rock in the world was heated to supernova temperature to fuck up radiometric dating.

m.

WinAce · 06-22-2002, 07:39 PM

Thanks for the great replies, people. I think they totally demolished the guy's position in the eyes of the forumers because he asked for the topic (which wasn't about evolution, but the existence of God) to be closed because it 'strayed from its originals purpose'.

Naturally, I'm not gonna let him get off that easily.

When he comes back to the original EvC thread, I'm gonna use some of the great data posted by scigirl and others to further make him look ... like an inbred ark dweller

Dr.GH · 06-22-2002, 08:25 PM

It will cost a little, but Dickin, Alan P.
1997 Radiogenic Isotope Geology Cambridge: Cambridge University Press addresses just about any radiometric dating question you come across.

The Lu-Hf system is taken up in his Chapter 9.

It is always a good idea to provide the reference to the creationist nonsense, which you have done. If you will note, the temperatures that must be obtained in order to have any effect on the stability of the Lu-Hf system are those within a star during a supernova event! This would leave a clear record on Earth if these energy levels were ever obtained locally, let alone here on Earth.

The energies involved in the "Creation week scenario" would be so massive that I should think that they would have observable effects on other star systems even today if the universe were only 6K years old. Tim would be the expert there. In fact Tim, could this be an inadvertant opportunity for creation 'science' falsification?

[ June 22, 2002: Message edited by: Dr.GH ]

[ June 22, 2002: Message edited by: Dr.GH ]</p>

beausoleil · 06-23-2002, 03:06 AM

Just to be pedantic, the temperatures required to affect the Lu-Hf system - 300 million Kelvin - are those of the Helium burning shell of an asymptotic giant branch star. This is the temperature of the s-process, which has nothing to do with supernovae.

<a href="http://nedwww.ipac.caltech.edu/level5/Sept01/Meyer/Meyer4_3.html" target="_blank">http://nedwww.ipac.caltech.edu/level5/Sept01/Meyer/Meyer4_3.html</a>

06-22-2002, 02:40 PM	#4
Tim Thompson Regular Member Join Date: Sep 2000 Location: Pasadena, CA, USA Posts: 455	Radiometric dating works by measuring the time since the "clock" was last "reset". In order for this 176-Lu decay "acceleration" to have any affect on radiometric dating, then the rock must have experienced a temperature of at least 200,000,000 Kelvins, while still remaining in all other aspect an ordinary rock (for reference, the core temperature of the sun is roughly 15,000,000 Kelvins, and the core temperature of a red giant star that has initiated helium fusion is about 100,000,000 Kelvins). The hottest known environment on/in Earth is about 5000 Kelvins around the surface of the solid inner core. So just ask the creationist person how that rock managed to find itself in a 200,000,000 Kelvin environment (and remain a "rock")? His answer will be that it does not matter, because it proves that decay rates can change. And your answer will be that we already know that <a href="http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/decay_rates.html" target="_blank">decay rates can change</a>, and that the argument is irrelevant. They need to show not how decay rates can change, but how decay rates did change. If they can't do that, they don't have an argument. <a href="http://www.tim-thompson.com/radiometric.html" target="_blank">Radiometric dating Resource List</a>

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06-22-2002, 02:30 PM	#3
ps418 Veteran Member Join Date: Mar 2001 Location: Louisville, KY, USA Posts: 1,840	Check this out Allan. I think you'll find it quite interesting. This is a direct response to the AiG article by Woodmorappe. <a href="http://www.talkorigins.org/origins/postmonth/mar01.html" target="_blank">Modifications of Nuclear Beta Decay Rates</a> Patrick

06-22-2002, 02:57 PM	#6
beausoleil Senior Member Join Date: May 2002 Location: US and UK Posts: 846	As a geochronologist, I can confirm that the original article is utter rubbish. One dates the time at which the rock in question stopped allowing atoms to be rearranged because it had cooled enough for minerals to form. Processes occurring in plasma or before the rock formed have no effect whatsoever, since one looks for isotopic enrichments in the daughter that correlate with the presence of the parent. For instance, feldspars and micas have a lot of potassium and so old rocks have a lot of 40Ar in these minerals. Pyroxene doesn't have much potassium so has less 40Ar. It's the 40Ar/K ratio that corresponds to an age. Turning to the lutetium hafnium 'problem', all you need to understand is that nuclei can exist in excited states just as atoms (electron configurations) can. Some excited states beta-decay faster than the ground state of the same atom. The effects are seen as elements are formed by nucleosynthesis in stars. I'm not aware of any long-half life radionuclide that has a significant likelihood of existing in an excited state at the temperatures at which a rock could exist, so the article's point is ridiculous.

06-22-2002, 06:37 PM	#7
Undercurrent Veteran Member Join Date: Jan 2001 Location: Santa Fe, NM Posts: 2,362	...and magically, the nuclear decay rates of all isotopes that are used in radiometric dating all magically changed in exact synchronization to make 6000-year-old rock look like a 4.5 billion-year-old rock. Creationists seem to be under this horrible impression that all of the science that contradicts their belief system is based on one-or-two observations, and if they cast doubt on those few observations, the entire ediface would come tumbling down. That's at least as silly as implying all the rock in the world was heated to supernova temperature to fuck up radiometric dating. m.

06-22-2002, 07:39 PM	#8
WinAce Beloved Deceased Join Date: Feb 2002 Location: Carrboro, NC Posts: 1,539	Thanks for the great replies, people. I think they totally demolished the guy's position in the eyes of the forumers because he asked for the topic (which wasn't about evolution, but the existence of God) to be closed because it 'strayed from its originals purpose'. Naturally, I'm not gonna let him get off that easily. When he comes back to the original EvC thread, I'm gonna use some of the great data posted by scigirl and others to further make him look ... like an inbred ark dweller

06-22-2002, 08:25 PM	#9
Dr.GH Veteran Member Join Date: Jul 2001 Location: Dana Point, Ca, USA Posts: 2,115	It will cost a little, but Dickin, Alan P. 1997 Radiogenic Isotope Geology Cambridge: Cambridge University Press addresses just about any radiometric dating question you come across. The Lu-Hf system is taken up in his Chapter 9. It is always a good idea to provide the reference to the creationist nonsense, which you have done. If you will note, the temperatures that must be obtained in order to have any effect on the stability of the Lu-Hf system are those within a star during a supernova event! This would leave a clear record on Earth if these energy levels were ever obtained locally, let alone here on Earth. The energies involved in the "Creation week scenario" would be so massive that I should think that they would have observable effects on other star systems even today if the universe were only 6K years old. Tim would be the expert there. In fact Tim, could this be an inadvertant opportunity for creation 'science' falsification? [ June 22, 2002: Message edited by: Dr.GH ] [ June 22, 2002: Message edited by: Dr.GH ]</p>

06-23-2002, 03:06 AM	#10
beausoleil Senior Member Join Date: May 2002 Location: US and UK Posts: 846	Just to be pedantic, the temperatures required to affect the Lu-Hf system - 300 million Kelvin - are those of the Helium burning shell of an asymptotic giant branch star. This is the temperature of the s-process, which has nothing to do with supernovae. <a href="http://nedwww.ipac.caltech.edu/level5/Sept01/Meyer/Meyer4_3.html" target="_blank">http://nedwww.ipac.caltech.edu/level5/Sept01/Meyer/Meyer4_3.html</a>

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