Radioactive Half-life measurement

Originally posted by dj2becker
The isotope concentrations can be measured very accurately, but isotope concentrations are not dates. To derive ages from such measurements, unprovable assumptions have to be made such as:

1. The starting conditions are known (for example, that there was no daughter isotope present at the start, or that we know how much was there).

2. Decay rat ...[text shortened]... 3. Systems were closed or isolated so that no parent or daughter isotopes were lost or added.

Looks like someone's got a case of not reading threads.

Originally posted by scottishinnz
Lol, love the "look, proof" bit!


I can't see anything that would alter the decay constant. The only way you might be able to do it would be to expose your radioactive elements to a neutron stream, but that'd cause your radioactive material to go into a run away reaction, and explode. I can see how one method could be fooled - it's easy, jus ...[text shortened]... ars to date a 25 year old rock, but when you have 7 or 8 methods yielding the same date....

When a "date" differs from that expected, researchers readily invent excuses for rejecting the result. The common application of such posterior reasoning shows that radiometric dating has serious problems. Woodmorappe cites hundreds of examples of excuses used to explain "bad" dates.

[J. Woodmorappe, The Mythology of Modern Dating Methods (San Diego, CA: Institute for Creation Research, 1999).]

For example, researchers applied posterior reasoning to the dating of Australopithecus ramidus fossils.

[G. WoldeGabriel et al., "Ecological and Temporal Placement of Early Pliocene Hominids at Aramis, Ethiopia," Nature, 1994, 371:330-333.]

Most samples of basalt closest to the fossil-bearing strata give dates of about 23 Ma (Mega annum, million years) by the argon-argon method. The authors decided that was "too old," according to their beliefs about the place of the fossils in the evolutionary grand scheme of things. So they looked at some basalt further removed from the fossils and selected 17 of 26 samples to get an acceptable maximum age of 4.4 Ma. The other nine samples again gave much older dates but the authors decided they must be contaminated and discarded them. That is how radiometric dating works. It is very much driven by the existing long-age world view that pervades academia today.

Originally posted by dj2becker
The isotope concentrations can be measured very accurately, but isotope concentrations are not dates. To derive ages from such measurements, unprovable assumptions have to be made such as:

1. The starting conditions are known (for example, that there was no daughter isotope present at the start, or that we know how much was there).

2. Decay rat ...[text shortened]... 3. Systems were closed or isolated so that no parent or daughter isotopes were lost or added.

1. Daughter isotope. Estimated by taking a non-radioactive bit of the same strata in the same rock, which is necessarily the same age. I've explained this to you before dj, you just don't listen.

2. Decay constants have always been constant. See my explanation above. dj, you just don't listen.

3. Closed system. Theoretically correct, but practically, losses are less than 1%. Not really an issue. Would actually underestimate age is daughter isotope was lost (which, of course, would become an increasingly larger problem as time goes on and more and more daughter isotope is produced by the decay.

Even with all of your "issues" deej, you still cannot fundamentally alter the ages predicted. Maybe by 5%, but not the 6 orders of magnitude that you require.

Originally posted by dj2becker
When a "date" differs from that expected, researchers readily invent excuses for rejecting the result. The common application of such posterior reasoning shows that radiometric dating has serious problems. Woodmorappe cites hundreds of examples of excuses used to explain "bad" dates.

[J. Woodmorappe, The Mythology of Modern Dating Methods (San Diego, CA ...[text shortened]... It is very much driven by the existing long-age world view that pervades academia today.

Tell you what deej, I'll actually read the original article, then let you know what it says, alright?

Originally posted by scottishinnz
1. Daughter isotope. Estimated by taking a non-radioactive bit of the same strata in the same rock, which is necessarily the same age. I've explained this to you before dj, you just don't listen.

2. Decay constants have always been constant. See my explanation above. dj, you just don't listen.

3. Closed system. Theoretically correct ...[text shortened]... alter the ages predicted. Maybe by 5%, but not the 6 orders of magnitude that you require.

What do you have to say about the occurrence of apparently parentless isotopes with very short half-lives and the possibilities of neutron flux and of the migration of chemically mobile atoms?

Originally posted by dj2becker
What do you have to say about the occurrence of apparently parentless isotopes with very short half-lives and the possibilities of neutron flux and of the migration of chemically mobile atoms?

I say "source?"

Originally posted by dj2becker
... 23 Ma (Mega annum, million years) by the argon-argon method. The authors decided that was "too old," according to their beliefs about the place of the fossils in the evolutionary grand scheme of things. So they looked at some basalt further removed from the fossils and selected 17 of 26 samples to get an acceptable maximum age of 4.4 Ma.

Must still hack you off that they STILL didn't find a 6,000 year figure, with a dinosaur foot print next to it though, huh?

What a conspiracy theorist you are deej.

Originally posted by dj2becker
What do you have to say about the occurrence of apparently parentless isotopes with very short half-lives and the possibilities of neutron flux and of the migration of chemically mobile atoms?

I'd say,

"you wouldn't expect to find the parent isotope of a short lived isotope in a very old rock". I believe that was MY point.

I'd say,

"Neutron flux? Where are these extra neutrons coming from in this radioactive rock? From the other decaying isotopes perhaps? Then they'll follow first order kinetics, and will, of course, already be explained in the decay constant. Where else could they come from deej, and where is your evidence that this ACTUALLY HAPPENED?"

I'd say

"Yes, migration of chemically mobile atoms could be a problem. But it'd have to be an absolutely equal problem in all methods to get the good agreement of dates that we typically get for these methods (the God squad would like to say we got poor agreement between methods, but provided that they are properly applied, it's just not true). See, for example the Zhang paper I cited the other day."

Originally posted by dj2becker
When a "date" differs from that expected, researchers readily invent excuses for rejecting the result. The common application of such posterior reasoning shows that radiometric dating has serious problems. Woodmorappe cites hundreds of examples of excuses used to explain "bad" dates.

[J. Woodmorappe, The Mythology of Modern Dating Methods (San Diego, CA ...[text shortened]... It is very much driven by the existing long-age world view that pervades academia today.

I'll quote directly, ok?

"We have attempted to date several of the tuff units interbedded with the hominid-bearing sediments (Fig. 1) by the single crystal laser fusion 40Ar/39Ar method. Most of the feldspar grains separated for these analyses are contaminated by a dominant population of sanidine grains yielding an early Miocene age (~23.5 Myr). Volcanic rocks represented in the escarpment and plateau to the west are likely sources of these contaminant feldspars. One sample of the GATC (MA92-37), although showing this early Miocene contamination, yielded a dominant feldspar population providing a mean age of 4.387 =+/- 0.031 (s.e.) Myr on the basis of 17 individual crystals (Table 2). This age is viewed as the best estimate for the age of the GATC, and thus provides a maximum age for the hominid remains. The remaining nine grains from this sample represent contaminants, primarily of a Miocene population dated to 23.6 +/- 0.01 Myr. "

"The dated Gaala (GATC; 4.387 +/- 0.031 Myr) and undated Daam Aatu volcanic strata sandwich all but one of the hominid specimens."

So, basically, the rocks are comprised of two things, older sand grains identified to be from a nearby escarpment, and the younger parent clay derived material dated at 4.4 Myrs old. Does sand not blow around in the wind in your universe deej? Have you never felt gritty clay, from sand which blows into it? Are you terminally stupid? Do you never bother to actually read anything?

Originally posted by twhitehead
This site has a lot of good information on dating of rocks. However the basic science that half-lifes can be measured without watching a sample for millions of years is not explained. Also the explanation of how we know that half-lifes do not vary over time is not explained.
The arguement that dj2becker is trying to make is that half-lives are unknown an ...[text shortened]... entally change atoms to such a degree that it would be obvious (eg different chemical reactions)

I've found this thread at another board very useful. It's gotten kind of long since the creationist has basically backed himself into a corner, but the scientists there have done a great job of explaining things clearly. The creationist pulls all sorts of crap out of his kiester (included accelerated decay), and they just patiently explain why he's wrong and how they know what they do.

http://www.iidb.org/vbb/showthread.php?t=156969

Originally posted by telerion
I've found this thread at another board very useful. It's gotten kind of long since the creationist has basically backed himself into a corner, but the scientists there have done a great job of explaining things clearly. The creationist pulls all sorts of crap out of his kiester (included accelerated decay), and they just patiently explain why he's wrong and how they know what they do.

http://www.iidb.org/vbb/showthread.php?t=156969

My grandfather had a friend who buried a dead cow, and like 20 or 30 years later dug it up, got a peice of a bone, and had it tested for its age, It came back with the test results saying it was like 1000 years old, when he told them that it was his cow, they said

"oh, if we wouldve known that, we wouldve done a different type of test, the test we did is for old objects"

LOL, I forget what type of test it was, but I dont trust them so called scientist

Originally posted by flyUnity
My grandfather had a friend who buried a dead cow, and like 20 or 30 years later dug it up, got a peice of a bone, and had it tested for its age, It came back with the test results saying it was like 1000 years old, when he told them that it was his cow, they said

"oh, if we wouldve known that, we wouldve done a different type of test, the test we did i ...[text shortened]... objects"

LOL, I forget what type of test it was, but I dont trust them so called scientist

If your story actually happened there is a very good reason for what they said. Rather than scoff at knowledge you don't understand, read the thread I cited. The creationist makes a similar argument (i.e. scientists have to assume the age of the things that they test in order to get the age of the things they test). The geologists there explain so that even a simple guy like me can understand.

Originally posted by twhitehead
This site has a lot of good information on dating of rocks. However the basic science that half-lifes can be measured without watching a sample for millions of years is not explained. Also the explanation of how we know that half-lifes do not vary over time is not explained.
The arguement that dj2becker is trying to make is that half-lives are unknown an ...[text shortened]... entally change atoms to such a degree that it would be obvious (eg different chemical reactions)

The argument that dj is trying to make is essentially that science data should fit his obsolete religious views.

Originally posted by flyUnity
My grandfather had a friend who buried a dead cow, and like 20 or 30 years later dug it up, got a peice of a bone, and had it tested for its age, It came back with the test results saying it was like 1000 years old, when he told them that it was his cow, they said

"oh, if we wouldve known that, we wouldve done a different type of test, the test we did i ...[text shortened]... objects"

LOL, I forget what type of test it was, but I dont trust them so called scientist

Yes, different tests have different sensitivities. If they used a test that is used to test the ages of things from tens of thousands or millions of years then yes, they'd get a wacky result. Would you use a tape measure to measure the distance to the next star across? Or to measure the size of an atomic nucleus? No? Well, you can't use radiocarbon to date anything older than about 60,000 years, and you can't use it to reliably get data for something as short as 25 years - that's less than 1/2 a percent of the half life of 14C. I am surprised that the scientists who did that test didn't use multiple tests, but they may have only been doing what your uncle specifically told them to do - I don't know.

I would actually be more surprised if this story is actually true - I know that christians aren't above lying to protect their faith. Those tests are pretty expensive, the machines required to do the analysis (which would have had to have been prepped by hand) are horrendously expensive, and the lab techs time even more expensive. Pray tell, why did your uncle decide to spend several hundred dollars to get something radiocarbon dated when he already knew the age?

Originally posted by telerion
(i.e. scientists have to assume the age of the things that they test in order to get the age of the things they test).

Thats the problem with with science in my opionion. They assume the age before they test it, so they know what test to use. Why dont they just assume that the earth is young when they do the test? because they "KNOW" that life evolved from nothing, and in order for that to happen, it wouldve taken millions of years. Get my drift?

I glanced at your thread that you cited, but it looked long, and I got an online college test that needs to be done tonight, I may look into it further later.