A slightly delayed episode is finally up. Part 2 of the series of 2 on radiometric dating, part 2 of the series of 4 (this month’s theme) on dating techniques. I talk about four of the main categories of claims that young-Earth creationist arguments fall into in their attempts to refute radiometric dating.
It’s also the first regularly formatted episode since #35, including the main segment, new news, Q&A, feedback, puzzler, and announcements.
This is Part 1 of two parts, the next to be in the next episode, conveniently, and will discuss what young-Earth creationists say about the topic.
But in this one, I give you a 50-minute interview with geologist Rachael Acks who explains some of the history of radiometric dating, the very basic physics of it, how it works in practice, and some cases of when and why you can’t use the method.
This month begins a four-part series (though it’ll be labeled as two Parts 1 and 2) on age-dating techniques and then the young-Earth response. The first set is radiometric, second set will be craters. It’s a bit of a different thing, so we’ll see how it works out.
Note that because this interview ran longer than I like to make normal episodes, I’m pushing the not-main segments to Episode 39.
One of the best and most reliable ways to determine the absolute ages of a material is through radiometric dating. Because of this, and because they show the age of things to be older than 6000 years, young-Earth creationists (YECs) have spent decades trying to show that it doesn’t work or just claiming that assumptions that scientists make are not true.
Their attempts at this include bringing samples of newly formed lava to a lab where they find an age of a few million years and then laugh saying that it only formed a decade ago. (Two issues there are that (1) the type of dating employed isn’t accurate for a sample younger than 500,000 years, and (2) they dated small minerals in the lava that did not melt in the original lava so actually were many millions of years old.)
Or they will claim that radiocarbon dating isn’t even used for dating dinosaur fossils … leaving out that radiocarbon dating can’t be applied to things that are more than ~50,000 years old.
Anyway, all that’s for another post. The purpose of this post is to point out that the point of science is to develop a model that can be applied to everything it attempts to describe. Gravity works the same on Earth as on the moon as in the center of a galaxy cluster. For the issue at-hand, YECs need to decide whether they believe in radiometric dating and its usable, or whether they don’t and so don’t use it.
In the news over the past week, yet another group of YECs have claimed to discover Noah’s Ark on top of Mt. Ararat in Turkey. There are many outlets for this story, but out of fun, I’ll link to the one over at FOX News. The relevance to radiometric dating? I’ll quote (emphasis mine):
“The group claims that carbon dating proves the relics are 4,800 years old, meaning they date to around the same time the ark was said to be afloat. Mt. Ararat has long been suspected as the final resting place of the craft by evangelicals and literalists hoping to validate biblical stories.”
Didja see that? Meanwhile, over at Answers in Genesis:
“All radiometric dating methods are based on assumptions about events that happened in the past. If the assumptions are accepted as true (as is typically done in the evolutionary dating processes), results can be biased toward a desired age. In the reported ages given in textbooks and other journals, these evolutionary assumptions have not been questioned, while results inconsistent with long ages have been censored.”
Or from an older Institute for Creation Research article:
“Creationists are not so much interested in debunking radiocarbon as we are in developing a proper understanding of it to answer many of our own questions regarding the past. At the present time it appears that the conventional radiocarbon dating technique is on relatively firm ground for dates which fall within the past 3,000 years. For periods of time prior to this, there are legitimate reasons to question the validity of the conventional results and seek for alternative interpretations.”
Or, a case of very special pleading from another ICR article:
“A ‘Back to Genesis’ way of thinking insists that the Flood of Noah’s day would have removed a great deal of the world’s carbon from the atmosphere and oceans, particularly as limestone (calcium carbonate) was precipitated. Once the Flood processes ceased, C-14 began a slow build-up to equilibrium with C-12—a build-up not yet complete. Thus carbon dating says nothing at all about millions of years, and often lacks accuracy even with historical specimens, denying as it does the truth of the great Flood. In reality, its measured disequilibrium points to just such a world-altering event, not many years ago.”
You can’t have it both ways. Or all four ways (I kinda lost count). Either (1) radiometric dating doesn’t work, (2) radiometric dating does work once you account for things that YECs have yet to really define, (3) it does work for the recent past to 3,000 years ago but not for anything before that, or (4) it works for everything made after the flood (as in the ark was built before the flood so can’t be dated with it).
What this all boils down to is the Inconsistency Fallacy, one I didn’t address in my series the last two months of 2009 on Logical Fallacies (but I do intend to return to that series later this year). The Inconsistency Fallacy is basically summarized as, “Multiple statements that contradict one another.” For example: “Statement A is true and B is true. Use one of these statements to prove the other is false.” Or, “Bill is younger than Jill, and Jill is younger than Charles. Charles is the oldest of the three.”
And that’s the case here. Either it’s valid, or it isn’t. You can’t use radiometric dating to claim the Bible is literally true to claim that radiometric dating doesn’t work.
In the early days of 2010, specifically January 4, I read an article on Wired Science entitled, “Age of Solar System Needs to Be Recalculated.” After having written this blog for nearly a year and a half and having a fair number of posts about young-Earth creationism (YEC), I read the article knowing that it would just be a matter of time before someone at either the Institute for Creation Research (ICR) or Answers in Genesis (AiG) would use the article to effectively say, “Look! See!? Scientists don’t know what they’re doing, all of radiometric dating is wrong, creationism is right!” And they didn’t disappoint, though I have to admit it took longer than I thought it would (17 days).
The process of radiometric dating and all its corollaries and techniques could likely fill a decent-sized graduate textbook. That’s not the purpose here, rather it’s to give you the most basic information so you can understand the issues at-hand.
The principle behind radiometric dating is that every atom has many different isotopes. An atom is made of protons, neutrons, and electrons. The number of protons determines what atom it is (1 proton = hydrogen, 2 protons = helium, etc.). The number of neutrons determines the isotope (1 proton = hydrogen-1, 1 proton + 1 neutron = hydrogen-2 (deuterium), 1 proton + 2 neutron = hydrogen-3 (tritium)). The electron number determines the ionization state, which is unimportant for this discussion.
Atoms that get too heavy are inherently unstable. If you cram too many protons and neutrons into the center, the atom will decay. If you cram too many neutrons into an already stable isotope of an atom, it will decay. “Decay” is when it releases either one or more of its neutrons or protons by turning it into something else. That decay time is based purely on fundamental physical laws and constants, it is a quantum mechanical process, and it is different for all isotopes.
The time over which half of a sample of an isotope will decay into another is called the “half-life.” After two half-lives, 75% will have decayed; after 3, 87.5%, after 4, 93.75%, etc. (1-0.5# of half-lives). Half-lives can be measured over human timescales, and/or they can be correlated with other established dating mechanisms, such as ice-cores, tree rings or written records.
An assumption of radiometric dating and necessary corollary is that the sample is from a self-contained system. In other words, it has to be “original;” if the sample was contaminated some time after it formed, then the dating will be thrown off. Similarly, we need to know how much of the original “parent” isotope was present relative to the “daughter” isotope so that the amount of original daughter isotope can be removed from the equation.
The Wired Science was reporting on an article from Science News, which itself was reporting on an article published in the journal Science at the end of 2009. (Unfortunately, you have to pay for the article unless you are at an institution that has a subscription. The citation is, Brennecka et al. (2010). “238U/235U Variations in Meteorites: Extant 247Cm and Implications for Pb-Pb Dating.” doi: 10.1126/science.1180871. An earlier abstract of their findings can be found for free here.)
It had been assumed for years that the amount of original uranium-238 and uranium-235 in asteroids was even throughout all the asteroids. This had been measured independently many different times and the ratio had been the same. However, there is no theoretical reason why this should be true, and so people kept measuring it to continue to check the results. What these researchers found was that, actually, when measured more accurately and taking a few more things into account, that there actually are slight differences and the ratio isn’t quite what it was thought to be.
What does this do? It changes the age of the solar system by 1 million years. So it could be either 4.566 or 4.567 billion years old.
One of the co-authors explicitly states, “It’s not as if this age-dating process doesn’t work anymore,” says coauthor Ariel Anbar, also of Arizona State. “But if you want to push this isotope system to get ages that are really precise, suddenly we realize that there’s this variation you need to take into account.””
What they did not find is that radioactive decay rates are not the same within a given isotope. As I stated above, that is set by the fine-structure constant of the universe and purely quantum mechanical processes.
The very first sentence of ICR’s January 21, 2010 article, “It’s Official: Radioactive Isotope Dating Is Fallible,” states: “New data collected by secular researchers has confirmed what creation scientists discovered decades ago—geologists’ cornerstone assumption that the rate of radioactive decay is constant over time is not correct.”
Except … NO! That was NOT what the article nor paper nor abstracts nor researchers said.
Moving on … the third paragraph starts with, “Gregory Brennecka of Arizona State University and colleagues measured the relative amounts of Lead 238 to that of the stable Lead 235 from several samples taken from the large Allende meteorite, named for the village in Mexico near where it landed in 1969.”
Again … NO! They used uranium-238 and uranium-235 as a proxy for lead-206 and lead-207.
Next paragraph: “The differing amounts of material that were found in separate samplings of the same meteorite should not have been detected if isotopic decay of Uranium is indeed stable over time.”
NO! The parts of the same meteorite that the researchers analyzed are almost guaranteed to have formed at the same time because – in part – they are in the same meteorite. Therefore, if the rate were to change through time, then they all should still show the same ratio of parent to daughter isotope because they all would be changing at the same rate. Therefore, what it shows and what the researchers concluded is that the original ratios were slightly different.
Brian Thomas, the ICR article’s author, goes on a quote-mining expedition for the next two paragraphs to try to show that radiometric dating was never an established thing.
He then goes on the expected, “But creationists knew it wasn’t!” by stating, “For years, creation researchers have published ample data to refute the assumed stability of nuclear decay rates in general, as well as specifically for Lead.” (Again missing the actual point it was uranium that they were analyzing.) He continues with standard YEC arguments after that.
Thomas closes with: “Although Brennecka and his colleagues detected only a small difference in the same Lead isotope amounts in the same rock, this was quite enough to falsify any notion that this Lead 238 decays at a constant rate into Lead 235. And this dovetails with other valid research which found similarly falsifying data.”
This is a standard creationist tactic: (1) They find anything that is an iterative step in science (in this case refining an established dating mechanism and showing that at the 0.1% level there are additional issues to take into account). (2) Misrepresent it. (3) Find supporting quotes through quote-mining that shows that “even secular scientists” had doubted the technique. And (4) therefore God did it 6000 years ago.
Every quote presented above was copy-pasted from the original ICR article. The next day, I was notified in the comments section below that the article had been revised “for accuracy.” As it now reads, every quote that I took has been either slightly or wholly changed. The most obvious is that they have fixed the “lead 238/235” to make it uranium.
But perhaps more interestingly, the language is less scathing. For example, the opening paragraph is now, if one were to show the edits via strikethroughs and insertions:
“New data collected by secular researchers has confirmed what creation scientists discovered decades ago — geologists’
cornerstoneassumptionsthat the rate ofabout radioactive decayis constant over time isare not always correct.”
Is it just me, or does that actually seem to be a softening of the language? It actually seems to represent the research now.
Then there’s this one:
“The differing amounts of material that were found in separate samplings of the same meteorite
should not have been detected if isotopic decay of Uranium is indeed stable over timewere unexpected.”
Again … the language seems softer and actually seems to represent the research. The rest of the article is still effectively, “This calls all radiometric dating into question,” but at least it’s not based on quite an obvious straw man. Thank you KT_trebor for pointing out the revision!
Exposing PseudoAstronomy 