Rethinking Radiometric Dating: Evidence for a Young Earth from a Nuclear Physicist by Vernon Cupps was published in 2019 and is part of the Institute for Creation Research’s “In-Depth Science” series of books. The book has 19 short chapters spread over 138 pages. Six of the chapters have only three pages of text, and none of the chapters exceed eight pages of text. One would expect an “In-Depth” book to be, well, in-depth, but none of the chapters are long enough to contain arguments that seriously challenge the validity of radiometric dating.

Young-Earth creationist (YEC) organizations like ICR have tried for decades to show that radiometric dating techniques, such as potassium-argon and radiocarbon dating, are invalid. Rethinking Radiometric Dating is part of that effort. If young-Earth creationists want to make a case that radiometric dating is invalid, however, they need to do much better than what is presented in this book.

Faulty objective

The premise of the book, as stated in the Introduction, is that “Radiometric dating is the pillar upon which the deep-time paradigm stands. If it fails, then deep time fails as a viable explanation for origins” (pp. 9-10). The author should have picked a different goal, because the geological case for an ancient Earth has never depended on the development or legitimacy of radiometric dating techniques.

The antiquity of the Earth was widely accepted among geologists long before the discovery of radioactivity in the 1890s or the development of the first crude radiometric dating methods in the early 1900s. Geologists in the nineteenth century had worked out a relative order of events in Earth history, but could not give absolute ages, such as 541 million years ago for the beginning of the Cambrian Period, and 66 million years ago for the end of the Cretaceous Period. Despite the lack of firm dates, geologists in 1900 and earlier had plenty of reasons to suspect Earth was many millions of years old. Like geologists today, they observed many features in the geologic record that indicate that Earth has a long, complex history that cannot reasonably be compressed down to just a few thousand years. The idea that Earth is many millions of years old is not based on “the secular Humanist Manifestos” (another anachronism in Rethinking Radiometric Dating, pp. 13-14), but on observations of rocks, structures, and landscapes in God’s creation.

The geologic concept of deep time was not dependent on radiometric dating in the nineteenth century, and it is not dependent on radiometric dating in the twenty-first century. Even more than in the 1800s, geologists today are aware of the enormity and complexity of Earth’s rock record. There are many features of Earth’s igneous, sedimentary, and metamorphic rocks; of the fossil record, and of landscapes that speak of the passage of time. It takes time for magma to intrude into Earth’s crust then cool and crystallize, and most batholiths are composed of dozens or even hundreds of individual plutons. The same goes for the eruption and cooling of lava flows, sometimes stacked thousands of feet in thickness with hundreds of individual flows. Other geological processes that take time include dewatering of mud layers, growth of reefs, movement of ions in crystals during metamorphism, creation of animal tracks and nests at numerous levels in sediments, and the formation and melting of continental ice sheets. If radioactivity had never been discovered, these features of Earth’s crust would all point to the passage of time, not to a single catastrophic event.

Biblical Problems

Dr. Cupps is, of course, a committed young-Earth creationist, and the book contains typical YEC rhetoric about the age of the Earth. “Deep time clearly conflicts with the biblical account of creation” (p. 15). “If Scripture is inaccurate in this, then how can it be trusted in anything else?” (p. 54). Cupps does not do much in this book to present the biblical case for a young Earth, so I won’t spend time here making a counter-case. I have written a couple articles outlining my biblical reasons for believing that Genesis does not require a young Earth (here and here), and I refer you to books by theologically conservative Evangelicals for a more in-depth case. I’ll summarize by saying that the Bible does not tell us when “In the beginning” occurred, nor does it tell us that Earth’s fossil record and associated sedimentary, igneous, and metamorphic rocks were formed during Noah’s flood. It certainly does not teach us about nuclear physics, radioactivity, or the geochemistry of radionuclides. YEC geology is not based on a solid exegesis of Genesis, but on debatable extrapolations from Genesis.

I will highlight one rather unusual biblical claim made in the book. On page 52 we read, “Passages such as Psalm 18:7-8, 11-16; Habakkuk 3:8-10, 15; and Deuteronomy 32:22 all seem to suggest that radioactive decay may not have been a part of God’s original creation.” I encourage you to take a minute or two to read these passages. Here’s Deuteronomy 32:32:

“For a fire is kindled by my anger,
    and it burns to the depths of Sheol,
devours the earth and its increase,
    and sets on fire the foundations of the mountains.” (ESV)

Where is the origin of radioactivity in this passage? Is it equated with fire in the depths of the Earth? Is it the source of heat in the roots of mountains? Moses certainly wouldn’t have been thinking such things, and the message of the Song of Moses in Deuteronomy 32 is not a science lesson about geochemistry but one of judgment on Israel for their rebellion. It requires a good amount of eisegesis—reading things into the text rather than drawing meaning out of the text—to see anything about radioactivity in these passages.

Scientific Problems

Acquiring an in-depth understanding of radiometric dating requires a solid foundation not only in nuclear physics or nuclear chemistry, but also in geochemistry, mineralogy, and igneous and metamorphic petrology. Rethinking Radiometric Dating has enough significant scientific flaws that even young-Earth creationists might want to rethink using this book as a resource. Here are a few:

• Claim: “Ultimately, the suggestion that radioisotope dating proves that the earth is approximately 4.7 billion years old and the universe is approximately 13.8 billion years old is not science but rather belief.” (pages 13-14)
  • Response: Astronomers did not use any form of radiometric dating to determine the age of the universe to be 13.8 billion years.
• Claim: “It is particularly interesting that the alpha-decay rates of ²²⁸Th are increased by as much as 10⁴ (10,000 times) under conditions that give rise to high pressure waves. These conditions could have easily existed during the Flood.” (page 51)
  • Response: The claim is that the decay rate of thorium-228 can be accelerated by subjecting it to high pressure in bubbles caused by cavitation in water. The reader isn’t told, however, that the paper referenced in the book has received criticism for its methods and conclusions, and that the results have not been duplicated. This reminds me of the “cold fusion” controversy of the late 1980s, which involved a claim for nuclear fusion in a simple laboratory setup. In the end, cold fusion was not verified, and the researchers and their institutions took a hit in their reputations. In any case, the claim that “these conditions could have easily existed during the Flood” is a hand wave. Thorium is in rocks, not in cavitation bubbles in floodwater.
• Claim: “It has been hypothesized that the heavy elements in our solar system come from a cluster of supernova explosions about 10 million years ago that produced a ‘local bubble’ around our solar system. All heavy elements supposedly came from this explosion.” (page 92)
  • Response: This represents a complete misunderstanding of what geologists and astronomers believe about the origin of heavy elements, and of the paper he referenced. No geologist or astronomer believes that the heavy elements in Earth’s crust, mantle, and core—elements with greater atomic mass than iron—originated from supernova eruptions only 10 million years ago. Does the author believe that old-Earth geologists believe that most of the world’s copper, zinc, rubidium, strontium, platinum, gold, lead, thorium, uranium and about sixty other heavy elements originated only ten million years ago and somehow seeped into all the Archean to Miocene rocks? How did the editors and reviewers at ICR let this one slip through?

I have eight more science-related bullet points in my notes, but these three should suffice to demonstrate that the book contains erroneous scientific arguments.

Am I just being nitpicky?

I have described a few significant scientific problems with the book and believe these are substantial enough to undermine the credibility of the rest of the book. A young-Earth creationist might respond by admitting that the book contains some errors, but that the overall critique of radiometric dating is still valid.

The book lists assumptions behind radiometric dating in the Introduction on page 10 and returns to these assumptions multiple times later in the book.

“All radioisotope dating methodologies have four fundamental assumptions upon which they rely. Those assumptions are:

1. The decay constants are indeed constant throughout time
2. The rock system being dated is a closed system during the age of that system.
3. The initial concentrations of radioisotopes being used for dating a given rock sample are known or can be extrapolated from other known data.
4. Enough decay has occurred to enable the amounts of radiogenically generated daughters to be differentiated and measured.

The problem is not with this list of assumptions (I could give a longer list), and I am not even opposed to YECs questioning the validity of radiometric dating. I don’t find their critiques, however, to be compelling. Here’s my brief response to each:

1. All our observations indicate that relevant decay rates are constant in environments that could credibly be associated with Earth history as outlined in YEC geology. There is no solid evidence that decay rates vary by factors like heat, pressure, magnetism, distance from the sun, or other ordinary means. Decay by electron capture, and to a lesser degree by beta decay, may be affected by complete ionization, but I don’t know of any YECs who propose that Earth’s crust was completely ionized—turned into a plasma—during Noah’s flood. I’m not saying that decay rates have been proven to be invariable, but I don’t think the evidence is out there to back up YEC arguments, including their claims about helium diffusion from zircon. Exotic examples cited by YECs have no relevance for conditions in Earth’s crust or nuclides used in radiometric dating.
2. Geochronologists understand that samples generally need to be a closed system throughout their history to yield reliable radiometric dates. There are several processes that may cause a gain or loss of ions and atoms, such as heating, fluid movement, diffusion, fracturing, and weathering. Points lining up in a straight line for various analyses on an isochron diagram is considered to be evidence, though not absolute proof, that little gain or loss has occurred. There are processes that may produce false isochrons, but it would take a regular occurrence of improbable just-right circumstances to make these false isochrons a regular feature of igneous rocks. Concordance of different methods may also be considered evidence that gain and loss of ions has been minimal.
3. Regarding initial isotopic composition, Dr. Cupps did better than many YECs when he added “or extrapolated from other known data.” In some cases, it is reasonable to believe there were no (or only minimal) daughter nuclides present when the mineral formed. An example is U-Pb dating of zircon. Uranium ions have similar size and charge to zirconium ions, so when zircon (ZrSiO₄) crystallizes from magma, uranium ions in the magma readily substitute for zirconium, and some zircon crystals contain up to 1% uranium. Lead ions, on the other hand, have the wrong ionic charge and radius, and do not easily incorporate into zircon crystals, resulting in fresh zircon having virtually no lead when it crystallizes. It is reasonable to conclude (and possible to verify) that zircon crystals had uranium when they formed, but negligible amounts of lead. If a young-Earth creationist has a problem with this explanation, their problem is with chemistry, not geology.
4. No one disputes that geological samples cannot be dated if not enough decay has yet occurred for daughter nuclides to be distinguished and measured. This is why it is not a good idea to attempt ²³⁸U-²⁰⁶Pb dating (half-life 4.5 billion years) on a sample that is only a few thousand years old.

Geologists know about all these assumptions, and more. Radiometric dating sometimes yields unexpected results, and the reason often has something to do with assumption #2, which is gain or loss of parent or daughter nuclides. Sometimes these “wrong” results tell geologists something about the history of the sample that wouldn’t be known if everything where clean and orderly in the subsurface, so even discordant or unexpected dates don’t mean that radiometric dating is rubbish.

Better Assumptions

I have two basic assumptions regarding geology and radiometric dating:

1. All truth is God’s truth, whether found in God’s world or in God’s word. If there seems to be a conflict between our understanding of God’s world and God’s word, then either we do not understand God’s world correctly, we do not understand God’s word correctly, or perhaps some of each. In the end, if we were to have perfect understanding of both, there will be no conflict.
2. God’s world operates by God’s laws that God built into his creation. Humans, created in the image of God, may study and understand God’s world. Humans, being both limited and sinful, may misunderstand God’s world. This is the Christian foundation for science.

Earlier I made a case that, contrary to the main premise of Rethinking Radiometric Dating, acceptance of an ancient Earth does not depend on radiometric dating. Now I want to make a more important point: The truthfulness of the Bible, and of Christianity, does not depend on proving that radiometric dating is false. The validity of uranium-lead, potassium-argon, rubidium-strontium, and radiocarbon dating—along with dozens of other radiometric dating methods—does not undermine the inspiration, inerrancy, or authority of the Bible. It doesn’t even prove that the literal-days interpretation of Genesis is wrong, though it messes with a lot of YEC speculations about how Genesis translates into geology.

Concluding Thoughts

There is always room on all sides for “rethinking radiometric dating.” Our ignorance always exceeds our knowledge. There are half-lives (decay constants) that are not known as precisely as researchers would like. There are many mysteries to be solved with the application of radionuclide geochemistry to problems of igneous and metamorphic petrology. YECs often bring up radiocarbon in diamonds and dinosaur bones, and I don’t think we have a complete understanding of what is going on. Old-Earthers often explain radiocarbon in diamonds by invoking nuclear reactions involving neutrons from radionuclides, but there don’t seem to be sufficient neutron sources in diamonds to create the amount of carbon-14 YECs report. I suspect that these YEC claims can be answered in entirety by contamination, but further research is needed. Perhaps we would learn something new about God’s creation.

The problems in Rethinking Radiometric Dating demonstrate that it is not primarily old-Earthers who need to do some rethinking about radiometric dating. Perhaps it is time for the YEC community to re-think their overall approach to relating Genesis and geology.

An Additional Thought – I struggled with writing a critical review of a book written by a Christian brother. Nothing in this review should be taken as reflecting negatively on the character, intelligence, or spiritual maturity of the author or those he works with.

Grace and Peace,

Kevin Nelstead

My testimony of how I came to faith in Christ

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