Carbon Dating

It is difficult to discuss the age of the earth without at some point referencing radiometric dating. I am going to give my best summary of the dating process itself because too often I have heard people dismiss radiometric dating offhand without even understanding the process. After that, I will discuss carbon dating more specifically.

All ordinary substances are made of atoms, and atoms are composed of protons, neutrons, and electrons. The type of element is determined by the number of protons. The number of neutrons in an atom of a certain element determines the isotope of that atom. This does not affect the chemical properties of the atom. However, if the atom has either too many or too few neutrons, then it is unstable, or radioactive. An atom of a radioactive isotope will at some unknown point in time undergo one of several types of radioactive decay, in which certain particles are ejected from the atom, resulting in the atom changing from one element to another.

Although it cannot be known when any particular atom will decay, it can be predicted with great accuracy when any given percentage of a radioactive sample will have decayed. Therefore, if we know how much of a radioactive isotope existed originally in something and how much is in it currently, then we can quite easily calculate its age.

Now the most obvious complication in this process is that the initial concentration of a radioactive isotope in an object typically is not immediately evident. However, there are ways in which it can be determined with confidence. Some of these are more straightforward than others.

One of the more straightforward methods of radiometric dating is carbon dating, which is used to find the age of once-living organisms or of materials made from them. Carbon-12 (6 protons, 6 neutrons) comprises most of the carbon on earth, but a small percentage is radioactive carbon-14 (6 protons, 8 neutrons). Because living things constantly exchange carbon with their environment, every living organism that takes in carbon primarily from an atmospheric source has the same ratio of carbon-14 to carbon-12 as that found in the atmosphere. After the organism dies, however, carbon is no longer exchanged with the environment, and the carbon-14 within it decays at a predictable rate, with half of the remaining carbon-14 decaying every 5730 years.

The historical levels of atmospheric carbon-14 have not been perfectly constant, but they can readily be determined by analyzing tree rings. The wood in the inner rings of a tree is as old as those rings themselves. For example, the innermost ring of a 1000-year-old tree is 1000 years old. By finding the relative amounts of carbon-12 and carbon-14 in this ring, knowing its age, it is a simple matter to determine the ratio of carbon-12 to carbon-14 in the ring (and thus in the atmosphere) when the ring was formed. This provides a reliable calibration for the carbon-dating process, enabling carbon dating to be performed with confidence. This calibration based on tree rings extends around 10,000 years into the past. Other methods exist for calibrating the carbon-14 record further into the past, but with significantly greater uncertainty.

It is certainly possible for carbon dating to be performed inappropriately. For example, marine organisms (or animals that eat primarily marine organisms) cannot be dated by this method because they obtain carbon from an oceanic source, which does not have the same level of carbon-14 as the atmosphere. Carbon dating a seal or a penguin, for instance, will yield a result far older than its actual age.

I have heard it argued that the carbon dating method cannot be reliable (or else that the earth must be young) because significant amounts of carbon-14 have been found in coal that supposedly is millions of years old, by which point virtually all of the carbon-14 should have decayed. This is true, but it is only half of the story. Some coal contains carbon-14, and some does not. The amount of carbon-14 varies greatly from one coal deposit to another, and there is a correlation between the amount of carbon-14 in the coal and the radioactive content of the surrounding rocks. This suggests that the carbon-14 may be produced in the coal by radiation emitted from nearby rocks. This is a subject of ongoing research.

Carbon dating has consistently been shown to be a reliable process. For example, it is used for dating biblical manuscripts and consistently yields dates in agreement with other methods (e.g., handwriting analysis). When used properly, carbon dating is a powerful tool for determining the ages of once-living things.

I should note that although I have had this article drafted for quite a while, it has taken me a long time to publish it. This is partly because my employer has been giving me more work (which is a good thing), partly because I have been occupied with other projects, and partly because I just wasn’t happy with the way it came out and could not improve it to my own satisfaction. However, I do have much more to say, so I will publish this and move on.

Tree Ring Dating

Most everyone knows that trees have rings. Each year, a tree grows a new ring. The age of a tree typically can be determined by counting the rings. I bring this up because counting tree rings proves that the earth must be more than 11,000 years old.

Now it’s a little more complicated than I have implied (but only a little). The oldest known living tree is 5065 years old. This fact alone places into question the young-earth chronology in which a global flood devastated the earth only 4360 years ago.

Creative Commons Attribution-ShareAlike 2.0 Generic License by Albert Bridge

Each ring consists of both light and dark wood and corresponds to one year of growth.

Tree rings carry information. Each ring contains two types of wood. The first type, which forms at the beginning of the growing season, is called the early wood. It is less dense and is lighter in color. The second type, which forms at the end of the growing season, is called the late wood. It is denser and is darker in color. The thickness of the early wood and the late wood formed in a given year is an indication of the nature of the growing season in that year. A long, warm growing season with plenty of rainfall produces a wide ring. A cold growing season or one with little rainfall produces a narrow ring.

Creative Commons Attribution 2.0 Generic License by ilya_ktsn

Bristlecone pines such as this one include the oldest known living trees.

Now a warm year for one tree is also a warm year for other trees in the same area. As a result, one would expect a correspondence between the widths of the rings of different trees in the same area. This is, in fact, the case. Trees of the same type living in the same area at the same time show the same pattern of wide and narrow rings.

Suppose that one were to find a piece of fossilized wood of unknown age. It may be possible to match the rings of that wood to the rings of living trees of the same type in the same area and hence to determine the age of the wood. Now suppose that a reliable match is determined but that the fossilized wood also has rings that were formed before the earliest ring of the living tree. The record of tree rings then encompasses a span of time longer than the age of the oldest living tree.

This process has been carried out by scientists many times, resulting in continuous tree ring records that, in some cases, stretch much farther back through time than the age of the oldest living tree. The longest continuous tree ring record of this sort spans more than 11,000 years.

At this point, I might typically answer some objections or address opposing arguments. However, there really is nothing in that respect to be done because Answers in Genesis has already done it. They have analyzed this issue and have affirmed that the rings are indeed correctly cross-matched and that the bristlecone pines are not capable of producing more than one ring per year.

So not only do we have direct evidence that trees have been growing on the earth for more than 11,000 years, but we also have evidence concerning the nature of those years and even the amount of carbon-14 present in the atmosphere in each year—which will be the subject of the next post.

Orthodoxy and the Timing of Creation

In recent times, in many Christian circles, young-earth creationism has begun to be considered a point of orthodoxy. Now I consider orthodoxy a very good thing, and I lament the lack of standards of orthodoxy in much of Protestantism. However, I do not believe that the manner or timing of creation should be considered a point of orthodoxy.

I think that anybody who calls themselves a Christian should be able to affirm the Nicene Creed, and I also believe that true Christianity should embrace the five solas of the Reformation. The Nicene Creed is a summary of essential Christian beliefs, written by the church fathers and affirmed by Christians for 1600 years. It says nothing about the manner or timing of creation.

The church fathers were not even all calendar-day creationists. Sure, most of them were. But we know that the notable early Christian pastors and theologians Clement of Alexandria, Cyprian, and Augustine did not hold to the calendar-day perspective of Genesis. Apparently, calendar-day creationism was not considered a point of orthodoxy in the second, third, and fourth centuries.

Augustine of Hippo, a notable church leader of the fourth century, believed that God created everything instantly. This view was not considered heretical by the church.

Now it is true that the Westminster Confession of Faith states that God created “in the space of six days.” The Presbyterian Church of America (which holds steadfastly to the Westminster Confession) formed a committee in 1998 for the purpose of researching and interpreting this statement and evaluating positions on creationism. The committee’s report was submitted two years later with the conclusion was that the statement was written with regards to the view of instantaneous creation and not with regards to a day–age interpretation. The committee did not find the day–age interpretation to contradict the Westminster Confession.

Yet any deviation from calendar-day creationism is still viewed by many as a mark of theological liberalism. Personally, I am in agreement with the 1689 London Baptist Confession (except regarding the Pope being the Antichrist, rest being forbidden on the Lord’s Day, or the elements of the Lord’s Supper being made holy by prayer). I challenge you to read this confession and judge for yourself whether there is any way that someone who agrees with it could possibly be considered liberal.

So maybe we should worry less about teaching young-earth creationism in our churches and more about refuting actual heresies, such as Pelagianism, modalism, and prosperity theology, which have begun to overrun the Protestant churches.

Allegory and Evolution

I recently listened to a pastor I respect talk about old-earth creationism. He made a statement to the effect that if you believe that Genesis should be interpreted allegorically, you shouldn’t even call yourself a Christian. It may come as a shock, but I pretty much agree with him on this.

You see, if Adam and Eve were allegorical, then their sin was also allegorical. And if Adam’s fall is allegorical, how can Christ’s redemption be anything but allegorical? This interpretation necessarily denies the reality of original sin and reduces Christianity, at best, to Pelagianism, a view that clearly contradicts the teaching of scripture (John 6:44, Rom. 5:19, Eph. 2:3) and that has been denounced as heresy by multiple church councils. Orthodox Christianity requires a literal Adam and a literal fall.

Now let’s take a look at evolutionary creationism, also known as theistic evolution. According to this model, God directed the process of evolution by which simple organisms eventually developed into humans. (BioLogos is an organization that promotes this view.) According to evolutionary theory, it is populations that evolve, not individuals. As a result, if humans evolved by natural selection, it is not possible that there could have been a single first human or pair of humans (Adam and Eve).

Now it can be argued that Adam and Eve were not the first humans but that, instead, God took these two individuals from among the population of modern humans and breathed into them the breath of spiritual life, instilling into them the image of God. According to this view, the fall remains a literal event. I think that this may be the only position regarding Adam and Eve that an evolutionary creationist can take without falling into total heresy. Although I do not consider this view heretical, I will still argue that it is wrong.

Genesis 2:7 says, “the Lord God formed a man from the dust of the ground.” There are other verses in the Bible that speak of God forming people. In Psalm 139:13, for instance, David says, “You knit me together in my mother’s womb.” However, I think there is a big difference between God forming a person in his mother’s womb and God forming a person from the dust of the ground. It seems to me that Genesis 2:7 indicates a special act of creation not involving birth from a mother. If Adam were taken from an existing human population, then God did not form him from the dust of the ground.

This is why I do not think that the theory of evolution by natural selection (at least concerning the origin of man) is compatible with biblical Christianity. Eventually, I will explain why I do not think biological and paleontological evidence demands an evolutionary interpretation. However, that will have to wait for another time.

The Grand Canyon and the Toutle River

In my last post, I began a discussion of the Grand Canyon. I pointed out that although floods certainly can create layers of rock, a flood could not possibly have created the specific layers in the specific sequence found in the Grand Canyon. Now let’s consider the formation of the canyon itself. Young-earth creationists frequently compare the Grand Canyon to the Toutle River canyon, which was formed by a mudflow during the eruption of Mount St. Helens. They claim that water released after the flood by the breaking of a dam could have formed the Grand Canyon. However, these two canyons really are not at all alike. I can identify four different reasons why the method by which the Toutle River canyon was formed cannot explain the formation of the Grand Canyon.

  1. This canyon was created by a mudflow during the eruption of Mount St. Helens.

    The source of the material that produced the Toutle River canyon is evident. There is no evidence of a reservoir that could have provided the water necessary to quickly produce the Grand Canyon. Because the amount of sediment removed from the canyon has about the same volume as Lake Michigan, the reservoir that formed the canyon must have had a volume at least equal to several times that of all the Great Lakes combined. The prehistoric lakes that are invoked to explain the source of the water simply do not have sufficient volume to remove this much material.

  2. The Toutle River canyon is most pronounced near the foot of the mountain.

    The Toutle River canyon is most pronounced close to its source at Mount St. Helens and diminishes as it moves away from the mountain. This makes sense for a canyon that has as its cause a release of fluid from a particular source. The Grand Canyon, however, begins as a relatively small canyon in central Utah and becomes deeper and wider as it travels through the Colorado Plateau, until reaching its widest and deepest point hundreds of miles downstream in northern Arizona. This is not consistent with a catastrophic formation.

  3. The Grand Canyon has plenty of twists and turns.

    The Toutle River canyon is more or less straight, although it does make a few gentle turns as a result of the topography of the surrounding terrain. The Grand Canyon follows a meandering path, including a number of U turns, across an otherwise flat plateau. Water rushing with enough force to carve out a canyon does not follow a meandering path.

  4. Here, a tributary joins the Colorado River in a canyon of its own.

    The Toutle River canyon is a single channel. The river in the Grand Canyon has numerous tributaries. These tributaries, where they join the Colorado River, are in “tributary canyons” as deep as the primary canyon. Water originating from a single source and rushing with enough force to create a canyon does not form tributary canyons.

So yes, canyons can be formed quickly. But the Grand Canyon could not have been formed quickly. The explanation more consistent with the physical evidence is that it was eroded over the course of many years through solid rock by a river following a meandering path across a relatively flat plateau.

Rocks of the Grand Canyon

I’m not sure whether a debate about the age of the earth has taken place in recent times without any reference being made to the Grand Canyon. Most scientists claim that it must have taken many years to form, but those who believe in a young earth claim that it could have been formed quickly. These people point primarily to two known facts: Large floods can deposit layers of sediment, and canyons can form quickly. Using this information, they conclude that a global flood could have created all (or most) of the rock layers seen in the canyon and that a large flash flood caused by a dam bursting shortly after the flood could have carved out the canyon itself. Does this explanation hold water (pun intended)? What are the facts concerning the Grand Canyon, and are they compatible with formation by a global flood? Today I will address the formation of the rock layers seen in the Grand Canyon, and next time I will address the formation of the canyon itself.

Nobody disputes that floods can and often do deposit layers of sediment. However, a more specific question is warranted: Could the particular types and sequence of rock layers found in the Grand Canyon have been formed by a single flood event? This is a question that I have never heard young-earth creationists address.

The young-earth creationists typically point out that if you shake up a jar of muddy water and let it settle, it will form layers according to the densities of the suspended particles. They claim that this is how rock layers formed in the flood. It is true that floods can form layers in this manner. The coarsest sediments end up on the bottom, and the finest sediments end up on the top. However, this is not what we observe in the layers of rock found in the Grand Canyon area.

You see, the top layer of rock in the Grand Canyon area is limestone (#1 in the diagram). Beneath that is a layer of sandstone (#3). Beneath the sandstone is siltstone (#4), and beneath the siltstone is more limestone (#7). If these layers were all formed at the same time by settling of particles after a global flood, then we should expect the sand to have settled before the silt. It should not be possible in this context for a sandstone layer to form on top of a siltstone layer. Also, it should not be possible for these to be sandwiched between different layers of limestone.

Limestone is a type of rock that can form only in a marine environment, and both layers of limestone (#1 and #7) contain numerous marine fossils. Sandstone can be formed either on land or underwater. However, the sandstone (#4) in between these two layers of limestone could not possibly have formed underwater. It contains no fossils of marine organisms. Also, it contains numerous fossil tracks, including reptile tracks and also tracks from small arthropods such as centipedes and spiders. It also contains raindrop impressions. These cannot be formed underwater.

So the evidence clearly points to this: The land was submerged under water for some time. At some point after this, it became a sandy desert. After this, it was again submerged under water for a long enough time to form several hundred feet of additional limestone. I simply cannot figure out how this can be explained by a single global flood. I have searched the internet and cannot find even a single source that attempts to explain this.

If you can explain to me how the specific layers of rock found in the Grand Canyon area could have formed in the observed sequence by a global flood, then please do. Really, I mean it. I’m dying to understand this.

The Distant Starlight Problem

The history of the universe is recorded in the stars. Seriously. By looking into space, we can see events that occurred billions of years ago. Let me explain.

The sun is 8 light minutes from the earth. This means it is far enough away that light from the sun does not reach the earth for 8 minutes. If the sun were to suddenly explode, we wouldn’t even know it until 8 minutes later. By looking at the sun, we are looking 8 minutes into history.

stars in the sky

Stars as seen from Earth

The distances to about 100,000 of the closest stars to earth has been directly measured using basic trigonometry. These stars are distances of 4 to 1600 light years from the earth and represent less than a ten-thousandth of a percent of the stars in our galaxy. Studying these stars reveals a definite, reliable connection between color, brightness, and distance. Because the color and brightness can be observed for stars that are farther away, this connection can be used to calculate the distances to other stars in our galaxy. It turns out that some of the stars visible in the night sky (such as V762 Cas) are up to about 15,000 light years away.

But that is just in our galaxy. There are many other galaxies that are close enough for astronomers to be able to distinguish individual stars. Using the same method, they have determined the distances to these galaxies (such as NGC 7320, at 40 million light years). And this represents only a small percentage of all the galaxies out there. Most of them are much farther than that.

the Andromeda galaxy

The Andromeda galaxy, approximately 2.5 million light years from earth.

So when we look at a galaxy that is 40 million light years from earth, we see it as it was 40 million years ago. This presents a problem for the young-earth model. How can we see a galaxy as it was 40 million years ago if it didn’t exist 40 million years ago?

I have often heard it suggested that God could have made the light in transit so that we could see it immediately. However, this explanation has a very big problem. We do not just see constant streams of light, but we see events being communicated in that light. For example, we have seen stars exploding (such as SN 2008D). If we observe the death of a star in a beam of light created in transit, then we are seeing a star that never really existed, and God had encoded in a beam of light the history of an event that never actually took place.

Over the course of many years, various people have attempted to create scientific models that can explain how we can see these stars without requiring the belief in a universe that is billions of years old. To date, nobody has succeeded in creating such a model that is compatible with the observed properties of the universe.1 In fact, the very proposition of a young universe that obeys general relativity and in which distant starlight is visible can mathematically be proven impossible.2

However, the inflationary big bang model does a very good job at explaining the observed properties of the universe. It is consistent both with general relativity (which has itself withstood rigorous testing for almost a century) and with observational data.3

So what is the most obvious explanation for light being visible from stars billions of light years away? The universe is billions of years old.

[1] Perhaps the most well-known model in the young-earth creationist community is one that has been proposed by Dr. Russell Humphreys and that purports to solve the distant starlight problem in the context of a young universe. However, this model fails on a number of counts, which include misapplication of known laws of physics and lack of conformity with observed properties of the universe. See reference below for details.

[2] Ross, H. (1999). The Unraveling of Starlight and Time. Retrieved from http://www.reasons.org/articles/the-unraveling-of-starlight-and-time

[3] Although there is one discrepancy (the horizon problem) between observation and the original formulation of the big bang model, this problem has been solved by the inclusion of an initial period of rapid expansion (inflation) in the model. This inflationary hypothesis has recently been validated by the discovery of the gravitational waves that it predicted.