Evidences for Evolution, Part 1: An Ancient Earth

Bookmark and Share

May 31, 2010 Tags: History of Life

Today's entry was written by David Kerk and Darrel Falk. Please note the views expressed here are those of the author, not necessarily of The BioLogos Foundation. You can read more about what we believe here.

Evidences for Evolution, Part 1: An Ancient Earth

A literalistic view of Genesis causes many evangelicals to believe that the earth is less than ten thousand years old. Christian children and young people frequently grow up being told that the earth is young and that evolution is a lie. The most popular science/religion web-site by far according to Alexa ratings is “Answers in Genesis”, and its museum, dedicated to a young earth perspective has attracted over 1 million visitors since its opening two years ago. Since evangelicals, we believe, are correct about so many other all-important issues, how can we be so certain that so many are so wrong about this one? Consider sending this link to a young earth friend or pastor. Some think that the science behind this matter can’t be trusted. Nothing could be further than the truth.

The beauty of the scientific process is its inherent scepticism. (See "What Scientists Do" by Steven Benner). If there is only one way of reaching a conclusion, the scientific process requires the scientist to remain highly sceptical. The only conclusions in science which are widely accepted are those which are supported by multiple, reinforcing lines of evidence – “all roads must lead to Rome”. If there is even one scientific trajectory that seems to clearly lead off to Peoria instead of Rome (to use a recent analogy of Francisco Ayala), the scientific process demands that the scientist find out why. The scientist who does not retain an attitude of scepticism when there is only a single line of evidence, and particularly one who ignores other, conflicting lines of evidence, is on a stubborn trajectory of his own—a trajectory to failure. If the only reason for following the directions which “lead away from Rome” is a particular view of Scripture, then it is important to consider the possibility of human error. Biblical hermeneutics, after all, is a human enterprise just as science itself is. For example, John MacArthur in his current series on Genesis is human and is interpreting Genesis in his way just like the rest of us. He, wonderful pastor and shepherd that he is, interprets Scripture too. There is good reason to be quite certain that the interpretation he subscribes to is mistaken.

As Christians, we are called to follow Jesus. In so doing, Jesus said we are to love the Lord our God with all our heart, soul and mind—not just our heart and soul. Indeed if we close our mind, we are actually disobeying what Jesus said was the greatest commandment of all. So let’s not be shy about using those minds. Are there multiple independent ways of keeping track of time since the creation of the earth? If so, do each of those ways point to the same conclusion?

The best known method of calculating the age of material on earth depends on the well-established fact that certain elements in the earth’s crust are unstable and decay at a fixed rate that can be measured. (For an introduction to this topic see this BioLogos FAQ.) This instability functions sort of like a set of clocks that have been ticking through the eons of time. Indeed there are many types of unstable elements; there are many ticking clocks. Each of the various clocks tick at a different rate. The rate of each can be calibrated, and, with an amazing degree of consistency, all “clocks” point back to the same starting point: an ancient earth with rocks that are hundreds of millions and even billions of years old. This “ticking clock” technique is known as radiometric dating.1,2

There are other totally independent ways of estimating the age of material on earth. To appreciate how these work, perhaps we should start with shorter spans of time, which for human beings are much more readily comprehensible. Some of the fondest boyhood memories of one of us (DK) come from visits to the majestic California redwood forests. He especially remembers an exhibit of a section from a giant tree which showed the pattern of growth rings within it. It turns out that these rings accumulate in response to seasonal differences in rainfall and temperature, which in turn produces differences in growth rate. Fastened within this huge slab of wood was a series of tags, proceeding from the surface inward, demonstrating the dates of major historical events: the landing of the Pilgrims on Plymouth Rock; Columbus’ discovery of the New World; the Norman conquest of England, and so forth. It was possible to see in the yearly growth rings a history of what seemed then to be the very distant past!3

Growth layering processes are not restricted to trees. Many species of marine invertebrates accumulate calcium carbonate from their watery environment and incorporate it into some form of shell. Examples would be clams and corals. In fact, for these species, the variation in shell deposition occurs on a both a daily and a yearly basis, so an even finer counting of time periods is possible.4

Just as it is possible to count the rings in trees and correlate their age to known historical events in the past, it is also possible to count the banding patterns preserved in the fossils of marine organisms, and use this as a method to estimate their ages. Let’s see how it works.

Astronomical data, developed and analyzed over the past couple of centuries, has revealed that the rotation of the earth is gradually slowing down. This is due to the friction created daily by the moving tides on the earth’s surface, produced by the gravitational pull of the moon and sun. Furthermore, as the earth slows down slightly, some rotational energy is transferred to the moon, which alters its orbit slightly (its orbit is moving slowly away from the earth). The data leading to these conclusions range from analysis of ancient solar eclipses (whose dating allows the precise position of the earth, sun and moon to be determined) to bouncing laser beams off mirrors placed on the surface of the moon by the Apollo astronauts. For our purposes, what will be important is the slowing of the earth’s rotation. This predicts that the length of each day has been slowly increasing since the formation of the earth/moon system. The average increase in the day length is estimated at 2.3 milliseconds (.0023 seconds) per century.5,6 Hence as we examine events in the past, day length was shorter, by an amount that can be calculated. Ten thousand years ago, a day would have been .23 seconds shorter than it is today. If direct experimental estimates of day length can be obtained, they allow an estimate of the age of the material.

One way that such experimental estimates of day length can be obtained is through the periodic growth rings deposited in the shells of marine invertebrate organisms. Take for example a clam living in an intertidal environment. If the tide is in and the shell is open, it can readily absorb oxygen from water, use aerobic metabolism, and incorporate calcium carbonate into its shells. When the tide is out and the shells are closed, however, little oxygen can be absorbed, anaerobic metabolism is used, shell decalcification occurs, and organic rich material accumulates in the shell. This alternating pattern of shell deposition occurs on a daily basis, and is clearly visible in both shells from living and fossil clam species by microscopic examination. Furthermore, shells contain an identifiable mark resulting from the first freezing day of winter, and from the first really hot day of summer. Hence a yearly growth interval can be readily determined.7

When such data are analyzed for a number of fossil species, it is clear that the number of days these organisms experienced each year was higher than today. Given that, we have another clock - a totally independent way of measuring the age of certain fossils. So how well do clocks based upon radiometric dating agree with those based on measuring rings in certain sea shells?

As already mentioned, organisms living 10,000 years ago would have experienced shorter days, but they would only have been shorter by 0.2 seconds. Organisms living 1 million years ago would have experienced a day length that was 20 seconds shorter. If the earth really is very, very old, organisms living 465 million years ago, for example, would have experienced approximately 416 days per year, each day being about 21 hours long.7 Amazingly, shelled fossils in formations dated by radiometric clocks to be about 465 million years old show, by their banding patterns, that the days really were three hours shorter. In fact the two sets of clocks agree within 1 percent!

Another way such estimates of ancient day length can be derived is to look at the periodic patterns formed in fine silts in ancient river estuaries. The daily tides produce shifts in the mud, leaving a fine layering pattern, which is recorded in rock as these sediments transform into materials such as sandstone (such deposits are called “rhythmites”). Other shifts in the mud are produced over longer time intervals, including seasonal and yearly shifts. By counting the number of daily depositional layers per year, in a similar fashion to work with marine organism shells cited above, an estimate of ancient day length can be derived. One advantage of the rhythmite analysis method is that it can be applied to more ancient materials, in eras of the earth’s history when organisms suitable for shell analysis were scarce or non-existent. For example, radiometric analysis of certain rock formations in South Australia dated them at 620 million years of age. On this basis one would predict that the day/night cycles should have been about 20 hours long in these formations. Actual measurements of day length from the preserved mud banding patterns, although off from the expected by ten percent (estimated day length is 22 hours) is again consistent with the formation being hundreds of millions of years old just as the radiometric dating has predicted.8

In conclusion, there is data derived from three independent sources: the decay of radioisotopes, the growth patterns recorded in fossilized shells of marine organisms, and rocks containing tidal depositional material from river estuaries, which all agree on an ancient age for the earth. Furthermore, by a totally independent method it is also possible to measure the age of the universe as a whole and again it is billions, not thousands of years.

All of the roads in God’s book of Nature “lead to Rome” (i.e an ancient earth) - it is only mistaken human interpretation of Scripture that causes some of our precious brothers and sisters in Christ to end up in Peoria.

The next blog in this series can be found here.

Editor's Note: Dr. Kerk offers a further discussion of the age of the earth in the comment section of this post, beginning here. Dr. Kerk has also included the following graph:


1: Elementary principles of radiometric dating are discussed by Richard Dawkins. Dawkins, R. 2009. The Greatest Show on Earth: The Evidence for Evolution. Free Press, New York Pgs. 91-98.

2: Wiens, R.C. 2002. Radiometric Dating: A Christian Perspective. This is a more detailed but still highly readable account of radiometric dating, written by a well-qualified physicist who is also a professing Christian. It can be obtained from the web site of the American Scientific Affiliation: http://www.asa3.org/ASA/resources/Wiens.html

3: Tree ring dating (“dendrochronology”) is discussed by Dawkins, pgs. 88-91.

4: Dating using coral skeletal deposition is discussed by Jerry Coyne: Coyne, J.A. 2009. Why Evolution is True. Viking Penguin, New York. Pgs. 24-25.

5: “Tidal Acceleration”, Wikipedia: http://en.wikipedia.org/wiki/Tidal_acceleration

6: Stephenson, F.R. 2003. Historical Eclipses and Earth’s Rotation. Astronomy and Geophysics 44:2.22-2.27.

7: Zhenyu, Z., Yaoqi Z., Guosheng J. 2007. The periodic growth increments of biological shells and the orbital parameters of Earth-Moon system. Environmental Geology 51: 1271–1277.

8: Williams, G.E. 2000. Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit. Reviews of Geophysics 38(1):37-59.

David Kerk is Professor of Biology, Emeritus, at Point Loma Nazarene University. Dr. Kerk obtained his PhD in Anatomy at UCLA and is currently involved in bioinformatics research at the University of Calgary. He resides on Vancouver Island, in Parksville, B.C. Canada.
Darrel Falk is former president of The BioLogos Foundation. He transitioned into Christian higher education 25 years ago and has given numerous talks about the relationship between science and faith at many universities and seminaries. He is the author of Coming to Peace with Science.

Next post in series >

Learn More

Share your thoughts

Have a comment or question for the author? We'd love to hear from you.

View the archived discussion of this post

This article is now closed for new comments. The archived comments are shown below.

Page 19 of 19   « 16 17 18 19
usernametodd - #17082

June 9th 2010

Doesn’t Genesis 1:7-10 teach us that the heavens and the earth were created out of something that was already there?  A whole “new” creation out of something that was already there?  It seems to.  This article elaborates further.


Gregory - #17085

June 9th 2010

Merv, we agree the Earth is ‘old’ & more wrt Christianity!

R. Hampton brought up Pope Benedict XVI, backed by the Vatican’s Pontifical Academy of Sciences & Gabriel called this merely ‘argument from authority.’ I’d say that is disrespectful & shows ignorance of much work behind B16’s statement.

BioLogos is designed to reach out to fundamentalist, evangelical Christians in the USA who don’t trust & sometimes have little respect for & even fear of science & who protest mainly based on the Holy Bible that ‘evolution’ cannot be true, the Earth is young & other related fallacies. It is thus sad to see there has been *no progress* with Gabriel to openly consider scientific arguments.

“I don’t want to argue on the basis of science” - G. Powell

Why then come to BioLogos not wanting to discuss science, which explicitly engages with the sciences & seeks integration of science & Christian faith? Just to preach?

I have not mocked the Gospel explanation, Gabriel. I have mocked your presumptuous, haughty attitude & refusal to consider evidence by honourable, hard-working Christian scholars & scientists.

Still, I wish you best at seminary & hope the experience & teachings there will help to open your mind & heart.

Philip R - #17087

June 9th 2010

Gabriel said (16990) “Let me encourage you to not superimpose 21st century evolutionary constructs on Scripture and interpret Scripture on its own accord.”

Firstly, I do it the other way around: i superimpose scripture on 21st century “evolution”  (i’d actually restate this as current scientific thinking). We have to meet people where they are. We have to test everything. We live in the world and should always demonstrate that the scripture is current and relevant! Imagine if Christ just spoke the old testament to people of his time without using parables and analogies of the time he was in. People have different circumstances, experiences and means of understanding. Its not about conformation, its about confirmation. The Pharisees at the time of Christ did not want to listen to his reasoning and application of the scriptures, as it was presented in such a current, engaged way. He met with the lowest and highest in society. There is nothing new under the sun (Eccl 1: 9,10). Sorry for any confusion - wasn’t my intention.

merv - #17093

June 9th 2010

Thanks Greg, Philip, & others for your interactions here as well.  I try to avoid mockery of any kind, Greg, even if it seems to you that such is what is merited.  On many occasions, I have earned it, but somebody better than I patiently put up with me and persisted.  Their scorn would probably have pushed me away, but their patience yielded fruit. 

Taking Gabriel’s lead, I may wean myself just a wee bit from this thread to pay more attention elsewhere, but that doesn’t mean I won’t check back here over the next days in case you want to keep discussing anything.

Interesting thought about what is superimposed on what, Philip.


merv - #17094

June 9th 2010

p.s.  I know a thread is getting too long when my ancient dial-up connection takes most of a minute just to get all the text loaded.

And Gabriel,—in case you were checking back here to read any last comments, enjoy the water at Tahoe & remember to leave any electronic devices locked away in cabin or car so that the siren call of ‘blog world’ is at least somewhat muted.  Wishing you God’s blessings.


defensedefumer - #17096

June 9th 2010

Gabriel Powell,

Thanks for the interaction. Even though we have our differences, thanks for enlightening me on your position. I apologise if I have been rude in some of my replies.

To Biologos,

Thanks for providing a platform for interaction for people with differing views on science and faith.

To everyone else:

Keep up the interaction!

John VanZwieten - #17099

June 9th 2010


Are you really equating your blog post with “the gospel, the whole gospel, and nothing but the gospel”?

Does one have to agree with everything you wrote there?  If you think that, it seems contradictory to your paragraph:

“What does He require of us? To repent and believe. Repentance simply means turning away from sin, and turning toward God. It means not living the way we want to, but living the way he wants us to (Isaiah 55:7). So we must repent. And we must also believe. Romans 10:9 says, “If you confess with your mouth Jesus as Lord and believe in your heart that God raised him from the dead you will be saved.” We must believe the good news that the Bible teaches. Put another way, we must believe in Jesus and submit our lives to him.”

So can one agree with that paragraph but not some of the others and still be a Christian?

Also, I don’t see anything in your post about the “kingdom of heaven” which seemed a pretty important part of the gospel as preched by Jesus.

Biologos is actually a nice place to interact with believers from various Christian traditions.  Since we have Christ in common, maybe we can allow one another to speak from those traditions with freedom, and learn from each other.

Dave - #17313

June 13th 2010

I realize I am jumping in late to very lengthy discussion, but might I suggest a very interesting article discussing the times of the Creation that brings us all back to a basic level of understanding of what the book of Genesis said when it was written:


Martin Rizley - #22102

July 16th 2010

Dr. Kerk,  The most that science can say (based on its inherent skepticism about the ‘finality’ or ‘absolute’ character of human knowledge) is that many independent lines of evidences interpreted on uniformitarian principles concur in suggesting that the earth is very old (a YEC like Todd Wood would agree with that assessment).  That is the APPEARANCE of things, from the standpoint of naturalistic science, as it makes various calculations from the existing data.  However, to move from saying the world APPEARS old to saying the world IS as old as it appears involves an epistemological leap that is thoroughly grounded in metaphysical (even religious) assumptions about reality and how human beings arrive at a fixed, unassailable knowledge of the world around them.  Now, in a Christian worldview, doctrines of the faith are matters of certain knowledge, for they are based on direct propositional revelation from God, whose knowledge is infinite, and who cannot lie.  Since God cannot lie, we can believe what He says with dogmatic certainty as unassailably true (continued).

Martin Rizley - #22105

July 16th 2010

But scientific knowledge by its very nature is always provisionsal (never dogmatic or final), because it is based on interpretations of currently available data by finite human beings who are seeking to understand the world that surrounds them within a particular ideological framework—it is a knowledge forged out of finitude, and therefore, always open to revision or change.  By contrast,  the doctrinal assertions of Christianity are based on the verbal declarations of an infinite God who cannot lie or err in what He asserts.  They are not open to revision or change.  Let me ask you—do you believe in evolution as a dogma, or as a provisional interpretation of the evidence based on what seems (to your mind) to be the most reasonable interpretation of the evidence available?  Do you make any distinction between “dogmatic” beliefs that you hold based on God’s propositional revelation in Scripture—beliefs which are non- negotiable—and other beliefs that you hold “provisionally” (such as your belief in evolution)—that are subject to change or revision, if further data arises or new interpretations of the data are proposed that have greater “explanatory power”?

Page 19 of 19   « 16 17 18 19