Can We Really Know the Earth is Billions of Years Old?

Can We Really Know the Earth is Billions of Years Old?

Kids love dinosaurs. They are big and scary and growl-y and dangerous. Proud parents beam as their precocious little paleontologists recite their wealth of dinosaur facts. The trouble starts when the little paleontologists learn that dinosaurs roamed the earth between 65 – 230 million years ago, a timeline that is hard to squeeze into an earth that is only 6,000 years old.

That’s when dinosaurs really become dangerous.

It wasn’t until the 20th century that a “young earth” (between 6,000 and 10,000 years old) became a widespread belief among evangelicals. A young earth created many problems: how do you reconcile apparently ancient events with a fairly short earth history? To make the math work in the case of the dinosaurs, dinosaurs and humans had to coexist. Maybe not exactly in the way they did in the town of Bedrock, but close.

fred and dinosaur

Apologetics Press (AP) is a prolific source of Young Earth Creationist (YEC) literature. An AP published science book for children, Dinosaurs Unleashed: The True story About Dinosaurs and Humans, includes illustrations of men fighting a vicious T-Rex, baby dinosaurs climbing a ramp to Noah’s Ark, and an idyllic scene of a young girl and her dinosaur pet. Not exactly Fred and Dino, but not too far from it.

               pet dino           dinos on ark           trex

When the age of the earth is a tenet of faith, conflict arises when scientific evidence doesn’t fit the faith-required parameters. The most common response is to somehow make the evidence fit the belief.

All scientific evidence points to an earth and a universe of immense age:

There are no scientific arguments of any consequence that point to the earth being just a few thousand years old. Not one isolated piece of nontrivial data, in any form, points in this direction (p. 54).

How Old is the Universe? How Do We Know?

The age of the universe is around twelve to fourteen billion years. Scientists arrived at this number because several unrelated lines of evidence converge on that number. Let’s look at two lines of evidence:

speed limit of light The speed of light: Light travels 186,000 miles per second. Our sun is 93 million miles away. When light leaves the sun, the light has to travel 93 million miles before we can see it. If you do the calculations, you will find that it takes eight minutes for light from the sun to reach the earth. When you see the sun, you are actually looking back in time. If the sun went dark, we would not know for eight minutes.

Our sun is relatively close to us, but other stars are unimaginably further away. They are so far away that it takes millions, even billions of years for the light from these distant stars to reach us. One way to estimate the age of the universe is to calculate how long it would take for the light we see from distant stars to reach us. The fact that we are seeing light from stars so far away tells us the universe  is billions of years old.

The Big Bang: Edwin Hubble (for whom the telescope was named) discovered in 1928 that virtually all of the galaxies in the universe are moving away from us. If the universe is expanding, it must have been smaller in the past. And since the universe is not infinitely large, there must have been a point in time when the expansion started from a single point – The Big Bang. (This is where you start to sing the opening lines of the sitcom Big Bang Theory to yourself: “…the whole universe was in a hot dense state then nearly fourteen billion years ago expansion started. Wait!”).

We know how fast the galaxies are traveling. The speed of the galaxies is measured in the same way a police officer measures the speed of your car – using radar to measure the Doppler effect. Knowing the rate of expansion and the average distances between galaxies, we can calculate how long the universe has been expanding from the starting point until now.

What if (as Young Earth Creationists suggest) God created light “in transit”?

Then what we see is not what actually is.

What about supernova – exploding stars – that are millions of light-years away? Those stars never actually existed according to YEC reasoning. Of course God could have created a universe with the appearance of age. God could have created everything ten minutes ago and placed a lifetime of memories in our brains.

Or, stars, galaxies, and supernova appear to be billions of years old because…they are.

How Old is the Earth? How D0 We Know?

As with the universe, the age of the earth has been determined using multiple, disparate lines of data that all converge at the same number. Here are some of the ways the age of the earth is determined:

Tree rings: We can determine the age of a tree by counting the rings on their trunks. The oldest living things on earth are six-thousand-year-old bristlecone pines in the Sierra Nevada. Dead trees lying nearby are almost twice as old.

Lake beds: Lake beds accumulate sediments according to the season: minerals in spring and pollens and plant materials in fall. Lake beds as old as 35,000 years have been found.

Ice rings: Similarly, glacial ice has layers that indicate changes in seasons. Ice cores have been drilled in ice as old as 740,000 years.

Using the simple skills of visual observation and counting, tree rings, lakebeds, and ice cores place the earth well past the 6,000 to 10,000 year age proposed by Young Earth Creationists. Using patterns in the orbit of the earth and patterns of magnetic field reversals, we find dates for the earth going back 30 million to 170 million years (Language of Science and Faith, pp. 62-63).

Dating methods for the way way back – radioactive clocks: In the nucleus of an atom are particles called protons and neutrons. Usually an atom will have equal numbers of protons and neutrons, and all is happy and stable in the atomic world. Sometimes, however, there are extra neutrons in the nucleus of an atom, making the atom unstable. Atoms will “throw off” the extras protons to form a more stable atom.

For example, atoms of uranium-235 are unstable. Uranium-235 will throw off neutrons until it has changed into a more stable element, lead-207.

We know how long it takes for unstable uranium to decay into stable lead. When we want to date a rock containing uranium-235 and lead-207, we can measure the ratio of uranium-235 to lead-207 and determine the age of the rock. Using the uranium-lead clock, the age of the earth is about 4.566 billion years old.


The heavens declare the glory of God;
    the skies proclaim the work of his hands.
Day after day they pour forth speech;
night after night they reveal knowledge

(Psalms 19:1-2)

Everything in the cosmos pours forth speech and reveals knowledge.  Do you believe the speech is true? Do you believe the knowledge is Truth? Do you believe that the cosmos actually is what it reveals itself to be?

Three Kinds of Creationists

Young Earth Creationists: Young Earth Creationists (YEC) believe that Genesis is a scientific and historical account of origins. Adding up genealogies (the begats) and assuming seven literal 24-hours days of creation, YEC conclude that the earth is less than 10,000 years old.  These assumptions are based almost entirely upon English translations of the Old Testament. Many scholars in Hebrew, Old Testament, and ancient cultures insist that the YEC position is not even close to what the text of Genesis is saying.

Old Earth Creationists:Old Earth Creationists (OEC) also believe that Genesis is a scientific and historical account of origins, but they accept scientific evidence for the age of the earth. Although OEC allow for an earth that is billions of years old, OEC believe that living things were created by direct and separate events – no natural processes were involved and they reject evolution.

BioLogos: The view of the authors of The Language of Science and Faith and many Christians who want to be biblically based and scientifically accurate is BioLogos: God’s creative activity is executed within the natural order (Language of Science and Faith, p. 72), using and respecting established natural laws.

Reading Genesis

A literal reading has not been widely accepted as the only way to interpret Genesis for most of the history of the church. Important Christian writers like Origen, Augustine, and Aquinas, although all lived in a pre-scientific time, did not support a literal reading. Even William Jennings Bryan, famous for arguing against evolution in the Scopes trial, did not believe in a young earth.

The Genesis Flood, published in 1961, was wildly popular in evangelical circles and was responsible to a great extent for defining the terms that still exist: serious, Bible-based Christians believe in a young earth and special creation. Deny any aspect of a literal interpretation, and your faith is suspect.


In an auspicious courtroom in 1633, one of the major players in the scientific revolution faced an inquisition by Church authorities. Galileo Galilei was on trial for heresy. Galileo wrote and taught that the sun, not the earth, was the center of the solar system – an obviously false idea because it is directly contradicted by the clear teaching of scripture: The Earth Does Not Move.

After all, Psalm 104:5 says:

He set the earth on its foundations; it can never be moved.

Although Galileo eventually recanted (with fingers crossed behind his back) rather than face the full penalty of the Inquisition, it wasn’t long before his clearly observable astronomical discoveries were widely accepted by Christians.

New science discoveries, new evidence, new data – Christians were compelled to reexamine a biblical text – and faith survived.

Twenty-first century Christians are faced with the evidence that much of life lived and went extinct before humans came along, with Darwin’s discoveries, with evidence of the Big Bang, and with the genetic evidence that all species are related.

These are our Galileo moments.

This series is a chapter by chapter discussion of The Language of Science and Faith by Karl W. Giberson and Francis S. Collins, with commentary and my observations.


I believe that the heavens declare the glory of God.
I believe that day after day the cosmos pours forth speech and night after night the cosmos reveals knowledge.
I trust that the evidence and knowledge that is revealed is true because the Creator of the cosmos is Truth.

One response

  1. Pingback: Science or Faith – Do We Have to Choose? « Janet K. Ray

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