What is carbon-14-dating and how reliable is it?
Anything that was once alive or that was produced by a living thing can be dated by using the radiocarbon method of dating. This method, which received widespread attention in connection with the Dead Sea Scrolls, relies on the fact that all living things take in carbon, some of which is very slightly radioactive. But just how reliable is this method?
To hear some people tell it, scientists have nearly absolute confidence in the dating methods they use. When their dating methods say that something lived 30,000 years ago, they sound certain. And on the basis of these methods, many scientists announce that the Bible's record of history is not accurate. But that's not really how it is when scientists are working in their labs.
To understand how the C-14 clock works and what processes are involved, let us consider the egg-timer. By tipping the glass when the egg starts cooking, one learns when three minutes are up and the boiling should be stopped. One assumes that there is enough sand in the timer so that it takes three minutes for it to move from the top of the glass to the bottom of the glass. One also assumes that all the sand is in the bottom of the glass when one turns it over.
How does a scientist date a rock or a bone? He must look for something in the bone which disappears over time, as the sand disappeared from the top chamber of the egg timer. The disappearance must take place at a known and measurable rate. If the scientist can find out how much of this material was in the bone when the animal died, and if he knows how fast it disappears, and if he can measure the amount still left in the bone, he has something like a natural hourglass. Carbon-14 is used as just such a substance.
Carbon is one of the most important atoms in the living system. Carbon is present in proteins, fats and carbohydrates – the three basic foods. Carbon is found in all of our cells, including bone cells.
Carbon atoms such as we have in the living body are two kinds. Most of the carbon atoms are of the C-12 type. C-12 does not disappear, because it is stable. A very small part of the carbon in our body is radioactive C-14, which does change to a nitrogen atom. C-14, thus, disappears, like sand running through the hourglass.
The beta rays given off when C-14 changes to C-12 can be counted with a counting machine such as the Geiger counter. If many counts per minute (beta rays), are measured, high radioactivity and, therefore, much C-14 is present. If there are fewer counts per minute, there is not much C-14 in the bone.
If all bones have about the same amount of C-14 at the moment of their death, then the scientist can use the C-14 test as something like an hourglass.
Since carbon comes from the air, does the amount of carbon-14 in the air remain constant? Much of the carbon in the air is C-12, but a small amount of it is C-14. The plant, animal and human will each have about the same ratio of C-14 to C-12 as does the air. The next question is: Where did the air get its C-14?
C-14 enters the air by the action of cosmic radiation. Cosmic rays enter our Earth's atmosphere from outer space. When cosmic rays enter the atmosphere, they cause "scatter radiation," which consists of little particles called neutrons. A moving neutron is a high-energy particle which performs an interesting task. A nitrogen atom hit by one of these neutrons changes into a C-14 atom and ejects a protein. If a moving neutron enters a nitrogen nucleus, a proton comes flying out, and the nitrogen atom is changed to an atom of C-14. Thus, C-14 forms from nitrogen in our atmosphere.
The constancy of C-14 in our atmosphere depends on the cosmic rays coming into the atmosphere at the same rate. But the cosmic ray bombardment changes moment by moment, day by day and week by week. Such activity as sun spots or solar storms will affect the cosmic radiation. Some of the scientists who date by C-14 claim these are only small fluctuations and would have no overall effect.
But if there can be small fluctuations in the amount of the C-14 produced in the atmosphere day by day, then there could have been greater fluctuations in Earth's history. Let's take a look at the early Earth.
What might such changes in the atmosphere mean for dating studies? Let's consider the Flood and use what is called the "canopy theory." There is some evidence for a canopy surrounding the Earth before the Flood. The canopy would probably not stop all the cosmic rays themselves, but a good deal of the scatter radiation would be reduced. It would act as a shield. Thus, there would be a few neutrons and fewer C-14 atoms formed. Most of the carbon before the Flood would then be C-12.
Suppose the scientist doing the dating did not know about the Flood. He would give his bone a "date" of 15,000 to 30,000 years because of the very low C-14. He would do so because he believed all bones contained the present amount of C-14 when they died. He would give this bone a false date because of a false assumption. If the ratio of C-14 to C-12 was much less in the past for any reason, then false dates would be given to such fossils.
In recent years, many scientists have adopted a policy of refusing to trust radiocarbon dates which have not been tested by a second method. In 1966, scientists found, among some fragments of mammoth and bison bone in the Yukon Territory of Canada, a sharpened hide scraper made of caribou bone. This was clear evidence of man's activity, so they wanted to find out how old the bone scraper was. Radiocarbon dating told them it was 25,000 to 30,000 years old, placing it 20,000 years before man arrived in North America. Twenty years later, using a nuclear accelerator, another scientist tested the bones using a different method, and dated the bones not at 25,000 or 30,000 years old, but at only 2,000 years old!
Professor Robert Whitelaw was a leading creationist expert on carbon dating. The method itself was invented in the 1950s by W.F. Libby, a committed evolutionist. Dr. Whitelaw began studying carbon dating results in the 1960s and reviewed over 30,000 carbon-dating results. Dr. Whitelaw pointed out that Libby knew, from his own research, that carbon-14 dating proved that the Earth was only a few thousand years old. But Libby rejected this result as being contrary to his religion. When carbon-dating information is adjusted to fit Libby's own data, carbon-14 dating demonstrates that there was a world-wide cataclysm which destroyed all life at just about the time given in the Bible for the great Flood. Carbon-14 also shows that all living things appeared at about the same time.
When God's Word tells us about day and dates, we can trust His Word to be accurate. The Bible is not only a higher authority than any of man's schemes, it has always proven to be unerringly accurate, even when it speaks about history and science.