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The Age of the Earth

Many theologians have said we cannot accept Genesis because it does not agree with what scientists tell us. Before we accept this viewpoint, let us look closer and see what scientists are actually saying.

Picture in your mind a burning candle. It is six inches and burns at the rate of one inch per hour. My question: How long has this candle been burning? It will burn for six hours more, that is true. But it cannot be determined how long the candle has been burning unless one small insignificant fact is known -- how long was the candle when it was lit? If it were 100 miles high it has been burning for a long time. If it were 10 inches high and is now six inches, burning at the rate of one inch per hour it has been burning for four hours. But we do not know its size in the beginning, so how long has the candle been burning?

This candle illustrates serious problems implicit in various dating methods used to determine the age of the earth. Sometimes we get the impression from school books and the news media that when a scientist picks up a rock he can immediately tell how old it is. But instead, the scientist examines the rock using various assumptions. Several of the principle dating methods used in determining the age of rock depend on the slow transformation of the elements uranium to lead or thorium to lead. To explain how these methods work. let us assume that we have found a rock which was pure uranium. There are no rocks of pure uranium, but we are going to assume so for our experiment. If we are to determine how old this particular rock is we must first know a few things about uranium. Uranium has a half-life of 4 1/2 billion years. What does that mean? It means that if we find a rock of pure uranium, in 4 1/2 billion years half of that rock will change into another element, lead. This is called a radioactive decay process. So in 4 1/2 billion years our rock will be half uranium, half lead. If we wait another 4 1/2 billion years, half of the remaining uranium will change to lead, leaving us with one-quarter uranium and three-quarters lead. Half of any given amount of uranium will decay or change into lead in a 4 1/2 billion year period. That is the half life of uranium.

Based on that, we find a rock, determine how much uranium is present, how much lead is present, and we can therefore determine how old that particular rock is. But notice the uncertainties. Return to our candle illustration again. As the candle burns, scientists can make guesses, although in science such guesses are called assumptions, to determine how long the candle has been burning. These assumptions need to be made in order to answer our question. As the candle burns it gives off an amount of carbon dioxide. It would be relatively simple to measure all the carbon dioxide in the room and therefore assume it came from the candle. This would help to determine how long our candle has been burning. Any problems? We must assume that the people in the room watching the experiment are breathing and as they breathe they give off carbon dioxide. Carbon dioxide is also naturally present in the room This is unfortunate for those doing the measuring because carbon dioxide from breathing is exactly the same as the carbon dioxide in the room which is the same as carbon dioxide from a burning candle. There are three different sources for the carbon dioxide. If I assume all the carbon dioxide comes from the candle, I may assume the candle was 620 million miles high and burning 4 1/2 billion years.

A similar problem exists when a rock containing uranium is dated. We can find the amount of lead present, even the various isotopes of lead, lead 206, 207, 208, and know that they came from various isotopes of uranium, or in the case of lead 208, from thorium. We can determine how much uranium is present and how much lead. If we assume all of the lead came from the parent element uranium we will calculate a certain age. However, that may or may not be the actual age. Why? Lead is naturally present everywhere in the crust of the earth, lead that cannot be traced to radioactive decay. How, then, can lead be a dependable indicator of age?

Lead 208 is the end product of the thorium-lead dating system. Thorium is called the parent and lead the daughter. If a rock contains lead 208 and this is a consistent system, thorium should also be present; but rocks from certain mines in Katanga, Africa, and other mines in Canada, contain lead 208 naturally present with no thorium present. This requires an entirely different means of explaining where the lead 208 came from.

Dr. Melvin Cook (Ph.D., Chemistry from Yale University) postulates that it came from neutron capture, although there are other excellent ways of explaining this situation. According to Dr. Cook, the uranium-thorium-lead clock points to zero, (meaning the hands of the clock have not moved). If all these various isotopes of lead can be accounted for on the basis of neutron capture then uranium-thorium-lead systems do not provide a very reliable dating method. If we erroneously assume that all the lead came from uranium or thorium we get an age which is erroneous, an age that is too old. In reality, we do not know exactly where that lead came from. We are assuming it came from a decay process, but that basic assumption has been shown to be false in certain specific instances. Therefore an age of 4 1/2 billion years must also be false and the alleged earth age of 4 1/2 billion years cannot be relied upon.