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Radiometric Dating

Q.     How do you explain the results of radiometric dating which say the earth is billions of years old, and the Bible's account of creation?   

A.     The age of the earth as presented in the Biblical account of creation, and the age of the earth as calculated using radiometric dating are vastly different (thousands of years compared to billions of years).  The key issue one must understand to explain this apparent contradiction is that scientists must use some assumptions in order to interpret the measurements radiometric dating techniques use when assigning an age to a rock.  Those assumptions are: 1) the starting amount of the decaying radioactive material being measured, is known, and 2) the rate of decay of the radioactive material being measured is an absolute constant, and nothing can alter that rate.  

An easy illustration to show why these assumptions are critical for radiometric dating is an ice cube.  Let’s say you have 1 pound of ice at 32 degrees, and you have measured hundreds of times that at 33 degrees, it takes 24 hours for the entire 1 lb. of ice to melt into 16 ounces of water.  Here then is an experimental question.   At an unknown time some ice was put into a room; you are asked to determine when the ice was put in the room.  The temperature in the room is 33 degrees.  You weigh the ice, it weighs  1/2 lb.; and you measure the water, there are 8 ozs.  You then are pretty confident that 1 lb. of ice was put in the room 12 hours ago.  Would you be right?  Well—IF  no one had added to, or taken away any ice from the amount ( 1 lb.) you found in the 33 degree room, and IF  no one had added to, or taken away any water from the amount (8 ozs.) you found in the 33 degree room, and IF  the temperature in the 33 degree room was constantly 33 degrees the entire 12 hours—your calculation that the ice was put in the room 12 hours ago would be correct.  

What assumptions did you have to use in order for your measurements and calculations to be interpreted correctly?  They were that you knew the starting amount of ice and that you knew the rate the ice melted.  The problem is, however, you did not watch the ice from the time it was put in the room, until you measured it 12 hours later.  So if someone told you that when they put the ice in the room the temperature was 50 degrees, and then they set the thermostat to 33 so the room would cool down, your interpretation of the measurements you made would be wrong.   The ice was not in the room 12 hours, it was there for a shorter period of time, because it melted faster than you assumed.

The problem with radiometric dating is, if the assumptions which must be used to date the object are wrong, the interpretation of the measurements will be wrong.  Usually the scientists doing the measurements are assuming they know, for example, how much C14, which is radioactive carbon, was in the organism when it died (C14 dating is used to determine the age of things that were once alive.)  Where did that radioactive carbon come from?  It came from the atmosphere the organism lived in when it was alive.  All the carbon in living things ultimately comes from the CO2 in the atmosphere.  And how do scientists know how much radioactive carbon was in the atmosphere in the past?  They assume it was the same amount as what is in the atmosphere today.  However, if, the organism being dated lived in an atmosphere with less radioactive carbon in it than what is in today’s atmosphere, they would date that sample as being older than it is.  Why? Because they would interpret the small amount of C14 left in the sample to be a result of how long it took to decay, when actually, the small amount was due to the fact that the organism, when alive, had less radioactive carbon in it to begin with.  So their measurements were OK, but one of their assumptions was incorrect.  

Similarly, if the rock layers which God created in the beginning contained different levels of radioactive materials than what most scientists assume the various types of rocks begin with, when they are formed, then the measurements used in radiometric dating will be interpreted incorrectly.  If conditions, when radioactive materials are subjected to them, cause the rate of decay of those radioactive elements to vary from what we measure them now, the measurements used in radiometric dating will be interpreted incorrectly.  Of course someone may object to the assumption that God created the earth.  And there lies much of the reason why it is very difficult to come to an agreement on these things.  The assumptions are very different.  

As a person who readily admits his assumptions, i.e. the original  Word of God accurately reveals earth's natural history in the book of Genesis, and the account we have today is virtually the exact word-for-word transcription of the original, I question the assumptions generally used by scientists to perform radioactive dating of rocks and other artifacts.  But having said that, I think there are plenty of reasons to question their assumptions based not just on our conflicting assumptions, but also on contradictory scientific data which those scientists produce when trying to determine the age of the earth.  

One example of evidence that contradicts the standard “deep time” age assigned to rocks by “old earth” scientists when interpreting radiometric dating results comes from the radioactive decay of uranium.  A by-product of uranium decay is helium.  The unstable nucleus of the most common isotope of uranium, U-238, emits an alpha particle—2 protons/2neutrons—which is the nucleus of a helium atom.  And an alpha particle is emitted 8 times during the process of U-238 decaying into lead 206.  When we measure how long it takes for U-238 to undergo the first step of decay into thorium  234, the half-life appears to be 4.5 billion years!  (Of course, we’ve never sat around and watched 1 gram of U-238 turn into  1/2 a gram of U-238 and  1/2 a gram of Th-234, but by observing what we can, a 4.5 billion year half life is our best estimate.)  

Scientists then measure the amounts of U-238 and Th-234 as well as the other products of the decay of U-238, and based on the amounts of the isotopes in, for example, a piece of granite, they determine the granite to be 1 billion years old.  As the U-238 decayed it was also emitting helium atoms, and we can also measure the amount of helium still trapped in the granite.  What is found, however, does not seem to fit with the age assigned to the granite, because there is a large amount of helium still in the rock.  If indeed the granite is hundreds of millions of years old, it seems like the helium surely would have diffused out of the rock long ago.  And in fact, the rate of diffusion of helium through granite was tested by “young earth” scientists as part of the RATE (Radioisotopes and the Age of The Earth ) Project in 2005, and shown to be relatively rapid, confirming the proposal that there was way too much helium still present in granite that was supposedly 1 billion years old!  

How can this observation be explained?  Perhaps during the period of time when the granite was molten, such extreme conditions caused accelerated decay of the U-238, until the material cooled at which time the decay rate decreased to what we observe today.  This explains how there then is still so much helium in the granite; the process of the helium diffusing out of the rock has simply not been taking place that long.

Another observation related to the release of helium by uranium decay is the amount of helium in the earth’s atmosphere.  Based on the rates of production of helium from radioactive decay, and the escape of helium  from our atmosphere, there should 2000 times more helium in the atmosphere than there is, if indeed, the earth and its atmosphere is about 4.5 billion years old.  However, if the earth and its atmosphere is simply not that old we would expect these much smaller amounts of helium because the whole process of radioactive decay has not been taking place that long.

The evidence from dinosaur fossils also calls into question the dates assigned to rocks using radiometric dating.  The evolutionary explanation for the extinction of dinosaurs states the event took place 65 million years ago.  That time frame is based on the radiometric dating of the rock strata in which they find dinosaur fossils.  However, we are now finding more and more dinosaur fossils which are not completely fossilized; soft organic tissue including blood vessels, blood cells and connective tissue is present in many specimens.  Is it reasonable to simply assume that these tissues must have avoided fossilization or degradation while lying around in the earth for a minimum of 65 million years, or should the interpretation of the data from the radiometric dating of the rocks the fossils are found in be questioned?

Purely from a scientific perspective, these and many other discoveries give reasons to reject the estimates of the age of the earth using standard radiometric dating techniques and the assumptions used to make them.  However, even more important is the fact that the age of the earth determined by standard radiometric dating techniques is incompatible with the clear revelation and meaning of Scripture.  It is “nice” to have scientific evidence to support one’s faith in the Word of God, but even when it seems that there is no apparent scientific evidence to support some specific claim in the Bible, Proverbs 3:5-6 is a great reminder concerning how to handle the question.  “Trust in the Lord with all your heart, and do not lean on your own understanding.  In all your ways acknowledge Him, and He will make your paths straight.”

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