Interfaith Talk @ MMU Melaka

By Assoc. Prof. Dr. Living Lee Chai Peng
(For Interfaith Talk 4 at Multimedia University, Malacca Campus on 8 January 2003)

If you ask a natural scientist “how old is the Earth?”, you will get the answer about 4.5 or 4.6 billion years old.

Young age creationists, however, will tell you that it is about 6000 years old and no older than 10,000 years maximum. Who are we to believe? Therein lays the problem facing many a Christian interested in Science and the Bible. The young-age creationists have made it an either/or option – you either believe in the six literal days of creation and a young earth or you belong to the other camp of theistic evolutionists, long-age creationists and atheistic or agnostic evolutionists. Are these two the only options opened to the Christian who believes that the Bible is the inerrant inspired Word of God?
How do mainstream scientists date the age of the earth? They do so by dating meteorites which have experienced no major geological changes in their compositions other than by radioactive decay of unstable isotopes since their birth together with the Sun and the planets from the same interstellar cloud. Radioactive potassium-40 decays to argon-40 with a half-life of 1.3 x 109 years. Assuming all the 40Ar present in these meteorites have been derived from the decay of potassium-40 their ratios indicate that the potassium to has been decaying for the past 4.5 to 4.6 billion years. Similar ages have also been obtained from the decay of rubidium-87 to strontium-87 in some lunar rocks. In comparison, minerals and rocks from geologically active planets like the Earth in which the composition is continually altered physically and chemically give widely varying ages from more than 4 billion years to very recent ages.

What is radiometric dating? The use of radioactive elements and the products of their decay to act as geological clocks to date rocks is based on the principle that each radioactive element decays exponentially at its own nearly constant rate, meaning, no matter how much parent element was present at the start of the process, only half of that amount will survive after a certain time interval known as the half-life of that element. The most commonly used radioactive isotopes for dating rocks are given in Table 1.

Table 1 : Radioactive isotopes commonly used for dating

By measuring the amount of parent material and comparing it to the amount of daughter element produced by radioactive decay one can work out the age of the rock containing them assuming no loss or addition of both parent and daughter elements in the system. Objections that such an assumption is erroneous because the starting concentrations of these elements are unknown and hence no absolute dating is theoretically possible are countered by concordant ages obtained from different decay series from the same rock. For example, if the potassium-argon date is the same as the rubidium-strontium date then the argument that the potassium-argon date is unreliable because argon gas might have escaped from or diffused into the system is negated as strontium is a solid and unlikely to have diffused from the system in exactly the right proportion to give a concordant date as it is from a totally different independent decay series. On the other hand, discordant dates are common and expected because of the possibility of parent or daughter elements being added or lost from one or more of the decay series in the system. Other cross-checks can be done to determine whether contamination has occurred by for example, the presence of non-decay originated lead as opposed to decay produced lead in the uranium 238 - lead 206 series. Another cross-check is by fission tract dating of uranium 238 which is not based upon the amounts of parent and daughter products but on fission tracts produced by the high energy particles emitted penetrating the crystal lattice surrounding the uranium as it decayed.

Other less well known dating methods include dendrochronology or counting tree-rings, counting glacial varves, thermoluminescence, electron spin resonance, palaeomagnetism, fluorine dating and amino acid racemization. The age of the Universe has also been calculated based on the expansion rates of the different bodies in space to be between l3 to l5 billion years.

What about radiocarbon dating? Carbon 14 dating or radiocarbon dating is only useful for organic matter which are less than 70,000 years old as carbon 14 has only a short half-life of 5730 years and older samples would contain too little of it to be measured accurately. The dating works in this way. Carbon 14 is a rare isotope of carbon that forms in the upper atmosphere as a result of bombardment of nitrogen by cosmic rays. The newly formed carbon 14 together with the more abundant carbon 12 reacts with atmospheric oxygen to form carbon dioxide which is used for photosynthesis. Carbon 14 is thus incorporated into the food chain. Once an organism dies, no fresh carbon 14 is added to it and whatever carbon 14 that is trapped at that time begins to diminish with time as carbon 14 decays to nitrogen 14. Thus by comparing the relative abundance of carbon 14 in a piece of fossil wood, bone, leather or cloth with that in living matter it is possible to obtain age estimates of such objects. Because of its recent ages, carbon 14 dates have been successfully calibrated against tree-rings and archeological objects whose dates are known from historical records.

The main objections to an old age of the earth given by the young age creationists are focussed on the possible wrong assumptions and unreliability of the individual decay series. The argument is that since the starting concentrations of both the parent and daughter elements are unknown no absolute dating of the rock is possible. The dates could be wrong if material is lost or gained in the system especially if it involves a gas like argon. They have pointed out examples of discordant dates obtained by different methods from the same rocks or wrong dates from recently formed rocks such as the Island of Surtsey. They have said that mainstream scientists are biased and selectively accept only radiometric dates that fit in with the expected old dates and discard the young ones. They have pointed out that the rates of decay that is measured today could not be assumed to be unchanged and extrapolated back into billions of years. They have attempted to prove a young earth by mentioning that the amount of meteoric dust on the moon and salt in the seas are too little. Many of these have been countered with alternative reasonable explanations. For example, why there should be discordant dates in rocks and how there is actually a thick layer of compacted meteoric dust on the moon and salt is continuously removed from the seas by natural processes.

It seems that there are two opposing views to the age of the Earth, each with its own reasons and vested interests. The young-age creationists hope to prove scientifically that the Earth is young so that they can do away with evolution which requires long periods of time to take place. So far they have not been able to convince the mainstream scientific community of its claims as most of their “proofs” can be countered with alternative arguments. The long age of the Earth seems more likely based on the present understanding of the natural processes going on in the Earth. If that were so wouldn’t that contradict the Bible’s teaching that the Earth was created in six days?

Several attempts have been made to harmonize the old age of the Earth with the Genesis account of creation including:-
i) the day-age theory which interprets the days of Genesis as long periods of time instead of 24 hour days;ii) the days of revelation theory which says that the six days were the ones on which the writer of Genesis “saw” the different parts of creation revealed to him;

iii) the gap theory which says that there was a big gap of time between Genesis 1 : 1 and 1 : 2 where God recreated the Earth in a period of six 24 hours days after it became waste and empty in Genesis 1 : 1;

iv) appearance of age theory which postulates that God formed the earth several thousand years ago but gave it the appearance of being much older as He created the earth and its inhabitants in a mature, fully functional form (Adam and Eve were created as adults and not babies);

v) historical creationism which says that the word “beginning” in Genesis 1:1 refers to an indefinite time period when all the ancient geological events took place and the remaining days were only focussed on the preparation of a restricted piece of land called Eden for Adam and Eve;

vi) non-literal Genesis theory which says that the creation account is not to be take literally but it was written in a simple story form to convey to people of all time the central message that God created everything;

vii) My own theory that encoding time need not be equal to decoding time so that what may naturally require a long time to encode can be done supernaturally in six days (or six minutes or six seconds for that matter) but which we cannot discover using our present knowledge of science because it is beyond our understanding. We only know of it because we have been informed by divine revelation in Genesis. An analogy I have often used to illustrate this theory is that of high-speed taping. If I give you a cassette tape whose play-back or decoding time on your little tape-recorder is one hour, you would not believed me if I told you I produced (encoded) that tape in less than that time if you do not have any knowledge of the higher technology of high-speed taping .To you a tape that takes one hour to decode can only be encoded in one hour.

So how old is the Earth? I am not saying that it has to be 4.6 billion years old. That is the age which seems most likely based on our present limited understanding of science. We could be proved wrong tomorrow by new scientific discoveries. It could be as young as what the young-age creationists claim it to be as time is no problem to the Almighty God who is powerful enough to bring all things into existence by a divine miracle but the supernatural processes involved in creation would be beyond our understanding and comprehension (like turning water into wine!) at our present level of scientific knowledge. I can happily live with the divinely revealed information of a six-day creation and not worry too much about the billions of years as deduced by the present understanding of science knowing full-well that it cannot have the final word as we cannot travel back in time to find out how old really is the Earth.

By Assoc. Prof. Dr. Living Lee Chai Peng
Department of Geology, University of Malaya, 50603 Kuala Lumpur.
E-mail: leecp@um.edu.my
Contact number: 03-79674233