LDS author, Arvin Gibson, while a critic of macro-evolution (he advocates a form of Intelligent Design, similar to Behe et al), in light of the overwhelming evidence, admits that the earth (as well as the universe itself) is old, not young. In his 1999 book, Fingerprints of God, he wrote the following in Appendix B, “Basic Facts of the Universe”:
Age of the Earth
Prior to radiometric dating methods geologists attempted to determine time frames for different eras of the earth’s existence—which they designated as the Paleozoic, Mesozoic and Cenozoic (most recent) era—by relatively crude techniques. They estimated times of each of these eras based on different types and thicknesses of rock formations, rates of deposition, rates of erosion, development of life, and concentration of salt in the ocean. Although the techniques yielded time periods in the millions of years, they were subject to error and controversy. That all changed in 1913 when Arthur Holmes published a book entitled The Age of the Earth, which established the Phanerozoic Time Scale for the various geologic eras of the earth. This time scale included fourteen periods—compared with the three geologic periods used earlier—with the earliest period being the Cambrian (500-570 million years ago) (Considine, Douglas, Editor, Van Nostrand’s Scientific Encyclopedia, Fifth Edition, New York, London, Toronto, Melbourne: Van Nostrand Reinhold Company, 1976, p. 1157).
In his book Holmes outlined how age determinations based on principles of radioactive decay, in conjunction with geological data on the maximum known thicknesses of rocks assigned to the various geological periods, could be used to construct a quantitative time scale. The ratios of the daughter products, helium and lead, to the parent uranium, were used to calculate these early radioactivity ages.
Radioactive dating is based on the observed fact that radioactive materials decay at a fixed rate. Radiocarbon dating, for example, works because cosmic radiation entering our atmosphere transforms some of the nitrogen to radioactive carbon with a mass number of 14, represented as C14. The half life of C14 is 5,568 years, which means that in that period of time only one half of the original C14 will be left; the rest will have decayed into other elements. Over a period of time the carbon-14 in the atmosphere reacts with oxygen to form carbon dioxide, and it reaches a stable concentration in the atmosphere. Assuming that the observed stable concentration has always existed (a somewhat questionable assumption) the carbon dioxide ultimately gets absorbed in rocks, water and living things. Thus, if the bone of an ancient skeleton is only one half the concentration of the stable amount in the atmosphere, it may be concluded that the bone is 5,568 years old.
With the development of more sophisticated measuring instruments it has become possible to use other radioactive elements for more precise age determination. U238 decays to lead as its final stable element, but in the process it leaves behind eight helium atoms for each atom of uranium-238. Rocks which contain both elements, therefore, can have their age determined by ascertaining the ratio of uranium to helium. Several other decay chains of radioactive elements have also proved useful in accurately calculating age. An even more accurate method has been useful in calculating both fossil and rock ages. Volcanic ash frequently contains minuscule crystals known as zircons, and both radioactive uranium and lead are found in the crystals. By measuring the ratio of the parent uranium to its ultimate element, lead, precise ages can be established where zircon crystals are found. From radioactive dating of zircons found in Siberia scientists now generally agree that the start of the Cambrian period was 543 million years ago (Nash, J. Madeleine, “When Life Exploded,” Time, December 4, 1995, p. 70).
Returning now to the Phanerozoic time scale, it only proceeded as far back in time as the beginning of the Cambrian era. Using the uranium, helium and lead decay process coupled with spectrographic analysis scientists have been able to date rocks much further back into the pre-Cambrian era. These techniques have successfully established the age of the earth as 4.55 billion years (Considine, op. cit., p. 1158).
Age of the Universe
The age of the universe must, of course, be older than the age of the earth. Numerous indirect methods are used for dating the universe, but the most relied upon method is to use a reverse of the big bang model. I have already discussed the evidence for the big bang. That same evidence is valid for proceeding backward in time from the present to Planck time. Doing that yields a universe age from 10 to 20 billion years. The large span results from the uncertainty in various steps of the method. (Arvin S. Gibson, Fingerprints of God: Evidences for Near-Death Studies, Scientific Research on Creation, and Mormon Theology [Bountiful, Utah: Horizon Publishers and Distributors, Incorporated, 1999], 234-35, emphasis added)
