Christian perspective on radiometric dating
Each decays through a series of relatively short-lived radioactive elements that each decay to a lighter element, finally ending up at lead. Since these half-lives are so short compared to U, U, and thorium, they generally do not affect the overall dating scheme. The result is that one can obtain three independent estimates of the age of a rock by measuring the lead isotopes and their parent isotopes.
Long-term dating based on the U, U, and thorium will be discussed briefly here; dating based on some of the shorter-lived intermediate isotopes is discussed later. The uranium-lead system in its simpler forms, using U, U, and thorium, has proved to be less reliable than many of the other dating systems. This is because both uranium and lead are less easily retained in many of the minerals in which they are found.
Yet the fact that there are three dating systems all in one allows scientists to easily determine whether the system has been disturbed or not. Using slightly more complicated mathematics, different combinations of the lead isotopes and parent isotopes can be plotted in such a way as to. One of these techniques is called the lead-lead technique because it determines the ages from the lead isotopes alone. Some of these techniques allow scientists to chart at what points in time metamorphic heating events have occurred, which is also of significant interest to geologists.
The Age of the Earth. We now turn our attention to what the dating systems tell us about the age of the Earth. The most obvious constraint is the age of the oldest rocks. These have been dated at up to about four billion years. But actually only a very small portion of the Earth 's rocks are that old. From satellite data and other measurements we know that the Earth's surface is constantly rearranging itself little by little as Earth quakes occur. Such rearranging cannot occur without some of the Earth's surface disappearing under other parts of the Earth's surface, re-melting some of the rock.
So it appears that none of the rocks have survived from the creation of the Earth without undergoing remelting, metamorphism, or erosion, and all we can say--from this line of evidence--is that the Earth appears to be at least as old as the four billion year old rocks. When scientists began systematically dating meteorites they learned a very interesting thing: These meteorites are chips off the asteroids. When the asteroids were formed in space, they cooled relatively quickly some of them may never have gotten very warm , so all of their rocks were formed within a few million years.
The asteroids' rocks have not been remelted ever since, so the ages have generally not been disturbed. Meteorites that show evidence of being from the largest asteroids have slightly younger ages.
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The moon is larger than the largest asteroid. Most of the rocks we have from the moon do not exceed 4. The samples thought to be the oldest are highly pulverized and difficult to date, though there are a few dates extending all the way to 4. Most scientists think that all the bodies in the solar system were created at about the same time. Evidence from the uranium, thorium, and lead isotopes links the Earth's age with that of the meteorites.
This would make the Earth 4. There is another way to determine the age of the Earth. If we see an hourglass whose sand has run out, we know that it was turned over longer ago than the time interval it measures. Similarly, if we find that a radioactive parent was once abundant but has since run out, we know that it too was set longer ago than the time interval it measures.
There are in fact many, many more parent isotopes than those listed in Table 1. However, most of them are no longer found naturally on Earth--they have run out. Their half-lives range down to times shorter than we can measure. Every single element has radioisotopes that no longer exist on Earth! Many people are familiar with a chart of the elements Fig.
Nuclear chemists and geologists use a different kind of figure to show all of the isotopes. It is called a chart of the nuclides. Figure 7 shows a portion of this chart. It is basically a plot of the number of protons vs. Recall that an element is defined by how many protons it has. Each element can have a number of different isotopes, that is,. A portion of the chart of the nuclides showing isotopes of argon and potassium, and some of the isotopes of chlorine and calcium. Isotopes shown in dark green are found in rocks.
Isotopes shown in light green have short half-lives, and thus are no longer found in rocks. Short-lived isotopes can be made for nearly every element in the periodic table, but unless replenished by cosmic rays or other radioactive isotopes, they no longer exist in nature. So each element occupies a single row, while different isotopes of that element lie in different columns.
For potassium found in nature, the total neutrons plus protons can add up to 39, 40, or Potassium and are stable, but potassium is unstable, giving us the dating methods discussed above. Besides the stable potassium isotopes and potassium, it is possible to produce a number of other potassium isotopes, but, as shown by the half-lives of these isotopes off to the side, they decay away. Now, if we look at which radioisotopes still exist and which do not, we find a very interesting fact. Nearly all isotopes with half-lives shorter than half a billion years are no longer in existence.
For example, although most rocks contain significant amounts of Calcium, the isotope Calcium half-life , years does not exist just as potassium, , , etc. Just about the only radioisotopes found naturally are those with very long half-lives of close to a billion years or longer, as illustrated in the time line in Fig. The only isotopes present with shorter half-lives are those that have a source constantly replenishing them. Chlorine shown in Fig.
In a number of cases there is. Some of these isotopes and their half-lives are given in Table II. This is conclusive evidence that the solar system was created longer ago than the span of these half lives! On the other hand, the existence in nature of parent isotopes with half lives around a billion years and longer is strong evidence that the Earth was created not longer ago than several billion years.
Where does the evidence lead?
The Earth is old enough that radioactive isotopes with half-lives less than half a billion years decayed away, but not so old that radioactive isotopes with longer half-lives are gone. This is just like finding hourglasses measuring a long time interval still going, while hourglasses measuring shorter intervals have run out. Years Plutonium 82 million Iodine 16 million Palladium 6.
Unlike the radioactive isotopes discussed above, these isotopes are constantly being replenished in small amounts in one of two ways. The bottom two entries, uranium and thorium, are replenished as the long-lived uranium atoms decay. These will be discussed in the next section. The other three, Carbon, beryllium, and chlorine are produced by cosmic rays--high energy particles and photons in space--as they hit the Earth's upper atmosphere. Very small amounts of each of these isotopes are present in the air we breathe and the water we drink.
As a result, living things, both plants and animals, ingest very small amounts of carbon, and lake and sea sediments take up small amounts of beryllium and chlorine The cosmogenic dating clocks work somewhat differently than the others. Carbon in particular is used to date material such as bones, wood, cloth, paper, and other dead tissue from either plants or animals. To a rough approximation, the ratio of carbon to the stable isotopes, carbon and carbon, is relatively constant in the atmosphere and living organisms, and has been well calibrated.
Once a living thing dies, it no longer takes in carbon from food or air, and the amount of carbon starts to drop with time. Since the half-life of carbon is less than 6, years, it can only be used for dating material less than about 45, years old. Dinosaur bones do not have carbon unless contaminated , as the dinosaurs became extinct over 60 million years ago. But some other animals that are now extinct, such as North American mammoths, can be dated by carbon Also, some materials from prehistoric times, as well as Biblical events, can be dated by carbon The carbon dates have been carefully cross-checked with non-radiometric age indicators.
For example growth rings in trees, if counted carefully, are a reliable way to determine the age of a tree. Each growth ring only collects carbon from the air and nutrients during the year it is made. To calibrate carbon, one can analyze carbon from the center several rings of a tree, and then count the rings inward from the living portion to determine the actual age. This has been done for the "Methuselah of trees", the bristlecone pine trees, which grow very slowly and live up to 6, years. Scientists have extended this calibration even further. These trees grow in a very dry region near the California-Nevada border.
Dead trees in this dry climate take many thousands of years to decay. Growth ring patterns based on wet and dry years can be correlated between living and long dead trees, extending the continuous ring count back to 11, years ago. An effort is presently underway to bridge the gaps so as to have a reliable, continuous record significantly farther back in time. The study of tree rings and the ages they give is called "dendrochronology". Calibration of carbon back to almost 50, years ago has been done in several ways.
One way is to find yearly layers that are produced over longer periods of time than tree rings. In some lakes or bays where underwater sedimentation occurs at a relatively rapid rate, the sediments have seasonal patterns, so each year produces a distinct layer. Such sediment layers are called "varves", and are described in more detail below. Varve layers can be counted just like tree rings.
If layers contain dead plant material, they can be used to calibrate the carbon ages. Another way to calibrate carbon farther back in time is to find recently-formed carbonate deposits and cross-calibrate the carbon in them with another short-lived radioactive isotope. Where do we find recently-formed carbonate deposits? If you have ever taken a tour of a cave and seen water dripping from stalactites on the ceiling to stalagmites on the floor of the cave, you have seen carbonate deposits being formed.
Since most cave formations have formed relatively recently, formations such as stalactites and stalagmites have been quite useful in cross-calibrating the carbon record. What does one find in the calibration of carbon against actual ages? If one predicts a carbon age assuming that the ratio of carbon to carbon in the air has stayed constant, there is a slight error because this ratio has changed slightly.
Figure 9 shows that the carbon fraction in the air has decreased over the last 40, years by about a factor of two. This is attributed to a strengthening of the Earth's magnetic field during this time. A stronger magnetic field shields the upper atmosphere better from charged cosmic rays, resulting in less carbon production now than in the past. Changes in the Earth's magnetic field are well documented. Complete reversals of the north and south magnetic poles have occurred many times over geologic history.
A small amount of data beyond 40, years not shown in Fig. What change does this have on uncalibrated carbon ages? The bottom panel of Figure 9 shows the amount. Ratio of atmospheric carbon to carbon, relative to the present-day value top panel. Tree-ring data are from Stuiver et al. The offset is generally less than years over the last 10, years, but grows to about 6, years at 40, years before present.
Uncalibrated radiocarbon ages underestimate the actual ages. Note that a factor of two difference in the atmospheric carbon ratio, as shown in the top panel of Figure 9, does not translate to a factor of two offset in the age. Rather, the offset is equal to one half-life, or 5, years for carbon The initial portion of the calibration curve in Figure 9 has been widely available and well accepted for some time, so reported radiocarbon dates for ages up to 11, years generally give the calibrated ages unless otherwise stated. The calibration curve over the portions extending to 40, years is relatively recent, but should become widely adopted as well.
It is sometimes possible to date geologically young samples using some of the long-lived methods described above. These methods may work on young samples, for example, if there is a relatively high concentration of the parent isotope in the sample. In that case, sufficient daughter isotope amounts are produced in a relatively short time. As an example, an article in Science magazine vol.
There are other ways to date some geologically young samples. Besides the cosmogenic radionuclides discussed above, there is one other class of short-lived radionuclides on Earth. These are ones produced by decay of the long-lived radionuclides given in the upper part of Table 1. As mentioned in the Uranium-Lead section, uranium does not decay immediately to a stable isotope, but decays through a number of shorter-lived radioisotopes until it ends up as lead.
While the uranium-lead system can measure intervals in the millions of years generally without problems from the intermediate isotopes, those intermediate isotopes with the longest half-lives span long enough time intervals for dating events less than several hundred thousand years ago. Note that these intervals are well under a tenth of a percent of the half-lives of the long-lived parent uranium and thorium isotopes discussed earlier. Two of the most frequently-used of these "uranium-series" systems are uranium and thorium These are listed as the last two entries in Table 1, and are illustrated in Figure A schematic representation of the uranium decay chain, showing the longest-lived nuclides.
Half-lives are given in each box. Solid arrows represent direct decay, while dashed arrows indicate that there are one or more intermediate decays, with the longest intervening half-life given below the arrow. Like carbon, the shorter-lived uranium-series isotopes are constantly being replenished, in this case, by decaying uranium supplied to the Earth during its original creation.
Following the example of carbon, you may guess that one way to use these isotopes for dating is to remove them from their source of replenishment. This starts the dating clock. In carbon this happens when a living thing like a tree dies and no longer takes in carbonladen CO 2. For the shorter-lived uranium-series radionuclides, there needs to be a physical removal from uranium. The chemistry of uranium and thorium are such that they are in fact easily removed from each other.
Uranium tends to stay dissolved in water, but thorium is insoluble in water. So a number of applications of the thorium method are based on this chemical partition between uranium and thorium. Sediments at the bottom of the ocean have very little uranium relative to the thorium. Because of this, the uranium, and its contribution to the thorium abundance, can in many cases be ignored in sediments. Thorium then behaves similarly to the long-lived parent isotopes we discussed earlier. It acts like a simple parent-daughter system, and it can be used to date sediments.
On the other hand, calcium carbonates produced biologically such as in corals, shells, teeth, and bones take in small amounts of uranium, but essentially no thorium because of its much lower concentrations in the water. This allows the dating of these materials by their lack of thorium. A brand-new coral reef will have essentially no thorium As it ages, some of its uranium decays to thorium While the thorium itself is radioactive, this can be corrected for.
Comparison of uranium ages with ages obtained by counting annual growth bands of corals proves that the technique is. The method has also been used to date stalactites and stalagmites from caves, already mentioned in connection with long-term calibration of the radiocarbon method. In fact, tens of thousands of uranium-series dates have been performed on cave formations around the world. Previously, dating of anthropology sites had to rely on dating of geologic layers above and below the artifacts.
But with improvements in this method, it is becoming possible to date the human and animal remains themselves. Work to date shows that dating of tooth enamel can be quite reliable. However, dating of bones can be more problematic, as bones are more susceptible to contamination by the surrounding soils. As with all dating, the agreement of two or more methods is highly recommended for confirmation of a measurement. If the samples are beyond the range of radiocarbon e. We will digress briefly from radiometric dating to talk about other dating techniques.
It is important to understand that a very large number of accurate dates covering the past , years has been obtained from many other methods besides radiometric dating. We have already mentioned dendrochronology tree ring dating above. Dendrochronology is only the tip of the iceberg in terms of non-radiometric dating methods. Here we will look briefly at some other non-radiometric dating techniques.
One of the best ways to measure farther back in time than tree rings is by using the seasonal variations in polar ice from Greenland and Antarctica. There are a number of differences between snow layers made in winter and those made in spring, summer, and fall. These seasonal layers can be counted just like tree rings. The seasonal differences consist of a visual differences caused by increased bubbles and larger crystal size from summer ice compared to winter ice, b dust layers deposited each summer, c nitric acid concentrations, measured by electrical conductivity of the ice, d chemistry of contaminants in the ice, and e seasonal variations in the relative amounts of heavy hydrogen deuterium and heavy oxygen oxygen in the ice.
These isotope ratios are sensitive to the temperature at the time they fell as snow from the clouds. The heavy isotope is lower in abundance during the colder winter snows than it is in snow falling in spring and summer. So the yearly layers of ice can be tracked by each of these five different indicators, similar to growth rings on trees. The different types of layers are summarized in Table III. Ice cores are obtained by drilling very deep holes in the ice caps on Greenland and Antarctica with specialized drilling rigs. As the rigs drill down, the drill bits cut around a portion of the ice, capturing a long undisturbed "core" in the process.
These cores are carefully brought back to the surface in sections, where they are catalogued, and taken to research laboratories under refrigeration. A very large amount of work has been done on several deep ice cores up to 9, feet in depth. Several hundred thousand measurements are sometimes made for a single technique on a single ice core. A continuous count of layers exists back as far as , years. In addition to yearly layering, individual strong events such as large-scale volcanic eruptions can be observed and correlated between ice cores.
A number of historical eruptions as far back as Vesuvius nearly 2, years ago serve as benchmarks with which to determine the accuracy of the yearly layers as far down as around meters.
Radiometric dating from a “Christian perspective”
As one goes further down in the ice core, the ice becomes more compacted than near the surface, and individual yearly layers are slightly more difficult to observe. For this reason, there is some uncertainty as one goes back towards , years. Recently, absolute ages have been determined to 75, years for at least one location using cosmogenic radionuclides chlorine and beryllium G.
These agree with the ice flow models and the yearly layer counts. Note that there is no indication anywhere that these ice caps were ever covered by a large body of water, as some people with young-Earth views would expect. Polar ice core layers, counting back yearly layers, consist of the following:. Visual Layers Summer ice has more bubbles and larger crystal sizes Observed to 60, years ago Dust Layers Measured by laser light scattering; most dust is deposited during spring and summer Observed to , years ago Layering of Elec-trical Conductivity Nitric acid from the stratosphere is deposited in the springtime, and causes a yearly layer in electrical conductivity measurement Observed through 60, years ago Contaminant Chemistry Layers Soot from summer forest fires, chemistry of dust, occasional volcanic ash Observed through 2, years; some older eruptions noted Hydrogen and Oxygen Isotope Layering Indicates temperature of precipitation.
Heavy isotopes oxygen and deuterium are depleted more in winter. Yearly layers observed through 1, years; Trends observed much farther back in time Varves. Another layering technique uses seasonal variations in sedimentary layers deposited underwater. The two requirements for varves to be useful in dating are 1 that sediments vary in character through the seasons to produce a visible yearly pattern, and 2 that the lake bottom not be disturbed after the layers are deposited. These conditions are most often met in small, relatively deep lakes at mid to high latitudes.
Shallower lakes typically experience an overturn in which the warmer water sinks to the bottom as winter approaches, but deeper lakes can have persistently thermally stratified temperature-layered water masses, leading to less turbulence, and better conditions for varve layers. Varves can be harvested by coring drills, somewhat similar to the harvesting of ice cores discussed above. Overall, many hundreds of lakes have been studied for their varve patterns. Each yearly varve layer consists of a mineral matter brought in by swollen streams in the spring.
Regular sequences of varves have been measured going back to about 35, years.
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- Earth Science Guy: Radiometric Dating: A Christian Perspective.
The thicknesses of the layers and the types of material in them tells a lot about the climate of the time when the layers were deposited. For example, pollens entrained in the layers can tell what types of plants were growing nearby at a particular time. Other annual layering methods. Besides tree rings, ice cores, and sediment varves, there are other processes that result in yearly layers that can be counted to determine an age. Annual layering in coral reefs can be used to date sections of coral. Coral generally grows at rates of around 1 cm per year, and these layers are easily visible.
As was mentioned in the uranium-series section, the counting of annual coral layers was used to verify the accuracy of the thorium method. There is a way of dating minerals and pottery that does not rely directly on half-lives. Thermoluminescence dating, or TL dating, uses the fact that radioactive decays cause some electrons in a material to end up stuck in higher-energy orbits. The number of electrons in higher-energy orbits accumulates as a material experiences more natural radioactivity over time. If the material is heated, these electrons can fall back to their original orbits, emitting a very tiny amount of light.
If the heating occurs in a laboratory furnace equipped with a very sensitive light detector, this light can be recorded. The term comes from putting together thermo , meaning heat, and luminescence , meaning to emit light. By comparison of the amount of light emitted with the natural radioactivity rate the sample experienced, the age of the sample can be determined.
TL dating can generally be used on samples less than half a million years old. TL dating and its related techniques have been cross calibrated with samples of known historical age and with radiocarbon and thorium dating. While TL dating does not usually pinpoint the age with as great an accuracy as these other conventional radiometric dating, it is most useful for applications such as pottery or fine-grained volcanic dust, where other dating methods do not work as well.
Electron spin resonance ESR. Also called electron paramagnetic resonance, ESR dating also relies on the changes in electron orbits and spins caused by radioactivity over time. However, ESR dating can be used over longer time periods, up to two million years, and works best on carbonates, such as in coral reefs and cave deposits. It has also seen extensive use in dating tooth enamel. This dating method relies on measuring certain isotopes produced by cosmic ray impacts on exposed rock surfaces.
Because cosmic rays constantly bombard meteorites flying through space, this method has long been used to date the ' flight time' of meteorites--that is the time from when they were chipped off a larger body like an asteroid to the time they land on Earth. The cosmic rays produce small amounts of naturally-rare isotopes such as neon and helium-3, which can be measured in the laboratory.
The cosmic-ray exposure ages of meteorites are usually around 10 million years, but can be up to a billion years for some iron meteorites. In the last fifteen years, people have also used cosmic ray exposure ages to date rock surfaces on the Earth. This is much more complicated because the Earth's magnetic field and atmosphere shield us from most of the cosmic rays. Cosmic ray exposure calibrations must take into. Nevertheless, terrestrial cosmic-ray exposure dating has been shown to be useful in many cases.
We have covered a lot of convincing evidence that the Earth was created a very long time ago. The agreement of many different dating methods, both radiometric and non-radiometric, over hundreds of thousands of samples, is very convincing. Yet, some Christians question whether we can believe something so far back in the past.
My answer is that it is similar to believing in other things of the past. It only differs in degree. Why do you believe Abraham Lincoln ever lived? Because it would take an extremely elaborate scheme to make up his existence, including forgeries, fake photos, and many other things, and besides, there is no good reason to simply have made him up. Well, the situation is very similar for the dating of rocks, only we have rock records rather than historical records.
The last three points deserve more attention. Some Christians have argued that something may be slowly changing with time so all the ages look older than they really are. The only two quantities in the exponent of a decay rate equation are the half-life and the time. So for ages to appear longer than actual, all the half-lives would have to be changing in sync with each other. One could consider that time itself was changing if that happened remember that our clocks are now standardized to atomic clocks!
Beyond this, scientists have now used a "time machine" to prove that the half-lives of radioactive species were the same millions of years ago. This time machine does not allow people to actually go back in time, but it does allow scientists to observe ancient events from a long way away. The time machine is called the telescope. Because God's universe is so large, images from distant events take a long time to get to us. Telescopes allow us to see supernovae exploding stars at distances so vast that the pictures take hundreds of thousands to millions of years to arrive at the Earth.
So the events we see today actually occurred hundreds of thousands to millions of years ago. And what do we see when we look back in time? Much of the light following a supernova blast is powered by newly created radioactive parents. So we observe radiometric decay in the supernova light. The half-lives of decays occurring hundreds of thousands of years ago are thus carefully recorded! These half-lives completely agree with the half-lives measured from decays occurring today. We must conclude that all evidence points towards unchanging radioactive half-lives.
Some individuals have suggested that the speed of light must have been different in the past, and that the starlight has not really taken so long to reach us. However, the astronomical evidence mentioned above also suggests that the speed of light has not changed, or else we would see a significant apparent change in the half-lives of these ancient radioactive decays.
Some doubters have tried to dismiss geologic dating with a sleight of hand by saying that no rocks are completely closed systems that is, that no rocks are so isolated from their surroundings that they have not lost or gained some of the isotopes used for dating. Speaking from an extreme technical viewpoint this might be true--perhaps 1 atom out of 1,,,, of a certain isotope has leaked out of nearly all rocks, but such a change would make an immeasurably small change in the result.
The real question to ask is, "is the rock sufficiently close to a closed system that the results will be same as a really closed system? These books detail experiments showing, for a given dating system, which minerals work all of the time, which minerals work under some certain conditions, and which minerals are likely to lose atoms and give incorrect results. Understanding these conditions is part of the science of geology. Geologists are careful to use the most reliable methods whenever possible, and as discussed above, to test for agreement between different methods.
Some people have tried to defend a young Earth position by saying that the half-lives of radionuclides can in fact be changed, and that this can be done by certain little-understood particles such as neutrinos, muons, or cosmic rays. This is stretching it. While certain particles can cause nuclear changes, they do not change the half-lives. The nuclear changes are well understood and are nearly always very minor in rocks. In fact the main nuclear changes in rocks are the very radioactive decays we are talking about.
There are only three quite technical instances where a half-life changes, and these do not affect the dating methods we have discussed. Only one technical exception occurs under terrestrial conditions, and this is not for an isotope used for dating. According to theory, electron-capture is the most likely type of decay to show changes with pressure or chemical combination, and this should be most pronounced for very light elements.
The artificially-produced isotope, beryllium-7 has been shown to change by up to 1. In another experiment, a half-life change of a small fraction of a percent was detected when beryllium-7 was subjected to , atmospheres of pressure, equivalent to depths greater than miles inside the Earth Science , , All known rocks, with the possible exception of diamonds, are from much shallower depths. In fact, beryllium-7 is not used for dating rocks, as it has a half-life of only 54 days, and heavier atoms are even less subject to these minute changes, so the dates of rocks made by electron-capture decays would only be off by at most a few hundredths of a percent.
Physical conditions at the center of stars or for cosmic rays differ very greatly from anything experienced in rocks on or in the Earth. Yet, self-proclaimed "experts" often confuse these conditions. Cosmic rays are very, very high-energy atomic nuclei flying through space. The electron-capture decay mentioned above does not take place in cosmic rays until they slow down. This is because the fast-moving cosmic ray nuclei do not have electrons surrounding them, which are necessary for this form of decay.
Another case is material inside of stars, which is in a plasma state where electrons are not bound to atoms. In the extremely hot stellar environment, a completely different kind of decay can occur. This has been observed for dysprosium and rhenium under very specialized conditions simulating the interior of stars Phys.
All normal matter, such as everything on Earth, the Moon, meteorites, etc. As an example of incorrect application of these conditions to dating, one young-Earth proponent suggested that God used plasma conditions when He created the Earth a few thousand years ago. This writer suggested that the rapid decay rate of rhenium under extreme plasma conditions might explain why rocks give very old ages instead of a young-Earth age.
This writer neglected a number of things, including: More importantly, b rocks and hot gaseous plasmas are completely incompatible forms of matter! The material would have to revert back from the plasma state before it could form rocks. In such a scenario, as the rocks cooled and hardened, their ages would be completely reset to zero as described in previous sections. That is obviously not what is observed. The last case also involves very fast-moving matter.
It has been demonstrated by atomic clocks in very fast spacecraft. These atomic clocks slow down very slightly only a second or so per year as predicted by Einstein's theory of relativity. No rocks in our solar system are going fast enough to make a noticeable change in their dates. These cases are very specialized, and all are well understood. None of these cases alter the dates of rocks either on Earth or other planets in the solar system. The conclusion once again is that half-lives are completely reliable in every context for the dating of rocks on Earth and even on other planets.
The Earth and all creation appears to be very ancient. It would not be inconsistent with the scientific evidence to conclude that God made everything relatively recently, but with the appearance of great age, just as Genesis 1 and 2 tell of God making Adam as a fully grown human which implies the appearance of age. This idea was captured by Phillip Henry Gosse in the book, " Omphalos: The idea of a false appearance of great age is a philosophical and theological matter that we won't go into here.
The main drawback--and it is a strong one--is that this makes God appear to be a deceiver. Certainly whole civilizations have been incorrect deceived? Whatever the philosophical conclusions, it is important to note that an apparent old Earth is consistent with the great amount of scientific evidence. As Christians it is of great importance that we understand God's word correctly. Yet from the middle ages up until the s people insisted that the Bible taught that the Earth, not the Sun, was the center of the solar system. It wasn't that people just thought it had to be that way; they actually quoted scriptures: I am afraid the debate over the age of the Earth has many similarities.
But I am optimistic. Today there are many Christians who accept the reliability of geologic dating, but do not compromise the spiritual and historical inerrancy of God's word. While a full discussion of Genesis 1 is not given here, references are given below to a few books that deal with that issue. There are a number of misconceptions that seem especially prevalent among Christians.
Most of these topics are covered in the above discussion, but they are reviewed briefly here for clarity. Radiometric dating is based on index fossils whose dates were assigned long before radioactivity was discovered. This is not at all true, though it is implied by some young-Earth literature. Radiometric dating is based on the half-lives of the radioactive isotopes. These half-lives have been measured over the last years. They are not calibrated by fossils. No one has measured the decay rates directly; we only know them from inference. Decay rates have been directly measured over the last years.
In some cases a batch of the pure parent material is weighed and then set aside for a long time and then the resulting daughter material is weighed. In many cases it is easier to detect radioactive decays by the energy burst that each decay gives off. For this a batch of the pure parent material is carefully weighed and then put in front of a Geiger counter or gamma-ray detector.
These instruments count the number of decays over a long time. If the half-lives are billions of years, it is impossible to determine them from measuring over just a few years or decades. The example given in the section titled, "The Radiometric Clocks" shows that an accurate determination of the half-life is easily achieved by direct counting of decays over a decade or shorter. This is because a all decay curves have exactly the same shape Fig.
Additionally, lavas of historically known ages have been correctly dated even using methods with long half-lives. Most of the decay rates used for dating rocks are known to within two percent. Such small uncertainties are no reason to dismiss radiometric dating. Whether a rock is million years or million years old does not make a great deal of difference. A small error in the half-lives leads to a very large error in the date. Since exponents are used in the dating equations, it is possible for people to think this might be true, but it is not.
This is not true in the context of dating rocks. Radioactive atoms used for dating have been subjected to extremes of heat, cold, pressure, vacuum, acceleration, and strong chemical reactions far beyond anything experienced by rocks, without any significant change. The only exceptions, which are not relevant to dating rocks, are discussed under the section, "Doubters Still Try", above. A small change in the nuclear forces probably accelerated nuclear clocks during the first day of creation a few thousand years ago, causing the spuriously old radiometric dates of rocks.
Rocks are dated from the time of their formation. For it to have any bearing on the radiometric dates of rocks, such a change of nuclear forces must have occurred after the Earth and the rocks were formed. To make the kind of difference suggested by young-Earth proponents, the half-lives must be shortened from several billion years down to several thousand years--a factor of at least a million. But to shorten half-lives by factors of a million would cause large physical changes.
As one small example, recall that the Earth is heated substantially by radioactive decay. If that decay is speeded up by a factor of a million or so, the tremendous heat pulse would easily melt the whole Earth , including the rocks in question! No radiometric ages would appear old if this happened. The decay rates might be slowing down over time, leading to incorrect old dates. There are two ways we know this didn't happen: We should measure the "full-life" the time at which all of the parent is gone rather than the half-life the time when half of it is gone.
Unlike sand in an hourglass, which drops at a constant rate independent of how much remains in the top half of the glass, the number of radioactive decays is proportional to the amount of parent remaining. A half-life is more easy to define than some point at which almost all of the parent is gone. Scientists sometimes instead use the term "mean life", that is, the average life of a parent atom. For most of us half-life is easier to understand.
To date a rock one must know the original amount of the parent element. But there is no way to measure how much parent element was originally there. It is very easy to calculate the original parent abundance, but that information is not needed to date the rock. All of the dating schemes work from knowing the present abundances of the parent and daughter isotopes. There is little or no way to tell how much of the decay product, that is, the daughter isotope, was originally in the rock, leading to anomalously old ages.
A good part of this article is devoted to explaining how one can tell how much of a given element or isotope was originally present. Usually it involves using more than one sample from a given rock. It is done by comparing the ratios of parent and daughter isotopes relative to a stable isotope for samples with different relative amounts of the parent isotope.
From this one can determine how much of the daughter isotope would be present if there had been no parent isotope. This is the same as the initial amount it would not change if there were no parent isotope to decay. Figures 4 and 5, and the accompanying explanation, tell how this is done most of the time. This article has listed and discussed a number of different radiometric dating methods and has also briefly described a number of non-radiometric dating methods. There are actually many more methods out there. Well over forty different radiometric dating methods are in use, and a number of non-radiogenic methods not even mentioned here.
This refers to tiny halos of crystal damage surrounding spots where radioactive elements are concentrated in certain rocks. Halos thought to be from polonium, a short-lived element produced from the decay of uranium, have been found in some rocks. A plausible explanation for a halo from such a short-lived element is that these were not produced by an initial concentration of the radioactive element.
Rather, as water seeped through cracks in the minerals, a chemical change caused newly-formed polonium to drop out of solution at a certain place and almost immediately decay there. A halo would build up over a long period of time even though the center of the halo never contained more than a few atoms of polonium at one time.
Other researchers have found halos produced by an indirect radioactive decay effect called hole diffusion, which is an electrical effect in a crystal. These results suggest that the halos in question are not from short-lived isotopes after all. At any rate, halos from uranium inclusions are far more common.
Because of uranium's long half-lives, these halos take at least several hundred million years to form. Because of this, most people agree that halos provide compelling evidence for a very old Earth. A young-Earth research group reported that they sent a rock erupted in from Mount Saint Helens volcano to a dating lab and got back a potassium-argon age of several million years. This shows we should not trust radiometric dating. There are indeed ways to "trick" radiometric dating if a single dating method is improperly used on a sample. Anyone can move the hands on a clock and get the wrong time.
Likewise, people actively looking for incorrect radiometric dates can in fact get them. Geologists have known for over forty years that the potassium-argon method cannot be used on rocks only twenty to thirty years old. Publicizing this incorrect age as a completely new finding was inappropriate. The reasons are discussed in the Potassium-Argon Dating section above. Be assured that multiple dating methods used together on igneous rocks are almost always correct unless the sample is too difficult to date due to factors such as metamorphism or a large fraction of xenoliths.
Low abundances of helium in zircon grains show that these minerals are much younger than radiometric dating suggests. Zircon grains are important for uranium-thorium-lead dating because they contain abundant uranium and thorium parent isotopes. Helium is also produced from the decay of uranium and thorium. However, as a gas of very small atomic size, helium tends to escape rather easily. Researchers have studied the rates of diffusion of helium from zircons, with the prediction from one study by a young- Earth creationist suggesting that it should be quantitatively retained despite its atomic size.
The assumptions of the temperature conditions of the rock over time are most likely unrealistic in this case. The fact that radiogenic helium and argon are still degassing from the Earth's interior prove that the Earth must be young. The radioactive parent isotopes, uranium and potassium, have very long half-lives, as shown in Table 1. These parents still exist in abundance in the Earth's interior, and are still producing helium and argon. There is also a time lag between the production of the daughter products and their degassing. If the Earth were geologically very young, very little helium and argon would have been produced.
One can compare the amount of argon in the atmosphere to what would be expected from decay of potassium over 4. The waters of Noah's flood could have leached radioactive isotopes out of rocks, disturbing their ages. This is actually suggested on one website! While water can affect the ability to date rock surfaces or other weathered areas, there is generally no trouble dating interior portions of most rocks from the bottom of lakes, rivers, and oceans.
Additionally, if ages were disturbed by leaching, the leaching would affect different isotopes at vastly different rates. Ages determined by different methods would be in violent disagreement. If the flood were global in scope, why then would we have any rocks for which a number of different methods all agree with each other? In fact, close agreement between methods for most samples is a hallmark of radiometric dating.
We know the Earth is much younger because of non-radiogenic indicators such as the sedimentation rate of the oceans. There are a number of parameters which, if extrapolated from the present without taking into account the changes in the Earth over time, would seem to suggest a somewhat younger Earth. These arguments can sound good on a very simple level, but do not hold water when all the factors are considered. Some examples of these categories are the decaying magnetic field not mentioning the widespread evidence for magnetic reversals , the saltiness of the oceans not counting sedimentation!
While these arguments do not stand up when the complete picture is considered, the case for a very old creation of the Earth fits well in all areas considered. I first became aware of the holes in the naturalistic explanations of the universe in when I began to ask questions about star formation. These questions are still unanswered. There is no workable theory for the formation of the first stars. Consider these statements about this:. Fifty cosmologists attended a conference on galaxy formation.
After summarizing much observational data, two of the most respected authorities optimistically estimated the probability that any existing theory on galaxy formation is correct is about 1 out of Why is this such a problem? Simple — hot expanding gas does not gravitationally collapse — physics gets in the way.
Here is a short description of the problem: Please share any you know of. You used it to denote that it meant research by Christians who hold a Young Earth view. Not trying to offend. Of course God is outside of creation and he can intervene in any way he sees fit. Do you mean by materialistic that all of the universe must be self caused? In my opinion, the big bang theory has forced scientists to grapple with the idea of a beginning, and thus a Beginner, and this has been a good thing. However, this is a spiritual and heart issue, not a scientific one.
This does not mean that nobody in the scientific community cannot recognize the truth. We should expect scientists to see God through their scientific work. Especially when the Bible tells us that all of creation testifies about God. The three statements you quoted from Binney, Silk, and Abraham Loeb were interesting as well. Much has changed in the scientific community knowledge-wise since I was unable to view the quotes in their original contexts but I searched Abraham Loeb and found his Harvard page. Here is a link to the book. To respond to the quote you posted by Dr.
Humphreys word that he had no good answers, whatever his definition of good answer means. Also, why would Dr. Weins among the hundreds of geoscientists who came by? It seems the only purpose of this sentence is to claim that hundreds of geoscientists checked out their posters. Humphreys and Danny Faulkner also presented. I would be interested in Dr. Weins opinion on the RATE research as well. To use a private conversation to attack someone you disagree with is not very good form. Humphreys that it would be interesting to hear Dr. Weins opinion on the RATE research.
Weins is afraid of the RATE research. I need to go, so I will answer your question of what evidence would make me doubt an old age of the earth in a following post. It is a good question and deserves a fair response. Thanks for dialoguing with me. Ok, I have a chance to write my thoughts down in regards to your question about what evidences would make me doubt an old earth view. There are several that I would pose. First, I have yet to see a convincing argument for Adam naming all the animals in one hour day that accounts for the importance of names. Names are not given lightly throughout scripture.
Names denote character, and symbolize a change in covenant with both Abraham and Jacob. Why should the naming of the animals, a task given specifically by God to Adam, be any different? To treat the naming of the animals lightly, as it must be if Adam is to name every animal in only a few hours, spending only seconds to do so, is very flippant and not in sync with what I see in the rest of scripture. Secondly, I would like to see evidence that a global flood could produce all the geographical formations we see throughout the earth.
Sure, floods can, and do, produce certain geological formations. There have been scores of articles and books written on this subject, and I have read some of them. However, the vast majority of geology can be easily explained with modern geological theory, emphasis on easily. The same geology is much more difficult to explain by a catastrophic flood. Keep in mind that most geologists that founded the science were Christians. Third, I would like to see a good explanation why ice cores are invalid in counting a date older than years. There has been much that has been recently written about ice cores, I assume because of the debate between Ken Ham and Bill Nye.
All I have seen up to this point is the arguments that scientists are not accounting for the compression of the ice, that scientists assume ice conditions have always been the same laughable , and that so much error has been introduced into their calculations that they are mistakenly led to believe that it is way older than years. These are poor arguments and not convincing.
Forth, I would like to hear a good explanation of how the animals re-populated the earth after the Global Flood. The diversity of life throughout the earth, is simply too much to account for if they all originated from one location, i. The sheer diversity of creatures in the Amazon alone is enough for me to question a global flood. Finally, I would like to hear an good response to this. To view God as a careful craftsman, lovingly preparing the world over so long, gives me a much greater appreciation and makes me worship Him more deeply. Could God create the world in six hour days?
Please take another look at the ASA page. It is one page because it is an outline describing the RATE research and the responses to it, as well as counter-responses by both sides. Links are provided to all the different papers and articles so that one may examine what each side is saying and come to your own conclusion. Let me summarize my sentence by sentence reposne that I posted earlier to Dr. I am also curious about Dr. Weins opinions on the RATE research. That does not mean he has an obligation to respond, especially when he has colleagues who have responded to RATE in writing.
I could infer that he has similar views as to his colleagues, and that there is no need for him to respond personally as he has not written anything personally. Also, it seems to me that he has been extremely busy with his current project on Mars, and perhaps he simply has not had the time. My criticism of Dr.
This is why writing is powerful. For example, I could claim that I met Dr. Humphreys at his conference booth and asked him questions about his posters on the RATE research. I could then write a review on some blog saying that I had a conversation with Dr. In fact, he said to me that it would be presumptious of him to challenge the plain reading of scripture for him to consider any other interpretations of radiometric dating.
It is just as inappropriate for me to say this, especially if I was criticizing Dr. Just to be clear, I have not met or spoken with Dr. Humphreys personally and this was a made up example. There is so much research out there in an attempt to create a workable theory, of which there are several theories with varying degrees of plausibility, but it seems that you would reject most of it. I can make assumptions as to why you seem to reject most of it, but that would be putting word into your mouth.
Would research by Evangelical Christians be acceptable, since they approach research with God in mind, even if they assert an old earth viewpoint?
Radiometric dating from a “Christian perspective” | Creation – Myth or Miracle?
I applaud them for challenging the aspects in radiometric dating they felt were untenable because the truth is what matters. But I judge their research the same as I judge any other. One must examine the methodology, the assumptions, the adjustments and calculations for sources of error, in any research project.