Radiometric dating is done by comparing the ratio of

Radiometric Dating: A Christian Perspective. Roger C. Wiens has a PhD in Physics, with a minor in Geology. His PhD thesis was on isotope ratios in meteorites, including surface exposure dating. First edition ; revised version

Radiometric dating

Radiometric Dating: A Christian Perspective. Roger C. Wiens has a PhD in Physics, with a minor in Geology. His PhD thesis was on isotope ratios in meteorites, including surface exposure dating. First edition ; revised version Radiometric dating--the process of determining the age of rocks from the decay of their radioactive elements--has been in widespread use for over half a century.

There are over forty such techniques, each using a different radioactive element or a different way of measuring them. It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago. Further evidence comes from the complete agreement between radiometric dates and other dating methods such as counting tree rings or glacier ice core layers.

Many Christians have been led to distrust radiometric dating and are completely unaware of the great number of laboratory measurements that have shown these methods to be consistent. Many are also unaware that Bible-believing Christians are among those actively involved in radiometric dating. This paper describes in relatively simple terms how a number of the dating techniques work, how accurately the half-lives of the radioactive elements and the rock dates themselves are known, and how dates are checked with one another.

In the process the paper refutes a number of misconceptions prevalent among Christians today. This paper is available on the web via the American Scientific Affiliation and related sites to promote greater understanding and wisdom on this issue, particularly within the Christian community. Doubters Still Try Apparent Age? Rightly Handling the Word of Truth. Arguments over the age of the Earth have sometimes been divisive for people who regard the Bible as God's word. Even though the Earth's age is never mentioned in the Bible, it is an issue because those who take a strictly literal view of the early chapters of Genesis can calculate an approximate date for the creation by adding up the life-spans of the people mentioned in the genealogies.

Assuming a strictly literal interpretation of the week of creation, even if some of the generations were left out of the genealogies, the Earth would be less than ten thousand years old. Radiometric dating techniques indicate that the Earth is thousands of times older than that--approximately four and a half billion years old.

Many Christians accept this and interpret the Genesis account in less scientifically literal ways. However, some Christians suggest that the geologic dating techniques are unreliable, that they are wrongly interpreted, or that they are confusing at best. Unfortunately, much of the literature available to Christians has been either inaccurate or difficult to understand, so that confusion over dating techniques continues.

The next few pages cover a broad overview of radiometric dating techniques, show a few examples, and discuss the degree to which the various dating systems agree with each other. The goal is to promote greater understanding on this issue, particularly for the Christian community. Many people have been led to be skeptical of dating without knowing much about it. For example, most people don't realize that carbon dating is only rarely used on rocks.

God has called us to be "wise as serpents" Matt. In spite of this, differences still occur within the church. A disagreement over the age of the Earth is relatively minor in the whole scope of Christianity; it is more important to agree on the Rock of Ages than on the age of rocks. But because God has also called us to wisdom, this issue is worthy of study.

Rocks are made up of many individual crystals, and each crystal is usually made up of at least several different chemical elements such as iron, magnesium, silicon, etc. Most of the elements in nature are stable and do not change. However, some elements are not completely stable in their natural state. Some of the atoms eventually change from one element to another by a process called radioactive decay. If there are a lot of atoms of the original element, called the parent element, the atoms decay to another element, called the daughter element, at a predictable rate.

The passage of time can be charted by the reduction in the number of parent atoms, and the increase in the number of daughter atoms. Radiometric dating can be compared to an hourglass. When the glass is turned over, sand runs from the top to the bottom. Radioactive atoms are like individual grains of sand--radioactive decays are like the falling of grains from the top to the bottom of the glass. You cannot predict exactly when any one particular grain will get to the bottom, but you can predict from one time to the next how long the whole pile of sand takes to fall.

Once all of the sand has fallen out of the top, the hourglass will no longer keep time unless it is turned over again. Similarly, when all the atoms of the radioactive element are gone, the rock will no longer keep time unless it receives a new batch of radioactive atoms. Page 2. Figure 1. The rate of loss of sand from from the top of an hourglass compared to exponential type of decay of radioactive elements.

In exponential decay the amount of material decreases by half during each half-life. After two half-lives one-fourth remains, after three half-lives, one-eighth, etc. Unlike the hourglass, where the amount of sand falling is constant right up until the end, the number of decays from a fixed number of radioactive atoms decreases as there are fewer atoms left to decay see Figure 1. If it takes a certain length of time for half of the atoms to decay, it will take the same amount of time for half of the remaining atoms, or a fourth of the original total, to decay.

In the next interval, with only a fourth remaining, only one eighth of the original total will decay. By the time ten of these intervals, or half-lives, has passed, less than one thousandth of the original number of radioactive atoms is left. The equation for the fraction of parent atoms left is very simple. The type of equation is exponential, and is related to equations describing other well-known phenomena such as population growth.

No deviations have yet been found from this equation for radioactive decay. Also unlike the hourglass, there is no way to change the rate at which radioactive atoms decay in rocks. If you shake the hourglass, twirl it, or put it in a rapidly accelerating vehicle, the time it takes the sand to fall will change. But the radioactive atoms used in dating techniques have been subjected to heat, cold, pressure, vacuum, acceleration, and strong chemical reactions to the extent that would be experienced by rocks or magma in the mantle, crust, or surface of the Earth or other planets without any significant change in their decay rate.

In only a couple of special cases have any decay rates been observed to vary, and none of these special cases apply to the dating of rocks as discussed here. These exceptions are discussed later. An hourglass will tell time correctly only if it is completely sealed. If it has a hole allowing the sand grains to escape out the side instead of going through the neck, it will give the wrong time interval.

Similarly, a rock that is to be dated must be sealed against loss or addition of either the radioactive daughter or parent. If it has lost some of the daughter element, it will give an inaccurately young age. As will be discussed later, most dating techniques have very good ways of telling if such a loss has occurred, in which case the date is thrown out and so is the rock! An hourglass measures how much time has passed since it was turned over.

Actually it tells when a specific amount of time, e. Radiometric dating of rocks also tells how much time has passed since some event occurred. For igneous rocks the event is usually its cooling and hardening from magma or lava. For some other materials, the event is the end of a metamorphic heating event in which the rock gets baked underground at generally over a thousand degrees Fahrenheit , the uncovering of a surface by the scraping action of a glacier, the chipping of a meteorite off of an asteroid, or the length of time a plant or animal has been dead.

The Radiometric Clocks. There are now well over forty different radiometric dating techniques, each based on a different radioactive isotope. The term isotope subdivides elements into groups of atoms that have the same atomic weight. For example carbon has isotopes of weight 12, 13, and 14 times the mass of a nucleon, referred to as carbon, carbon, or carbon abbreviated as 12 C, 13 C, 14 C.

It is only the carbon isotope that is radioactive. This will be discussed further in a later section. A partial list of the parent and daughter isotopes and the decay half-lives is given in Table I. Notice the large range in the half-lives. Isotopes with long half-lives decay very slowly, and so are useful for dating. Table 1.

Some Naturally Occurring Radioactive Isotopes and their half-lives. Radioactive Isotope. Most half-lives taken from Holden, N. Isotopes with shorter half-lives cannot date very ancient events because all of the atoms of the parent isotope would have already decayed away, like an hourglass left sitting with all the sand at the bottom. Isotopes with relatively short half-lives are useful for dating correspondingly shorter intervals, and can usually do so with greater accuracy, just as you would use a stopwatch rather than a grandfather clock to time a meter dash.

On the other hand, you would use a calendar, not a clock, to record time intervals of several weeks or more. The half-lives have all been measured directly either by using a radiation detector to count the number of atoms decaying in a given amount of time from a known amount of the parent material, or by measuring the ratio of daughter to parent atoms in a sample that originally consisted completely of parent atoms.

Work on radiometric dating first started shortly after the turn of the 20th century, but progress was relatively slow before the late. However, by now we have had over fifty years to measure and re-measure the half-lives for many of the dating techniques. Very precise counting of the decay events or the daughter atoms can be done, so while the number of, say, rhenium atoms decaying in 50 years is a very small fraction of the total, the resulting osmium atoms can be very precisely counted.

For example, recall that only one gram of material contains over 10 21 1 with 21 zeros behind atoms. Even if only one trillionth of the atoms decay in one year, this is still millions of decays, each of which can be counted by a radiation detector! The uncertainties on the half-lives given in the table are all very small. There is no evidence of any of the half-lives changing over time.

In fact, as discussed below, they have been observed to not change at all over hundreds of thousands of years. Examples of Dating Methods for Igneous Rocks. Now let's look at how the actual dating methods work. Igneous rocks are good candidates for dating.

Radiometric dating, radioactive dating or radioisotope dating is a technique used to date . Radiometric dating has been carried out since when it was invented by Ernest Rutherford as a method by which .. abundance of 26Mg (the product of 26Al decay) in comparison with the ratio of the stable isotopes 27Al/24 Mg. B. a stable isotope to a decaying isotope. C. two nondecaying isotopes over time. D. the isotopes from two different elements over time. The answer should be B. a stable isotope to a decaying isotope.

Geologists use radiometric dating to estimate how long ago rocks formed, and to infer the ages of fossils contained within those rocks. Radioactive elements decay The universe is full of naturally occurring radioactive elements. Radioactive atoms are inherently unstable; over time, radioactive "parent atoms" decay into stable "daughter atoms. When molten rock cools, forming what are called igneous rocks, radioactive atoms are trapped inside. Afterwards, they decay at a predictable rate.

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Off the top of my head it substantiates that if you have 5 transitional fossils showing the slow change of an organism over a few million years that they did come in the order that they appear to, that one did spawn the other. I think the best evidence of macroevolution is in genetic … similarities between all life on earth, common descent. Radiometric dating proves nothing about any form of evolution since it is itself unreliable in the sense that it is based on three unprovable assumptions, and has also been found to be unreliable in the field in various circumstances.

Dating Fossils – How Are Fossils Dated?

Radiometric dating , radioactive dating or radioisotope dating is a technique used to date materials such as rocks or carbon , in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. Together with stratigraphic principles , radiometric dating methods are used in geochronology to establish the geologic time scale. By allowing the establishment of geological timescales, it provides a significant source of information about the ages of fossils and the deduced rates of evolutionary change. Radiometric dating is also used to date archaeological materials, including ancient artifacts. Different methods of radiometric dating vary in the timescale over which they are accurate and the materials to which they can be applied.


Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material. The stable form of carbon is carbon 12 and the radioactive isotope carbon 14 decays over time into nitrogen 14 and other particles. Carbon is naturally in all living organisms and is replenished in the tissues by eating other organisms or by breathing air that contains carbon. At any particular time all living organisms have approximately the same ratio of carbon 12 to carbon 14 in their tissues. When an organism dies it ceases to replenish carbon in its tissues and the decay of carbon 14 to nitrogen 14 changes the ratio of carbon 12 to carbon Experts can compare the ratio of carbon 12 to carbon 14 in dead material to the ratio when the organism was alive to estimate the date of its death. Radiocarbon dating can be used on samples of bone, cloth, wood and plant fibers. The half-life of a radioactive isotope describes the amount of time that it takes half of the isotope in a sample to decay.

Бринкерхофф ухмыльнулся. Деньги налогоплательщиков в действии.

То, что он собирался сделать, несомненно, было проявлением малодушия. Я умею добиваться своей цели, - подумал .

У вирусов есть линии размножения, приятель. Тут ничего такого. Сьюзан с трудом воспринимала происходящее. - Что же тогда случилось? - спросил Фонтейн.  - Я думал, это вирус. Джабба глубоко вздохнул и понизил голос. - Вирусы, - сказал он, вытирая рукой пот со лба, - имеют привычку размножаться. Клонировать самих.

Они глупы и тщеславны, это двоичные самовлюбленные существа. Они плодятся быстрее кроликов.

Неожиданно он оказался на открытом воздухе, по-прежнему сидя на веспе, несущейся по травяному газону. Задняя стенка ангара бесследно исчезла прямо перед. Такси все еще двигалось рядом, тоже въехав на газон. Огромный лист гофрированного металла слетел с капота автомобиля и пролетел прямо у него над головой. С гулко стучащим сердцем Беккер надавил на газ и исчез в темноте.

ГЛАВА 84 Джабба вздохнул с облегчением, припаяв последний контакт. Выключив паяльник, он отложил в сторону фонарик и некоторое время отдыхал, лежа под большим стационарным компьютером.

Джабба тяжко вздохнул. Он знал, что Фонтейн прав: у них нет иного выбора. Время на исходе. Джабба сел за монитор. - Хорошо. Давайте попробуем.

Да я бы ничего и не взял у умирающего. О небо. Только подумайте. Беккер встревожился: - Так кольца у вас. - Боже мой, конечно. Беккер ощутил тупую боль в желудке. - У кого же .

Следопыт? - Он, похоже, был озадачен.  - Следопыт вышел на Хейла. - Следопыт так и не вернулся. Хейл его отключил. И Сьюзан принялась объяснять, как Хейл отозвал Следопыта и как она обнаружила электронную почту Танкадо, отправленную на адрес Хейла.

Каждое послание состояло из числа букв, равного полному квадрату, - шестнадцати, двадцати пяти, ста - в зависимости оттого, какой объем информации нужно было передать. Цезарь тайно объяснил офицерам, что по получении этого якобы случайного набора букв они должны записать текст таким образом, чтобы он составил квадрат. Тогда, при чтении сверху вниз, перед глазами магически возникало тайное послание. С течением времени этот метод преобразования текста был взят на вооружение многими другими и модифицирован, с тем чтобы его труднее было прочитать.

Кульминация развития докомпьютерного шифрования пришлась на время Второй мировой войны.

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