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Carbon-14 Dating:     more books (17)

The carbon-14 dating of iro by Nikolaas J Van der Merwe, 1969 Carbon 14 Dating of Iron by VanDerMerweNikol, 1969 Carbon-14 Dating of Iron by N J Van Der Merwe, 1969-10-01 Carbon-14 dating by Willard F Libby, 1961 Preparation of water sample for carbon-14 dating (Circular) by H. R Feltz, 1963 The extraction of collagen under the Modified Longin Method with subsequent treatment by ninhydrin for use in Carbon 14 dating by Accelerator Mass Spectrometry techniques by Russell Tarver, 1995 Carbon 14 Dating of Iron by Nikol Van Der Merwe, 0000 Carbon 14 dating of some Arctic soils, (New Jersey. Agricultural Experiment Station, New Brunswick. Mimeographed note) by John C. F Tedrow, 1958 Carbon-14 and other Radioactive Dating Methods The carbon-14 method of age determination by Frank H. H Roberts, 1952 Radiocarbon dating of archaeological samples (sambaqui) using CO"2 absorption and liquid scintillation spectrometry of low background radiation [An article ... Journal of Environmental Radioactivity] by M.L.T.G. Mendonca, J.M. Godoy, et all Application of a new carbon-14 counting technique to earthquake studies (Open file report / U.S. Geological Survey) by Allen B Tucker, 1981 Carbon-14 counting by accelerator mass spectrometry: Application to earthquake dating by Allen B Tucker, 1985 Dendrochronologic calibration of the carbon-14 time scale by P. E Damon, 1972

lists with details

41. Carbon-14 Age Dating
    Carbon14 Age Dating. Since I'm credulous toward science and have takencarbon-14 dating for granted, I was unable to refute him.  
    http://www.exmormon.org/boards/honestboard/messages/990.html
    
    Extractions: Follow Ups Post Followup Exmormon.org- Honest Inquiry Message Board FAQ Posted by Hinge on July 09, 1998 at 18:00:49: I lost an argument with a TBAM - The 'A' is a profanity. He claimed that the age of the earth (or books, or skeletons) could not be accurately identified through carbon-14 age dating because of the amount of fossil fuels we have released into the atmosphere. He also rambled on about how God created the earth out of existing matter which may have been billions of years old. Since I'm credulous toward science and have taken carbon-14 dating for granted, I was unable to refute him. Furthermore, the articles I have read on the internet agree with the fossil fuel problem. Anyhow, is Carbon-14 Age Dating flawed? I thought it was substantially proven. Damn, I wish I would have taken that physics class serious when I was in college. : I lost an argument with a TBAM - The 'A' is a profanity. : He claimed that the age of the earth (or books, or skeletons) could not be accurately identified through carbon-14 age dating because of the amount of fossil fuels we have released into the atmosphere. : He also rambled on about how God created the earth out of existing matter which may have been billions of years old. : Since I'm credulous toward science and have taken carbon-14 dating for granted, I was unable to refute him. Furthermore, the articles I have read on the internet agree with the fossil fuel problem. : Anyhow, is Carbon-14 Age Dating flawed? I thought it was substantially proven. Damn, I wish I would have taken that physics class serious when I was in college.

42. Archaeological Dating
    One application is carbon14 dating. What has been discovered? Cancarbon-14 dating be used to estimate the age of the artifacts?  
    http://www.chem.duke.edu/~jds/cruise_chem/nuclear/dating.html
    
    Extractions: Significant progress has been made in this field of study since the discovery of radioactivity and its properties. One application is carbon-14 dating. Recalling that all biologic organisms contain a given concentration of carbon-14, we can use this information to help solve questions about when the organism died. It works like this..when an organism dies it has a specific ratio by mass of carbon-14 to carbon-12 incorporated in the cells of it's body. (The same ratio as in the atmosphere.) At the moment of death, no new carbon-14 containing molecules are metabolized, therefore the ratio is at a maximum. After death, the carbon-14 to carbon-12 ratio begins to decrease because carbon-14 is decaying away at a constant and predictable rate. Remembering that the half-life of carbon-14 is 5700 years, then after 5700 years half as much carbon-14 remains within the organism.

43. Re: Carbon-14 Dating Of Crude Oil
    Re carbon14 dating of crude oil. To radsafe@romulus.ehs.uiuc.edu; Subject Recarbon-14 dating of crude oil; From Khalid Aleissa kaleissa@kacst.edu.sa ;  
    http://www.vanderbilt.edu/radsafe/0001/msg00420.html
    
    Extractions: Date Prev Date Next Thread Prev Thread Next ... Thread Index http://www.ehs.uiuc.edu/~rad/radsafe.html http://www.ehs.uiuc.edu/~rad/radsafe.html Khalid Aleissa e-mail: kaleissa@kacst.edu.sa ************************************************************************ The RADSAFE Frequently Asked Questions list, archives and subscription information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html References Re: Carbon-14 dating of crude oil From: "Ron L. Kathren" <rkathren@tricity.wsu.edu> Prev by Date: journalists' (or reporters') ethics Next by Date: Re: C-14 and Petroleum Prev by thread: Re: Carbon-14 dating of crude oil Next by thread: Carbon-14 dating of crude oil Index(es): Date Thread

44. Re: Carbon-14 Dating Of Crude Oil
    Re carbon14 dating of crude oil. Prev by thread carbon-14 datingof crude oil; Next by thread Re carbon-14 dating of crude oil;  
    http://www.vanderbilt.edu/radsafe/0001/msg00164.html
    
    Extractions: Date Prev Date Next Thread Prev Thread Next ... Thread Index http://www.ehs.uiuc.edu/~rad/radsafe.html ************************************************************************ The RADSAFE Frequently Asked Questions list, archives and subscription information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html Follow-Ups Re: Carbon-14 dating of crude oil From: Prev by Date: Re: Nuclear Power vs CO2 Next by Date: The world's first commercial NPP Prev by thread: Carbon-14 dating of crude oil Next by thread: Re: Carbon-14 dating of crude oil Index(es): Date Thread

45. Layers Of A Lake Refine Carbon Dating
    Counting thin white layers of dead algae, each less than a millimeter thick,the researchers calibrated carbon14 dating back to 43,000 BC,  
    http://more.abcnews.go.com/sections/science/dailynews/carbon0220.html
    
    Extractions: At the bottom of Lake Suigetsu, thin layers of microscopic algae have been piling up for more than 45,000 years. Reading them like tree rings, scientists have improved their carbon-14 dating technique. (ABCNEWS.com) The rest of the year, dark clay sediments settle on the bottom. The alternating layers of dark and light count the years like tree rings. That has allowed scientists to fine-tune a technique called carbon-14 dating, which is used to pin down dates for artifacts tens of thousands of years old.

46. Carbon-14 Dating
    carbon14 dating. Carbon 14 dating is based on the ratio of carbon 14to carbon 12 and is generally used to date once-living material.  
    http://members.tripod.com/dineenadvbio98/carbondating.html
    
    Extractions: Carbon is an important in nature and is one of the basic elements found in all forms of life. It has three isotopes; two of these, carbon 12 and 13, are stable, whereas carbon 14 is radioactive. Carbon 14 has a half-life of 5,730 years plus or minus 30 years. Carbon 14 dating is based on the ratio of carbon 14 to carbon 12 and is generally used to date once-living material. Carbon 14 is constantly formed in the upper atmosphere through the activity of cosmic rays, which are high-energy particles (mostly protons). These high-energy particles strike the atoms of upper-atmospheric gases, splitting their nuclei into protons and neutrons. When a neutron strikes the nucleus of a nitrogen atom (atomic number 7, atomic mass number 14), it may be absorbed into the nucleus and a proton emitted. Thus, the atomic number of the atom decreases by one, while the atomic mass number stays the same. Because the atomic number has changed, a new element, carbon 14 (atomic number 6, atomic mass number 14), is formed. The newly formed carbon 14 is quickly assimilated into the carbon cycle and, along with carbon 12 and 13, is absorbed in a nearly constant ratio in all living organisms. Because carbon 14 is continually created in the upper atmosphere and distributed throughout the carbon cycle, the ratio of carbon 14 to carbon 12 remains constant in all living things. When an organism dies, however, carbon 14 is not replenished, and hence the ratio of carbon 14 to carbon 12 decreases as the carbon 14 decays.

47. Carbon Dating
    and so on. Although this technique looks good at first, carbon14 datingrests on two simple assumptions. They are obviously assuming  
    http://www.angelfire.com/nt/fairytales/carbon.html
    
    Extractions: Let me first explain how carbon dating works and then show you the assumptions it is based on. Nothing on earth carbon dates in the millions of years, because the scope of carbon dating only extends a few thousand years. Willard Libby invented the carbon dating technique in the early 1950’s. He calculated the amount of carbon-14 in the atmosphere today (about .0000765%), and assumed there would be the same amount found in living plants or animals since the plants breathe CO2 and animals eat plants. Carbon 14 is the radio-active version of carbon. Radiation from the sun strikes the atmosphere of the earth all day long. This energy produces radioactive carbon 14. This radioactive carbon 14 slowly decays into normal, stable carbon 12. Extensive laboratory testing has shown that about half of the C-14 molecules will decay in 5730 years. After another 5730 years half of the remaining C-14 will decay leaving only ¼ of the original C-14. It goes from ½ to ¼ to 1/8, etc. In theory it would never totally disappear, but after about 5 half lives the difference is not measurable with any degree of accuracy. This is why most people say carbon dating is only good for objects less than 30,000 years old.

48. Claim 1 - Radiometric Dating Is Inaccurate
    One example of which you might have heard is carbon14 dating, whichis used for dating of biological samples such as bones. The  
    http://www.ast.cam.ac.uk/~cmf/evolution/claim1.html
    
    Extractions: Radiometric dating is one of the processes by which the age of the Earth has been determined. One example of which you might have heard is Carbon-14 dating, which is used for dating of biological samples such as bones. The principle for this technique is rather simple. Carbon-14 is produced at a reasonably constant rate in the upper atmosphere. Living animals have a known level of Carbon-14 in their bodies as they breathe it in all the time from the air. They also have other, stable varieties ("isotopes") of carbon, such as Carbon-12, which is far more common. In a living creature, the ratio of abundance of these two substances simply reflects that in the atmosphere, and is therefore well-known. If this animal then dies and therefore is not able to gather more Carbon-14 then the ratio of the two elements will start to change as the Carbon-14 decays into a more stable form, such as Carbon-12 or Carbon-13. This is known to happen with a half-life of about 5,700 years, which means that after 5,700 years, the amount of Carbon-14 in a sample should have decayed by a factor of 2. If we know the original proportions of Carbon-14 and Carbon-12, and we can measure their ratio at a later date then we can work out how much of the Carbon-14 has decayed, and hence we can guess the age of the sample. Carbon-14 dating is typically used to date archaeological remains, especially from iron- and bronze-age sites of a few thousand years in age. Results are generally quoted to within 5 or 10 percent, and the ages thus obtained are usually in good agreement with the expected ages of the samples. Carbon-14 dating cannot be used to date remains older than about 50,000 to 60,000 years because the level of Carbon-14 in the sample will then be far too low for an accurate determination.

49. Carbon-14
    Carbon14 Radioactive Dating. carbon-14 dating technique is useful fororganic materials up to 50 000 years old (about 10 half-lives).  
    http://www.sciencebyjones.com/carbon-14.htm
    
    Extractions: Carbon-14 Radioactive Dating stable nitrogen in atmosphere + cosmic ray particle electron capture takes place carbon in atmosphere forms CO 13 % is carbon-14 87% is carbon-12 all living things take in CO till death upon death carbon-14 starts to decay (beta decay) at regular rate to stable nitrogen-14 Half-life: t average length of time needed for 1/2 the mass of radioactive sample to decay into a different substance 1 half-life for carbon-14 is 5730 years. carbon-14 dating technique is useful for organic materials up to 50 000 years old (about 10 half-lives) technique has been checked by tree rings (chronodendrology) and super novas technical name for process is neutron induced decay calculations: amount radioactive remaining original amount n n = number of half-lives Problems: Given 2.40 grams of a radioactive substance, calculate the amount of original radioactive sample remaining and the amount of material decay after 6 half-lives. Given 400. grams of a radioactive substance, calculate the number of half-lives that would have to pass for only approximately 10 grams to remain radioactive. Page Last Updated: Monday November 19, 2001 Webmaster:

50. What About Carbon-14 Dating? An Article Regarding Science And The Earths Age
    The chart that follows is a simplified explanation of how Carbon14 is formed,utilized, and used as a dating method. Other Factors To Consider About C-14.  
    http://www.hot2shop.com/carbon-14.html
    
    Extractions: Radiometric Dating Methods - Are They Reliable? Romans 3:4 Is any method of dating reliable that gives millions or billions of years when the Bible indicates that God created everything about 6,000 years ago? Clearly, if we just believe that absolutely reliable book called the Bible, we must reject the fallible, changeable, thoughts of men who are opposed to God and His word. However, because we are constantly challenged by scientists, the media, government schools, and other lost men with these so-called millions of years, we should at least find out the fallacies of their methods of dating. Carbon 14. Carbon is a basic element in our environment that occurs in many different forms. It is essential to life and the continuance of life here on earth. Diamonds, pencil lead, charcoal are just some of the substances that contain carbon. Carbon-14 is one of the rare forms of carbon that is formed by processes inherent in our universe. The chart that follows is a simplified explanation of how Carbon-14 is formed, utilized, and used as a dating method.

51. Sci.skeptic FAQ Creation Versus Evolution
    They hold that modern science has misinterpreted the evidence aboutthe age of the universe. Top 5.3 What about carbon14 dating?  
    http://home.xnet.com/~blatura/skep_5.html
    
    Extractions: 5.1: Is the Bible evidence of anything? Apart from the beliefs of those who wrote it, no. It is true that most Christians take the truth of at least some parts of the bible as an article of faith, but non-Christians are not so constrained. Quoting the bible to such a person as "evidence" will simply cause them to question the accuracy of the bible. See the alt.atheism FAQ lists for more details. Some things in the bible are demonstrably true, but this does not make the bible evidence, since there are also things in the bible that are demonstrably false. 5.2: Could the Universe have been created old? An argument is sometimes put forward along the following lines: We know from biblical evidence (see above) that the Universe is about 6,000 years old. Therefore God created it 6,000 years ago with fossils in the ground and light on its way from distant stars, so that there is no way of telling the real age of the Universe simply by looking at it. This is the "Omphalos" (Navel) theory of Edmund Gosse. Adam had no mother so did not need a navel, but was created by God with one, i.e. physical proof of connection with a nonexistent mother. Similarly, at the moment of Creation the world was chock-full of things that must have happened yesterday, when yesterday did not exist. The hypothesis is unfalsifiable, and therefore not a scientific one (see the section on the scientific method). It could also be made for any date in the past (like last Tuesday). Finally it requires that God, who is alleged to speak to us through His Works, should be lying to us by setting up a misleading Creation. This seems to be rather inconsistent with Biblical claims of God being the source of all truth.

52. Collapse -- Chaco Canyon
    For example, the arrival of sophisticated carbon14 dating methods in the 1940scaused scientists to revise their interpretation of events in Europe in  
    http://www.learner.org/exhibits/collapse/chacocanyon_sub.html
    
    Extractions: Dating the Evidence Accurate dating is important for putting events and objects in sequence. For example, the arrival of sophisticated carbon-14 dating methods in the 1940s caused scientists to revise their interpretation of events in Europe in prehistoric times. Ancient sites in England, Malta, and elsewhere turned out to be older than once thought. With this new information, scientists were able to paint a more accurate picture of European prehistory. Dating methods can be relative or absolute. An absolute dating method tells the excavator the specific date of the material being studied (plus or minus a margin of error). Imagine an archaeologist needs to assign a date to a bone recovered during an excavation. Turning to carbon-14 dating, the archaeologist might discover that the bone dates from 3,500 years ago. Adding the margin of error for carbon-14 (in this case, +/- 150 years), the archaeologist can give a reliable date range for the bone: 1655-1405 B.C. Relative dating is more inexact, but still useful. It involves putting things into a sequence based on their relative ages. A bone found deep in the ground will generally be older than one found close to the surface, for example. Two bones found in the same archaeological deposit are likely to be the same age. This sort of information helps archaeologists to put objects into an age sequence. Relative dating does not give archaeology absolute dates that can be tied into a calendar.

53. Carbon-14 Dating
    ?14? carbon-14 dating. Rubidium  
    http://www.qsl.net/vr2ls/Carbon-14/Carbon-14.html
    
    Extractions: ¥Ñ¦t©z®g½u¦Ó²£¥Íªº »P±a¦³¿ç®gªº ªº¤ñ²v³£´X¥G¬O«í©w¤£ÅÜ¡A¤j¬ù¬O¨C¤@¦Ê»õ²É ­ì¤l´N¦³¤@²É ¬O¥H¤@­Ó«í©w³t²v¥Ñ·s¥Íªº ©Ò¸É¥R¨Ã¥Ñ¦UºØ¥Í©RÅ餣°±ªº§l¦¬µÛ¡C¬G¦¹¡A¦b§Ú­Ì¨­Å餺©Òªº§t »P¦UºØ°Ê´Óª«¤¤¤]³£¬O¦P¤@­Ó¦Ê¤À²v¡C¦Ü¦¹¬Û«H¦³³¡¥÷Áo©úªºHAM¤Í¤w¸g²q¨ì¬ì¾Ç®a¨ì©³¬O¦p¦ó¥H ¨Ó´ú©w¤@­Ó¤ì¤D¥ìªº¦~¥÷¨Óªº¤F¡C ¨ÓŲ©w¤@¥ó¥jª« ¤F¡C·íµM¡A¦b¨º­Ó¥Í©RÅ馺¤`®Éªº¤@¨è¡A¥¦¤º¸Ìªº »P ªº¤ñ²v¤´µM¬O»P¨ä¥Lªº¥Í©RÅé©Ò§tªº¤ñ²v¬O¤@¼Ë¡A¦ý¥Ñ©ó ¡C§Y¬O»¡¡A¸Ó¥Í©RÅ馺¤`®É©Ò§tªº «h¦]¬°¦bí©wºA¤U¦Ó«O«ù¤£ÅÜ¡C©ó¬O¥G¡A¥ÎÆF±Óªº¿ç®gÀË´ú»ö¾¹´ú¥X¸Ó¥jª«¤¤ ªº§t¶qµM«áºâ¥X¥¦©M¸Ó¥jª«¤¤ªº ©M ªº¤ñ²v¨Ó¤ñ¸û¤@¤U¡A¦ÛµM´N¥i±o¨ì¤@­Ó¬Û·í·Ç½Tªº¦~¥÷®t§O¨Ó¤F¡C t¡×[ln (N f /N o ) / (-0.693)] x T ln ´N¬O¦ÛµM¹ï¼Æ (natural logarithm)

54. Carbon Dating Background
    carbon14 dating Background Information. _. t= 13,238 years old. Will carbon-14 dating work on all artifacts? No.  
    http://www.acad.carleton.edu/curricular/BIOL/classes/bio302/Pages/CarbonDatingBa
    
    Extractions: Carbon-14 Dating: Background Information Carbon dating is used to determine the age of biological artifacts up to 50,000 years old. This technique is widely used on recent artifacts, but teachers should note that this technique will not work on older fossils (like those of the dinosaurs which are over 65 million years old). This technique is not restricted to bones; it can also be used on cloth, wood and plant fibers. Carbon-14 dating has been used successfully on the Dead Sea Scrolls, Minoan ruins and tombs of the pharohs among other things. What is Carbon-14? Carbon-14 is a radioactive isotope of carbon. Its has a half-life of about 5,730 years. The short half-life of carbon-14 means its cannot be used to date extremely old fossils. Levels of carbon-14 become difficult to measure and compare after about 50,000 years (between 8 and 9 half lives; where 1% of the original carbon-14 remains undecayed). How is Carbon-14 formed? Carbon-14 is created from nitrogen-14 in the upper atmosphere of the earth. Radiation from the sun collides with atoms in the atmosphere. These collisions create secondary cosmic rays in the form of energentic neutrons. When these neutrons collide with nitrogen-14 in the atmosphere carbon-14 can be created. Nitrogen normally occurs in a seven proton, seven nuetron, nitrogen-14 state. When it collides with an energetic neutron it becomes carbon-14, with six protons and eight neutrons and gives off a hydrogen atom with one proton and zero neutrons.

55. 14C Methode
    This is called carbon14. carbon-14 decays at a gradual but steady rate, which lasts material carelessly thrown away in prehistory may become important for dating purposes.  
    http://webmuseen.de/14C.html
    
    Extractions: Space is filled with cosmic rays penetrating the upper layers of our earth's atmosphere. Atomic nuclei hit by these rays are split into their components. These fragments, flying apart with high velocity, collide with other nuclei. If a neutron hits a nitrogen nucleus another particle will be released by the latter. This particle is a positive loaded proton. Nitrogen becames Carbon. Der Kern des verwandelten Atoms hat jedoch 14 Teilchen, nicht 12 wie normaler Kohlenstoff. Man nennt ihn daher Kohlenstoff-14. Es ist eine Verwandlung auf Zeit, die irgendwann durch radioaktiven Zerfall endet. Aber das kann Tausende von Jahren dauern. The nucleus of the transformed atom possesses 14 particles, not 12 like normal Carbon. This is called Carbon-14. Carbon-14 decays at a gradual but steady rate, which lasts thousands of years. Carbon-14 is distributed evenly in the biosphere by weather activity. With time there is a balance between decaying atoms and atoms coming into being.

56. BBC - History - Archaeology - Carbon Dating
    Radio carbon dating determines the age of ancient objects by meansof measuring the amount of carbon14 there is left in an object.  
    http://www.bbc.co.uk/history/archaeology/carbondating_1.shtml
    
    Extractions: Radio carbon dating determines the age of ancient objects by means of measuring the amount of carbon-14 there is left in an object. A man called Willard F Libby pioneered it at the University of Chicago in the 50's. In 1960, he won the Nobel Prize for Chemistry. This is now the most widely used method of age estimation in the field of archaeology. Certain chemical elements have more than one type of atom. Different atoms of the same element are called isotopes. Carbon has three main isotopes. They are carbon-12, carbon-13 and carbon-14. Carbon-12 makes up 99% of an atom, carbon-13 makes up 1% and carbon-14 - makes up 1 part per million. Carbon-14 is radioactive and it is this radioactivity which is used to measure age. Radioactive atoms decay into stable atoms by a simple mathematical process. Half of the available atoms will change in a given period of time, known as the half-life. For instance, if 1000 atoms in the year 2000 had a half-life of ten years, then in 2010 there would be 500 left. In 2020, there would be 250 left, and in 2030 there would be 125 left.

57. The UnMuseum - Radiocarbon Dating
    meant if Libby found a sample where the amount of carbon14 was only Though archaeologistscould not directly use radiocarbon dating on objects such as coins  
    http://unmuseum.mus.pa.us/radiocar.htm
    
    Extractions: A Bristlecone Pine high in the mountains of California. Radiocarbon Dating Until the middle of the twentieth century archaeologists had a real problem. If they found a bit of pottery, an old coin, or another object while digging up a site, just how old was it? How could they tell if the object had been dropped on the ground thirty years ago or thirty centuries ago? In general, archaeologists knew that the farther they had to dig down to find an object, the older it probably was and that objects found at the same level, or stratum, were close in age. That was helpful when comparing the relative ages of two items, but how could they get the actual age? And how could they compare the ages of items found at sites fifty miles apart? If a society had written records the archaeologists could compare the history against the type of objects they were finding in the ground. A coin bearing the likeness of Augustus Caesar certainly couldn't have minted before Caesar started his reign. Likewise an Egyptian piece of pottery with a design depicting horse and chariot couldn't have been made before the horse was introduced to Egypt. Using these types of clues archaeologists were able to construct a firm history for some societies. By matching pottery between a culture with a known chronology against one without, they could even hazard a guess about historical dates when there were no records. This still left scientists wondering about the age of sites where neither cross-matching of pottery or written records could be used. That was, until the invention of radiocarbon dating.

58. Carbon 14 Dating
    Radiocarbon dating is based on the rate of decay of the unstable carbon14 whichis produced by cosmic radiation of neutrons in the upper atmosphere acting on  
    http://www.duke.edu/~clc8/radiocarbon.html
    
    Extractions: Since plants and animals intake carbon throughout their lives, the amount of 14C in their bodies remains in equilibrium with the atmospheric levels of 14C throughout their lifetime. When a plant or animal dies, it stops intaking carbon dioxide and the amount of 14C present in their body is reduced as the 14C decays and no additional 14C is incorporated to replace it. This unstable carbon-14 decays by the following process: The amount of time it takes for half of all the radioactive carbon to decay is referred to as the half-life. If one knows the atmospheric level of 14C and measures the amount of 14C in an organic sample, one can calculate the number of half lifes that have elapsed since the organism died and estimate the how long ago the organism died. Since the half-life of carbon is approximately 5730 years, this method is best used to date objects under 60,000 years old because after 10 or so half-lives there is just not enough 14C left to be measured accurately. There are other radioactive elements with longer half-lives that can be used to measure older samples.

59. Dead Sea Scroll Dating
    determined by the carbon14 measurements,'' the Israel Antiquities Authority statedin a news release. ``The reliability of paleography as a dating method is  
    http://packrat.aml.arizona.edu/deadsea.html
    
    Extractions: The Arizona Daily Star UA researchers have carbon 14-dated bits of the Dead Sea Scrolls, and the results discredit the controversial theory that some of the texts may have been the work of early Christians. That theory was based in part on the contents of a scroll that University of Arizona researchers said was made before Christ was born. The scrolls consist of some 800 manuscripts in Hebrew and Aramaic that were discovered in caves east of Jerusalem, near the ruins of Qumran on the Dead Sea, between 1947 and 1956. They include the oldest known manuscripts of books from the Old Testament, and their discovery is considered one of the great archaeological finds of the century. Traditionally, the scrolls are viewed as the work of an ascetic Jewish sect, the Essenes, who lived in a monastery near the caves between about 200 B.C. and 100 A.D. ``But there is a school of thought that says that some of these scrolls - the Habakkuk in particular - refer to some Christian leader, maybe Christ or John the Baptist,'' said UA researcher A.J. Timothy Jull. A commentary on the first two chapters of the biblical Book of Habakkuk was one of the 18 texts dated at the UA lab. The results, announced yesterday in Tucson and Jerusalem, have been submitted for publication in the journal Atiqot and elsewhere.

60. Carbon Dating
    In order for Carbon dating to have any value, carbon14, produced in our outer atmosphereas Nitrogen-14 and changed into radioactive carbon-14 by cosmic-ray  
    http://www.carbon-dating.net/
    
    Extractions: Carbon Dating is one of many Radiometric Dating techniques . As such, it shares some of the controversial assumptions fundamental to Radiometric Dating, such as (i) a constant rate of decay, (ii) no loss or gain of parent or daughter elements during decay, and (iii) known amounts of daughter elements present at the beginning of decay. Carbon Dating is often confused with other radiometric techniques, which place the ages of inorganic material in the millions or billions of years. As shown above, Carbon Dating is only used to date organic matter and is unable to determine the age of anything exceeding 60,000 years old. Carbon Dating: The Controversy Carbon Dating is actually more controversial than other radiometric dating techniques, in that it makes an additional major assumption. In order for Carbon Dating to have any value, Carbon-14, produced in our outer atmosphere as Nitrogen-14 and changed into radioactive Carbon-14 by cosmic-ray bombardment, must be at equilibrium in our atmosphere. That is, the production rate must be equal to the decay rate. Based on the mathematics inherent in Libby's research, it takes approximately 30,000 years of Carbon-14 build up from a zero concentration level to reach this state of equilibrium. Recent studies indicate that Carbon-14 has not yet reached equilibrium in our atmosphere, thus indicating that the atmosphere is not yet 30,000 years old. Carbon Dating: The Use Of Dendrochronology

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