Before radiometric dating
Before radiometric dating - who does brandon barash dating
Some [skeptics] make it sound like there is a lot of disagreement, but this is not the case.The disagreement in values needed to support the position of young-Earth proponents would require differences in age measured by orders of magnitude (e.g., factors of 10,000, 100,000, a million, or more).
And it has been close to a hundred years since the uranium-238 decay rate was first determined.
In part, these have been the result of natural factors, including the climatic changes of the Little Ice Age, and the Spörer and Maunder solar activity minima.
In addition, however, changes in human activity since the middle of the 19th century have released C that occurred prior to 1955 mean that a single radiocarbon date may yield an imprecise calibrated age consisting of several possible age ranges.
This difficulty may be overcome by obtaining a series of C dates from a sequence and either wiggle-matching these dates to a radiocarbon calibration curve or using additional information on dated materials and their surrounding environment to narrow the calibrated age ranges associated with each C levels between consecutive years offer the possibility of dating recent samples with a resolution of from one to a few years.
These approaches to dating the recent past are illustrated using examples from peats, lake and salt marsh sediments, tree rings, marine organisms and speleothems.
In a related article on geologic ages (Ages), we presented a chart with the various geologic eras and their ages.
In a separate article (Radiometric dating), we sketched in some technical detail how these dates are calculated using radiometric dating techniques.If two or more radiometric clocks based on different elements and running at different rates give the same age, that's powerful evidence that the ages are probably correct.Along this line, Roger Wiens, a scientist at the Los Alamos National Laboratory, asks those who are skeptical of radiometric dating to consider the following (quoted in several cases from [Wiens2002]): All of the different dating methods agree--they agree a great majority of the time over millions of years of time.The slope of the line determines the date, and the closeness of fit is a measure of the statistical reliability of the resulting date.Technical details on how these dates are calculated are given in Radiometric dating. As with any experimental procedure in any field of science, these measurements are subject to certain "glitches" and "anomalies," as noted in the literature.The differences actually found in the scientific literature are usually close to the margin of error, usually a few percent, not orders of magnitude!