Saturday, January 23, 2010

Review of "The Young Earth" by John Morris

Dr. Jellison provides another review of a 'creation science' book, Dr. John Morris' “The Young Earth: The Real History of the Earth - Past, Present, and Future”

Dr. Jellison focuses on issues of physics where he is more familiar, particularly radioisotope dating 'discrepencies' in recent lava flows and meteorites, which creationists commonly like to exploit.  For the lava flows, he points out that the dating studies Darylmple used in 1969 were not isochron dating methodologies.  Flows dated using isochron dating are much more in line with expected results.  There is an excellent treatment of isochron dating at talkorigins.org which illustrates how the isochron mechanism corrects for the problems like unknown initial concentrations and diffusion of parent and daughter products.

The cavalier attitude of creationists when dealing with real data is revealed in this description of Isochron Dating on CreationWiki.  In the third graph from the bottom of the page, they present an example of points far off the isochron.  CreationWiki seems to be claiming that dropping the 'bad' data points is a legitimate scientific practice (I remember some school teachers who, incorrectly, claimed it was okay to drop 'outliers' in a set of data).  It is not legitimate practice to drop a point in the result just because it is an outlier.  However, samples can be dropped from an analysis should it be demonstrated that there is some irregularity in the sampling protocol.

However, the proper scientific approach is to fit the slope of all the data.  The spread in the points of the 'isochron' generate the error bar (Wikipedia), or uncertainty, of the measurement.  In the case of the isochron, the outliers would make the uncertainty far larger than for points which cluster tight around the fitted line.  Modern practice has more consistently enforced for all researchers to report the best fit and uncertainty of the fit. 

Jerry also discusses the popular creationist claim of accelerated radioactive decay.  I  have some additional details on accelerated radioactive decay, including discussions of modern experiments which demonstrate methods of altering nuclear decay rates: “Claims of Accelerated Radioactive Decay”.

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