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he question of the ages of the Earth and its rock formations and features has fascinated philosophers, theologians, and scientists for centuries, primarily because the answers put our lives in temporal perspective.Until the 18th century, this question was principally in the hands of theologians, who based their calculations on biblical chronology.How radiometric dating works in general Why methods in general are inaccurate Why K-Ar dating is inaccurate The branching ratio problem How Errors Can Account for the Observed Dates Why older dates would be found lower in the geologic column especially for K-Ar dating Do different methods agree with each other on the geologic column?Possible other sources of correlation Anomalies of radiometric dating Why a low anomaly percentage is meaningless The biostrategraphic limits issue Preponderance of K-Ar dating Excuses for anomalies Need for a double-blind test Possible changes in the decay rate Isochrons Atlantic sea floor dating Dating Meteorites Conclusion Gentry's radiohaloes in coalified wood Carbon 14 dating Tree ring chronologies Coral dating Varves Growth of coral reefs Evidence for catastrophe in the geologic column Rates of erosion Reliability of creationist sources Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive elements such as uranium, strontium, and potassium.After the second half-life has elapsed, yet another 50% of the remaining parent isotope will decay into daughter isotopes, and so on.For all practical purposes, the original isotope is considered extinct after 6 half-life intervals. A small portion of a meteorite is vaporized in the device forming ions.These ions are accelerated in an electric field through collimating slits and subject to a magnetic field which causes the ions to follow a curved path. By adjustment of the strength of the magnetic field and suitable placement of an ion collector, the different isotopes can be measured with precision.There are some things that affect these measurements.
We are told that these methods are accurate to a few percent, and that there are many different methods.
Lord Kelvin and Clarence King calculated the length of time required for the Earth to cool from a white-hot liquid state; they eventually settled on 24 million years.
James Joly calculated that the Earth’s age was 89 million years on the basis of the time required for salt to accumulate in the oceans.
Bishop James Ussher, a 17th-century Irish cleric, for example, calculated that creation occurred in 4004 B. There were many other such estimates, but they invariably resulted in an Earth only a few thousand years old.
By the late 18th century, some naturalists had begun to look closely at the ancient rocks of the Earth.
Its crust is continually being created, modified, and destroyed.