In a related article on geologic ages (Ages), we presented a chart with the various geologic eras and their ages.
Dating schemes based on rates of radioactivity have been refined and scrutinized for several decades.
Other creationists have focused on instances in which radiometric dating seems to yield incorrect results.
In most instances, these efforts are flawed because the authors have misunderstood or misrepresented the data they attempt to analyze (for example, Woodmorappe 1979; Morris HM 1985; Morris JD 1994).
The unswerving regularity of this decay allows scientists to determine the age of extremely old organic materials -- such as remains of Paleolithic campfires -- with a fair degree of precision.
The decay of uranium-238, which has a half-life of nearly 4.5 billion years, enabled geologists to determine the age of the Earth.