This challenge is mainly headed by Creationism which teaches a young-earth (YE) theory.
A young earth is considered to be typically just 6,000 years old since this fits the creation account and some dating deductions from Genesis.
This young age agrees with a literal reading of Scripture, but is at variance with the billions of years conventionally held.
Gary Loechelt has been a frequent critic of Humphreys’ procedures for calculating the young age by helium diffusion.
But two observations and two clues omitted from physics textbook discussions of radiodating show that these radioisotope “clocks” are broken.
First, scientists have observed that radioactive isotope (radioisotope) decay rates do fluctuate, including Th-228, Rn-22, and Si-32.
Additionally, location of the mid-1960s bomb peak provides information on recharge rate (Schlosser and others, 1988, 1989; Solomon and Sudicky, 1991; Solomon and others, 1992, 1993; Ekwurzel and others, 1994).