Scientists first make observations that raise a particular question. In order to explain the observed phenomenon, they develop a number of possible explanations, or hypotheses. This is the inductive part of science, observing and constructing plausible arguments for why an event occurred.
As indicated earlier, the Bible does not fix the age of the earth, contrary to the claims of Answers in Genesis. Historically, their claim comes from the work of James Ussher, Bishop in the Church of Ireland, from 1625 to 1656.
The age of the earth has been a topic of debate among Christians over the last two centuries. Several Christian ministries promote the idea that the earth is less than 10,000 years old, which they say comes from the Bible. In reality, the Bible makes no claim as to the age of the earth, although it does establish a minimum age.