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.
Young-earth proponents (biblical age of the earth and universe of about 6,000 years)1. Old-earth proponents (secular age of the earth of about 4.5 billion years and a universe about 14 billion years old)2.