29. The biblical figure, unfortunately, is based on patriarchal life spans to which no right-thinking person could subscribe. You have to be pretty deep into biblical infallibility before you can make yourself believe that individuals once lived upwards of 900 years! Claims about the magical effects of vapor canopies and tropical living don't impress anyone who has the slightest understanding of the aging process.
More to the point, the patriarchal ages are nothing more than a modified version of an old Babylonian myth!
2. The Ages of the Patriarches ... are the modest Hebrew equivalents of the much longer lifespans attributed by the Babylonians to their antediluvian kings. The first five names will suffice as examples: Alulim reigned 28,800 years, Alamar 36,000, Enmenluanna 43,200, Enmenluanna 28,800, Dumuzi the Shepherd 36,000, etc. These Babylonian lists, a version of which is recorded also by Berosus, have one feature in common with the Biblical list of patriarches: they both attribute extremely long lifespans to the earliest figures, then shorter, but still unrealistically long, lives to the later ones, until the historical period is reached when both kings and patriarches are cut down to human size. In the ancient Near East, where longevity was considered man's greatest blessing, the quasi-divine character of early mythical kings and patriarches is indicated by a ten-fold, hundred-fold or thousand-fold multiplication of their reigns or ages.
(Graves and Patai, 1989, pp.132-133)
The source Lloyd Bailey uses (Text W-B 62, Sumerian King List) yields even higher ages for some of the pre-diluvian kings of Mesopotamia (Baily, 1989, p.123). It is interesting to note that Genesis has the same number of antediluvian kings, namely tem. Bailey spends several pages examining the figures of Genesis and of the above text, often turning up interesting subleties and odd relationships which expose the artificial nature of the biblical ages assigned to the patriarches.
Thus, we see the true source of the great ages of those biblical patriarches. Their ages are simply a Hebrew version of an older Mesopotamian tradition, which is to say that they are historically fictitious, that they are endowed with symbolic meanings.
Therefore, the biblical age of the earth is a product of the literary reworking of a Mesopotamian tradition and not the result of a factual estimate. The patriarches' ages were selected with symbolic meanings in mind, and any attempt to turn them into an estimate of the earth's age would be most unwise.