Taking the King James Bible of 1611 and you add up all the dates from the present on back to creation you get about 6000 years of earth history. You Have the creation of earth at about 4000b.c and theres 1656 years from Adam to Noah's flood and then about another 2300 years to the time of Christ. and from the Christ's resurrection to the present day about another 2000 years. Christ was actually born abt 5b.c and died in 30 or 33a.d and 3 days later rose again from the dead :) and sources outside of the biblical account can be found in a book called The Archko Volume and also a book by Bill Cooper called After the Flood. According to the bible and the works of Austrlian Astronomer George Dodwell in his book The obliquity of the Ecliptic, Noah's flood happened in 2345b.c . The Tower of Babel took place inbetween the time of flood and the birth of Abraham. While i have yet to pinpoint an exact year, on the Sumerian Kings list, it happened in the days of Gilgamesh before 2119b.c in the days of Peleg Genesis 10:25 And unto Eber were born two sons: the name of one was Peleg; for in his days was the earth divided; and his brother's name was Joktan.

The name Joktan means Shortening of days which is why if you look at the kings list and also the bible; the average age of a human being drops significantly. In the kings list, it goes from several thousand down to only 30 in the days of Ur-Nungal, who was the son of the biblical Nimrod; also known as Gilgamesh in the list.

As far as the authorship to Genesis; it was actually written by 10 different people and Moses was only the editor, and 2 Timothy 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: