The zodiac was of central significance in ancient religious conceptions. Christian scholarship has never considered the basic numbers which appear with much frequency in the Bible to have more than incidental importance.
Well before the written word the zodiac was the first graph of cosmogenesis. The sages of old discerned the fact that 3 + 4 equalled 7 and 3 X 4 equalled 12. The prime number 7 occurs ubiquitously in ancient scripture and the physical universe was thought to have been built on this number. The primacy of the number 12 meant that in ancient cosmogony the division of the year was divided into 12 periods of twenty 28 days. Adjustments came later to match the seasonal variation. 12 derived from the ancient cosmology – zodiac.
So the week was 7, and the month 28 days over a 12 month period.
We then get 40 days recurring time and time again – being the years of productive making, and 70 (three score and ten) being symbolic of one life opportunity. 7 X 70 weeks gave us Gabriel’s vision to Daniel that was taken from the years recorded in the Books of Kings and Chronicles – 490 years divided 7 + 62 (Pre-exilic) and +1 week (Post-exilic) = 70 weeks or 490 years.