Quote from futurecurrents:
That's right! YEC's actually believe it's ten thousand.
Where did a young-earth worldview come from?
Simply put, it came from the Bible. Of course, the Bible doesnât say explicitly anywhere, âthe earth is 6,000 years old.â Good thing it doesnât; otherwise it would be out of date the following year. But we wouldnât expect an all-knowing God to make that kind of a mistake.
God gave us something better. In essence, He gave us a âbirth certificate.â For example, using my personal birth certificate, I can calculate how old I am at any point. It is similar with the earth. Genesis 1 says that the earth was created on the first day of creation (Genesis 1:1â5). From there, we can begin calculations of the age of the earth.
Letâs do a rough calculation to show how this works. The age of the earth can be estimated by taking the first 5 days of creation (from earthâs creation to Adam), then following the genealogies from Adam to Abraham in Genesis 5 and 11, then adding in the time from Abraham to today.
Adam was created on Day 6, so there were 5 days before him. If we add up the dates from Adam to Abraham, we get about 2,000 years, using the Masoretic Hebrew text of Genesis 5 and 11.3 Whether Christian or secular, most scholars would agree that Abraham lived about 2,000 B.C. (4,000 years ago).
So a simple calculation is:
5 days
+ ~2000 years
+ ~4000 years
______________
~6000 years
When we start our thinking with Godâs Word, we see that the world is about 6,000 years old. When we rely on manâs fallible (and often demonstrably false) dating methods, we can get a confusing range of ages from a few thousand to billions of years, though the vast majority of methods do not give dates even close to billions.
http://www.answersingenesis.org/articles/2007/05/30/how-old-is-earth