That is not "mainstream Christian opinion." That is a fundamentalist view of the Bible as literal, historical truth. " Very conservative Protestant theologians is the way it was phrased in the link I provided.
The Catholics don't believe that, and they're pretty mainstream, aren't they?
Hey I'll be the first to admit I don't know all the different versions. No doubt you are correct that others have other times set. I can only say that every time I've ever personally heard a time presented in a religious type statement the earth was said to be 6 to 10 thousand years old.
Just for curiosity how old do the others say it is. Science says it's like 4.5 billion years old... anything close to that?
When I looked it up I came up with this as the debate...
In the beginning God created the heavens and the earth (Genesis 1:1).
The question of the age of the earth has produced heated discussions on debate boards, classrooms, TV, radio, and in many churches, Christian colleges, and seminaries. The primary sides are:
■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
The difference is immense! Let’s give a little history of where these two basic calculations came from and which worldview is more reasonable.
Where did a young-earth worldview come from?
Simply put, it came from the Bible. Of course, the Bible doesn’t say explicitly anywhere, “the earth is 6,000 years old.” Good thing it doesn’t; otherwise it would be out of date the following year. But we wouldn’t expect an all-knowing God to make that kind of a mistake.
God gave us something better. In essence, He gave us a “birth certificate.” 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 1:1–5). From there, we can begin calculations of the age of the earth.
Let’s 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 earth’s 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
At this point, the first 5 days are negligible. Quite a few people have done this calculation using the Masoretic text (which is what most English translations are based on) and, with careful attention to the biblical details, have arrived at the same time-frame of about 6,000 years, or about 4,000 B.C. Two of the most popular, and perhaps the best in my opinion, are a recent work by Dr. Floyd Jones and a much earlier book by Archbishop James Ussher (1581–1656):