The Bible doesn't say exactly when the earth "began", just FYI. It says the earth was created in 7 days, but there are a lot of Christians who don't have a problem with that being a little vague. What determines a day when the sun wasn't created until the 4th "day", and the earth on the first? The sun determines that a day is 24 hours here, but it wasn't in existence until 3 days after earth was even created. How long could those days have actually been? The Bible also seems to imply that the earth was created in a "mature" state, so who's to say that in a Christian's mind (that believes the earth is 6 to 10,000 years old) the earth seeming to be 4.75 billion years old disproves anything? I'm not 100% sure about carbon dating, but I've heard and researched that it's not always the best measurement of time for objects that are seemingly very, very old. I think you have to have just as much faith in that system as it can't be proved as a fact. Anyways, all that to say, there are plenty of Christians that believe the 6 to 10,000 year thing is a little vague in the Bible bc of the order of events in the creation story.