There were actually scientific calculations that were based on the rate that the earth would cool down that determined the earth was fairly young due to the core temperature. That was before anyone understood that nuclear decay was also a source of heat.

There's a line in the bible concerning the second coming, the last days, where Jesus said that no man knoweth when that day will be, but only the father.

To that I would add that no man knoweth the day of the beginning of the earth -of life, except the father. We humans are in way too big a rush to proclaim we know this or that. The scientific projections on the age of the earth have a large degree of approximation to them. I read about Christians saying that the earth began on (month) (day) and (year) with zero approximation - I forget the date specified but it was to the day.

Yeah, right.