Where Do All Those Billions of Years Come From in Darwinian Thinking?
The history of an idea is always revealing. In the 16th century, the Europeans began to discover the colored peoples of the world. They assumed that Noah and his family were white, so for the colored peoples to have survived the Genesis Flood, it must have been local. The Church regarded this as heresy.
Later, at the time of the Industrial Revolution, there was a great need for coal; this initiated a study of geological strata in order to locate coal seams. It was correctly recognized that rock strata were laid down as sediment in water. But it was assumed that the strata were laid down sequentially in a multiple number of local floods rather than simultaneously during one global flood. Thus, scientific justification was now added to racial bias to downgrade the Genesis Flood from global to local.
From 1820 to 1840, the various strata were found not only to be in roughly the same vertical order but also to extend from Ireland to Russia. Clearly a local river could not provide this much sediment, and the sea was the only other possible water source. However, having the sea level rise was an unacceptable explanation, since this would cause worldwide flooding. The only recourse was to have the entire continental land surfaces sink below sea level and then rise again. This had to happen a multiple number of times.
Geology textbooks speak of this as a "transgression of the sea," thereby avoiding as much as possible any mention of the land surface having to sink. However, there is no known mechanism for entire continents rising and falling, nor is there any evidence for it. It was argued that it all takes place so slowly as to be imperceptible. Thus, the millions of years became an essential part of a belief system.
It was assumed that the distribution of the fossils in the strata was perceived to represent a record of the evolution of life throughout earth's history. This notion had originally been proposed by the Greeks. But it was Charles Darwin who later provided a mechanism by which one life form was believed to have become another. The multiple millions of years were equally as essential to him for his theory to work. Again, the same argument was used for the evolution of life: it all takes place so slowly that it can't be seen.
Today virtually every scientific discipline from astronomy to zoology assumes the universe and our solar system to be billions of years old. Any one of the arguments for the long ages are extremely questionable and controversial. Nevertheless, each discipline believes the others have the firm data. There are, in fact, many evidences that indicate a youthful universe, but these are very seldom brought to the attention of the general public. The bottom line: there is no known method of finding an exact age.