1) There has always been as much carbon 14 in the atmosphere as there is today.

When scientists first started using carbon dating they assumed the earth's carbon 14 content had reached "equilibrium" That means a balance.
The sunlight was adding new carbon 14, while decay was taking it away. At first the earth would fill up with more and more carbon 14, but eventually the carbon 14 would be decaying as fast as it was being added.

It's the same principle with a barrel of water - Watch below as the water fills the barrel (you can try this at home with a plastic bottle or milk carton - Poke holes in it, with the holes from bottom to top. Put the carton in the sink and turn on the water very slowly . . . how far will the carton fill up with water? Try turning the water on a little more . . . now how far up the carton?


Unfortunately scientists are discovering that the earth is still "filling up" with carbon 14. So they really do not have an accurate measurment. Scientists do know from their studies that it would take 20,000 years for the earth to reach this balance in carbon 14 . . . What does that tell you about the age of the earth?