Willard Libby invented the carbon dating technique in the early 1950's.The amount of carbon 14 in the atmosphere today (about .0000765%), is assumed there would be the same amount found in living plants or animals since the plants breath CO2 and animals eat plants. Since sunlight causes the formation of C-14 in the atmosphere, and normal radioactive decay takes it out, there must be a point where the formation rate and the decay rate equalizes. Let me illustrate: If you were trying to fill a barrel with water but there were holes drilled up the side of the barrel, as you filled the barrel it would begin leaking out the holes.In order to find the length of time since the candle was lit we would be forced to make some assumptions.We would, obviously, have to assume that the candle has always burned at the same rate, and assumes an initial height of the candle. Similarly, scientists do not know that the carbon-14 decay rate has been constant.Radiation from the sun strikes the atmosphere of the earth all day long.This energy converts about 21 pounds of nitrogen into radioactive carbon 14.Since so many wrong dates are found, how would we know which dates are "correct? Then skull #KNM-ER 1470 was found (in 1972) under the KBS tuff by Richard Leakey. 1999 Lava from the 1801 Hawaiian volcano eruption gave a K-Ar date of 1.6 Million years old. B., 1969 40Ar/36Ar analysis of historic lava flows. There are about 7 or 8 radioactive elements that are used today to try to date objects. A hominid species assumed to be an ancestor of Homo sapiens, erectus was thought to have vanished some 250,000 years ago. "Structure, metamorphism, sedimentary reworking, and other complications have to be considered.
Let me first explain how carbon dating works and then show you the assumptions it is based on.This radioactive carbon 14 slowly decays back into normal, stable nitrogen.Extensive laboratory testing has shown that about half of the C-14 molecules will decay in 5730 years. After another 5730 years half of the remaining C-14 will decay leaving only ¼ of the original C-14. In theory it would never totally disappear, but after about 5 half lives the difference is not measurable with any degree of accuracy.A very small percentage of the carbon plants take in is radioactive C-14.