However, “changes in radioactive decay constant depending on the physical and chemical environment of the nuclide have been known for 40 years.” In particular a researcher . As the discovery was not of direct relevance to the research involved it was not published until 1994, when it appeared to have relevance to the problem of “cold fusion.” That test involved other radioactive elements, but it showed that radioactive decay rates can be altered, thus creating more uncertainty regarding the second of the facts essential to precise C14 dates. neutrino flux of the superexplosion must have had the peculiar characteristic of resetting all our atomic clocks.” Supernova 1987-A was studied carefully by scientists.Other things affecting decay rates were mentioned by G. It was the first exploded star close enough to Earth and large enough for detailed analysis—made possible by the emplacement of modern neutrino-detection equipment.Measuring the current levels of C14 in a specimen is—by far—the most precisely determinable of the four essential facts.With the advent of AMS technology, and the less-precise technique is often employed.The bold line at the 100% level represents the generally accepted assumption that for thousands of years the original content has been at the same level as what is observed in the atmosphere in modern times.The small box on the decay curve represents the current level of a particular once-living specimen, in this instance measured at 50% of its assumed original content.That assumption error causes C14 dates to appear “older” than the actual ages of the specimens dated.(See the “Assumption Error” section later in this paper for more details.) The decay rate of C14 is estimated by comparing measurements taken in the recent past with C14’s current radioactivity levels.
If an artifact is preserved from physical decay and leaching of chemicals, radioactivity may be the sole means whereby it gradually loses its C14. A simple analogy may be helpful: Suppose water is steadily dripping into a large tub.For example: “Nobody cites the many hundreds of C Carbon-14 is radioactive—therefore, it decays over time.It can be used as a dating tool because creatures and plants accumulate it during their lifetimes, and cease doing so when they die. If four essential facts are known, an age can be calculated with precision.They are: (1) the C14 concentration in a specimen at its time of death; (2) the decay rate of C14; (3) the current C14 concentration in the specimen being “dated”; and (4) if anything else has affected the specimen’s C14 content. The curved line represents the declining amount of C14 atoms over time due to radioactive decay.Note: only the third of those four necessary facts can be measured, the other three must be estimated, assumed, or extrapolated. During each half-life (~5,730 years), about half of the remaining C14 atoms in a specimen are expected to decay.