Radioactive decay dating video
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This assumption is backed by numerous scientific studies and is relatively sound.
However, conditions may have been different in the past and could have influenced the rate of decay or formation of radioactive elements.
While there is no proof that the rates were different in the past than they are today, there is also no proof that they were the same.
Thus radioactive dating relies purely on assumptions.
Many examples from literature show that the zero-reset assumption is not always valid.
Volcanic ejecta of Mount Rangitoto (Auckland, New Zealand) was found to have a potassium-40 age of 485,000 years, yet trees buried within the volcanic material were dated with the carbon-14 method to be less than 300 years old.
Sometimes only one method is possible, reducing the confidence researchers have in the results. “They’re based on ‘it’s that old because I say so,’ a popular approach by some of my older colleagues,” says Shea, laughing, “though I find I like it myself as I get more gray hair.” Kidding aside, dating a find is crucial for understanding its significance and relation to other fossils or artifacts.For more on this subject, see the video Bones in Stones i. Ogden III, "Annals of the New York Academy of Science," 288 (1977): 167-173. When it comes to determining the age of stuff scientists dig out of the ground, whether fossil or artifact, “there are good dates and bad dates and ugly dates,” says paleoanthropologist John Shea of Stony Brook University.They will argue that the clock was not reset if the age is too old, or that isotopes were selectively removed if the age turns out to be too young.In the study on the Hawaii lava flow cited above, it was argued that entrapment of excessive amounts of argon gas had made the samples appear older than they were.