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We thank you in advance for partnering with us in this small but significant way. All methods of radioactive dating rely on three assumptions that may not necessarily be true: It is assumed that the rate of decay has remained constant over time.
When a new fossil is discovered, geologists assign a date for when they think the plant or animal lived.
They normally use radiometric dating methods to date the fossil, and many promote these methods as being accurate.
explains: “Carbon-14 dating, also called radiocarbon dating, [is a] method of age determination that depends upon the decay to nitrogen of radiocarbon (carbon-14).
Carbon-14 is continually formed in nature by the interaction of neutrons with nitrogen-14 in the Earth’s atmosphere; the neutrons required for this reaction are produced by cosmic rays interacting with the atmosphere. is absorbed from the air by green plants and then passed on to animals through the food chain.
There are about two dozen decay pairs used for dating.
Uranium 235 decay to lead has a half-life of 713 million years, so it is well suited to dating the universe.
Carbon has unique properties that are essential for life on Earth.
Familiar to us as the black substance in charred wood, as diamonds, and the graphite in “lead” pencils, carbon comes in several forms, or isotopes.
One rare form has atoms that are 14 times as heavy as hydrogen atoms: carbon-14, or C ratio gets smaller.
other isotope pairs cover intermediate time periods between the spans for carbon 14 and uranium.
Some radiometric dating methods depend upon knowing the initial amount of the isotope subject to decay.