Carbon dating quotes
But in actual practice, we know neither the original ratios nor if the specimen has been contaminated and are forced to make what we hope are reasonable assumptions.The tiny initial amount of C14, the relatively rapid rate of decay (the half-life of C14 is currently about 5700 years) and the ease with which samples can become contaminated make radiocarbon dating results for samples "older" than about 50,000 years effectively meaningless.As you might guess, radioactive carbon (C) is quite rare.Only one out of every trillion carbon atoms is C14. The C14 created in the upper atmosphere reacts with oxygen to become carbon dioxide.Because atmospheric carbon 14 arises at about the same rate that the atom decays, Earth's levels of carbon 14 have remained fairly constant.Once an organism is dead, however, no new carbon is actively absorbed by its tissues, and its carbon 14 gradually decays. BASIS OF RADIOCARBON DATING Radiocarbon dating compares the amount of normal carbon with the amount of radioactive carbon in a sample. What effect would the declining strength of the earth's magnetic field and a catastrophic worldwide flood have on radiocarbon dates?
Most carbon consists of the isotopes carbon 12 and carbon 13, which are very stable.
Libby thus reasoned that by measuring carbon 14 levels in the remains of an organism that died long ago, one could estimate the time of its death.
This procedure of radiocarbon dating has been widely adopted and is considered accurate enough for practical use to study remains up to 50,000 years old.
Radioactive carbon (Carbon 14) is formed in the upper atmosphere as a byproduct of cosmic radiation.
Cosmic rays are positively charged atoms moving at enormous speeds.