Radiocarbon dating a third radiocarbon revolution. Occasionally, radiocarbon dating techniques date an object of popular interest, for example the Shroud of Turin, a piece of linen cloth thought by some to bear an image of Jesus Christ after his crucifixion. Three separate laboratories dated samples of linen from the Shroud in 1988; the results pointed to 14th-century origins, raising doubts about the shroud's authenticity as an alleged 1st-century relic. Researchers have studied other radioactive isotopes created by cosmic rays to determine if they could also be used to assist in dating objects of archaeological interest; such isotopes include , , , ,
Kinetic isotope effect effects to be easily measured and interpreted. In contrast, secondary effects are generally very small for heavier elements and close in magnitude to the experimental uncertainty, which complicates their interpretation and limits their utility. In the context of isotope effects, "hydrogen" is frequently used to refer to the light isotope, protium (H), specifically. In the rest of this article, reference to "hydrogen" and "deuterium" in parallel grammatical constructions or direct comparisons between them should be interpreted as referring to protium and deuterium. The theory of kinetic isotope effects was first formulated by Jacob Bigeleisen in 1949. Bigeleisen's general formula for