Carbon-14 has a half-life of 5,730 ± 40 years— during the succeeding 5,730 years.
Carbon-13 and carbon-14 are thus isotopes of carbon-12.To be thought of as a "person of substance" is a good thing, but to be thought of as a "substance abuser" is not so good.Egyptian chronology can be a challenging subject for biblical creationists.Working with several collaboraters, Libby established the natural occurrence of radiocarbon by detecting its radioactivity in methane from the Baltimore sewer.In contrast, methane made from petroleum products had no measurable radioactivity. Since carbon is fundamental to life, occurring along with hydrogen in all organic compounds, the detection of such an isotope might form the basis for a method to establish the age of ancient materials. Libby, a Professor of Chemistry at the University of Chicago, predicted that a radioactive isotope of carbon, known as carbon-14, would be found to occur in nature.Renfrew (1973) called it 'the radiocarbon revolution' in describing its impact upon the human sciences.Oakley (1979) suggested its development meant an almost complete re-writing of the evolution and cultural emergence of the human species.If you remember the main point of a lesson, you've got the substance.The meaning of the noun substance has evolved over time, yet it has always been related to something sound and solid — from the Latin root substare, which means "to stand firm," to the Middle English definition as an "essential nature." Nowadays, we use the word to define someone who possesses honesty and intelligence, or when we examine a message to find its essence.