Carbon dating, also known as radiocarbon dating, is a scientific method used to determine the age of ancient organic materials (anything that came from a dead plant or animal). Developed in the late 1940s by American chemist Willard Libby, this technique has revolutionised fields such as archaeology, paleontology and geology. Libby’s pioneering work earned him the 1960 Nobel Prize in Chemistry, and today, carbon dating remains an essential tool for understanding historical and prehistoric events.
Carbon dating is based on the radioactive decay of carbon-14 (C-14), a rare isotope of carbon. While living organisms continuously absorb carbon from their environment, including a small proportion of C-14, this process stops when the organism dies. Over time, the unstable C-14 atoms decay into nitrogen-14 at a predictable rate, with a half-life of approximately 5,730 years. By measuring the remaining C-14 in a sample and comparing it to the expected levels in the atmosphere, scientists can estimate when the organism was last alive.
Carbon dating is widely used in various scientific fields. Archaeologists rely on it to determine the age of artifacts, ancient tools and human remains, while geologists use it to date geological events such as volcanic eruptions. Paleontologists apply carbon dating to analyse fossils, helping to piece together Earth's biological history. Additionally, climate scientists use it to study past atmospheric conditions by examining ice cores and tree rings.
The field of carbon dating is not without controversy. In a 2018 paper published in the Proceedings of the National Academy of Sciences, a team led by archaeologist Stuart Manning identified variations in the carbon 14 cycle at certain periods of time throwing off timelines by as much as 20 years, due to climatic differences between the northern and southern hemispheres. Even so, 20 year is not that long when looking at some of these time frames.
Here are some examples of where carbon dating has enlightened us:
One of the most famous applications of carbon dating was the analysis of the Dead Sea Scrolls, ancient Jewish texts discovered in the 1940s. Scientists used carbon dating to confirm that the scrolls date back to around 150 BCE to 70 CE, providing crucial historical context for religious and cultural studies.
In 1991, hikers in the Alps discovered a remarkably well-preserved mummified body. Carbon dating revealed that Ötzi, as he came to be known, lived around 5,300 years ago during the Copper Age. His remains have provided invaluable insights into prehistoric human life, diet and health.
While Stonehenge’s iconic stones cannot be directly dated using this method, scientists have used carbon dating on buried wooden posts and organic materials found at the site. These findings helped establish that the monument was constructed in several stages over a period of 1,500 years, beginning around 3000 BCE.
The Shroud of Turin, a venerated religious relic, was carbon-dated in 1988. The results suggested the linen fabric originated between 1260 and 1390 CE, casting doubt on claims that it belonged to Jesus Christ. However, controversy remains over the accuracy of this dating due to potential contamination.
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References
wikipedia.org/wiki/Radiocarbon_dating
wired.com/2010/05/0518stonehenge-carbon-14-dating/
pnas.org/doi/10.1073/pnas.1719420115
novoscriptorium.com/2019/08/14/what-have-we-recently-learned-about-stonehenge/
Images
1. Dead Sea scrolls
2. Willard Libby, winner of 1960 Nobel Prize in Chemistry, in the laboratory
3. Carbon-14
4. Carbon-14 process. Credit: answersingenesis.org
5. A replica of Ötzi's copper axe
6. Secondo Pia's 1898 negative of the image on the Shroud of Turin. Credit: Musée de l'Élysée, Lausanne
7. Stonehenge
8. Measuring 14C using an accelerator mass spectrometer at Lawrence Livermore National Laboratory
9. Nicole Misarti and Matthew Wooller prepare a wooly mammoth tooth sample for radiocarbon dating. Photo credit: Audrey Rowe via uaf.edu
