Accelerator mass spectrometry measures the amount of carbon-14, or radiocarbon, present in a sample, which can be used to calculate its age.Around the world, only about 100 facilities house this equipment.This property makes it especially useful in a process known as “radiocarbon dating”, or carbon dating for short.Radiocarbon enters the biosphere through natural processes like eating and breathing.This process causes a proton to be displaced by a neutron, effectively turning atoms of Nitrogen it into an isotope of carbon – known as”radiocarbon”.It is naturally radioactive and unstable, and will therefore spontaneously decay back into N-14 over a period of time.On the other hand, atmospheric testing of nuclear weapons during the 1950s and 1960s is likely to have increased the Carbon 14 content of the atmosphere.In fact, research has been conducted which suggests that nuclear tests may have doubled the concentration of C-14 in this time, compared to natural production by cosmic rays. If you’d like more info on Carbon Dating, check out NASA’s Virtual Dating: Isochron and Radiocarbon – Geology Labs On-line, and here’s a link to USGS Radiometric Dating Page.
Image Credit: Saverio Bartalini, CNR Faster, cheaper carbon dating Current carbon dating processes require researchers to send a sample to a large facility with an accelerator mass spectrometer and then wait several weeks to get results back.
The physics, chemistry, and biology, behind carbon dating is absolutely fascinating and worth knowing. Earth is constantly being bombarded with cosmic radiation, which are highly energetic, charged particles that originate from stellar disturbances, like solar flares and supernovae.
Some of these particles collide with atmospheric nitrogen and knock off one of its protons.
Here on Earth, Carbon is found in the atmosphere, the soil, the oceans, and in every living creature. C-12, so-named because it has an atomic weight of 12 – is the most common isotope, but it is by no means the only one.
Carbon 14 is another, an isotope of carbon that is produced when Nitrogen (N-14) is bombarded by cosmic radiation.