Radiometric dating is based on the idea that

13 Dec

Luckily, we can measure these fluctuations in samples that are dated by other methods.Tree rings can be counted and their radiocarbon content measured.From these records a “calibration curve” can be built (see figure 2, below).

Australia has two machines dedicated to radiocarbon analysis, and they are out of reach for much of the developing world.Radioactive decay can be used as a “clock” because it is unaffected by physical (e.g. For instance, the amount varies according to how many cosmic rays reach Earth.This is affected by solar activity and the earth’s magnetic field.The second difficulty arises from the extremely low abundance of C, making it incredibly difficult to measure and extremely sensitive to contamination.In the early years of radiocarbon dating a product’s decay was measured, but this required huge samples (e.g. Many labs now use an Accelerator Mass Spectrometer (AMS), a machine that can detect and measure the presence of different isotopes, to count the individual C atoms in a sample.