by Dr Carl Wieland An attempt to explain this very important method of dating and the way in which, when fully understood, it supports a ‘short’ timescale.
In fact, the whole method is a giant ‘clock’ which seems to put a very young upper limit on the age of the atmosphere.
Living things contain carbon-14 and carbon-12 in a ratio that is the same as in the atmosphere at the time.
When the organism dies, the ratio of carbon-14 to carbon-12 decreases, as carbon-14 decays and is no longer incorporated into the organism.
This dating method works by measuring the ratio of different isotopes of carbon in a sample using a particle accelerator, such as the ANTARES accelerator at ANSTO. The carbon-12 isotope makes up 99% of all carbon on earth, carbon-13 accounts for almost 1%, and carbon-14 is found in trace amounts.
Carbon-12 and carbon-13 are both stable isotopes, but carbon-14 is unstable and is radioactive.
Carbon has unique properties that are essential for life on Earth.
So, we have a “clock” which starts ticking the moment something dies.
Obviously, this works only for things which were once living.
Researchers can find out how long ago something died using radiocarbon dating.
Bones and teeth from animals and humans, as well as artefacts made out of wood, fabric or paper are just some of the objects that can be aged using this process.
by Tas Walker A geologist works out the relative age of a rock by carefully studying where the rock is found in the field.