by Pat Darnell and Abby'rigine Twiggy
Sometime during the glaciation human beings established themselves on the island continent [Australia]. Radiocarbon dating nets this event at a minimum of 45,000 years ago.
What does Radiocarbon dating mean?
Short Answer: Nitrogen-14 is bombarded by cosmic radiation and turns into Carbon-14. In precise half lives the isotope C-14 turns back to N-14... Capic'e?
Longer Answer: "This is how carbon dating works: Carbon is a naturally abundant element found in the atmosphere, in the earth, in the oceans, and in every living creature. C-12 is by far the most common isotope, while only about one in a trillion carbon atoms is C-14. C-14 is produced in the upper atmosphere when nitrogen-14 (N-14) is altered through the effects of cosmic radiation bombardment -- a proton is displaced by a neutron effectively changing the nitrogen atom into a carbon isotope.
The new isotope is called "radiocarbon" because it is radioactive, though it is not dangerous. It is naturally unstable and so it will spontaneously decay back into N-14 after a period of time. It takes about 5,730 years for half of a sample of radiocarbon to decay back into nitrogen. It takes another 5,730 for half of the remainder to decay, and then another 5,730 for half of what's left then to decay and so on. The period of time that it takes for half of a sample to decay is called a 'half-life.' (Source HERE)"
Carbon Dating - is a dating technique predicated upon three things:
- The rate at which the unstable radioactive C-14 isotope decays into the stable non-radioactive N-14 isotope,
- The ratio of C-12 to C-14 found in a given specimen,
- And the ratio C-12 to C-14 found in the atmosphere at the time of the specimen's death.
ASSUMPTIONS about our UNOBSERVABLE PAST:
... [T]he rate of decay (that is, a 5,730 year half-life) has remained constant throughout the unobservable past.
... We must also assume that the ratio of C-12 to C-14 in the atmosphere has remained constant throughout the unobservable past (so we can know what the ratio was at the time of the specimen's death).
... [Radio Carbon Years, RCY], dates derived are often wildly inconsistent. For example, "One part of Dima [a famous baby mammoth discovered in 1977] was 40,000 RCY, another was 26,000 RCY, and 'wood found immediately around the carcass' was 9,000-10,000 RCY." (Walt Brown, In the Beginning, 2001, p. 176)