So when you set your newly invented C14 Clock, as Willard Libby did when he developed the method, it has to have a known rate of decay that can be measured against known historical time lapses, e.g..the Birth of Christ, the reign of Julius Caesar, etc.In fact it has all the major problems of a clock that doesn’t tick the way it should. When you invent a new clock you need to know what the time is now, and if you’re setting the clock to run backwards, you need to know how fast it ticks.To do that you have to have a way of knowing what the time was at measured known intervals back into the past.Whilst it is so casually overlooked these days, the first inventor of the Carbon 14 method Willard Libby is definitely on record that the thing surprised him most, was that he didn’t have any written records to compare his Carbon 14 method against that was older than 5,000 years.But he didn’t let that bother him in any way, shape or form.
In the beginning the God created the world very good.
Carbon 14 is a short lived radioactive element with a half-life is only 5,730 years approximately.
So using current technology, you could at the most, use it for objects that only went back 70,000 or so years.
These and other radiation sources are one reason we don’t live to be “as old as Methuselah”.
But while we are alive, what goes in also comes out because you breathe out CO2, which includes some of the radioactive stuff.