The carbon cycle

[SusanDoris]

My reader was here this morning and we have just passed the part - in ;Living With The Stars' by K and I Schrijver - where it says about the carbon cycle being one which goes in 14 million year cycles, and that the carbon has therefore only been through, um, living things I think, only 35 times.
Now it all sounds as if that is perfectly sensible, but does anyone have any idea how they can tell that the carbon around is 14 million years old and that it runs in 14 million-year cycles?

I do hope there is a chance of a fairly straightforward answer?"

Thank you.

[SteveH]

Radiometric dating, maybe?

[SusanDoris]

Radiometric dating, maybe?

I don't know, but how could they tell that it was the same carbon lasting all that length of time?

[ippy]

My reader was here this morning and we have just passed the part - in ;Living With The Stars' by K and I Schrijver - where it says about the carbon cycle being one which goes in 14 million year cycles, and that the carbon has therefore only been through, um, living things I think, only 35 times.
Now it all sounds as if that is perfectly sensible, but does anyone have any idea how they can tell that the carbon around is 14 million years old and that it runs in 14 million-year cycles?

I do hope there is a chance of a fairly straightforward answer?"

Thank you.

Our Jim Alkali's very good at explaining this sort of thing, there's a lot of his stuff on 'YouTube', You might find your answer there; I have heard this sort of thing explained and I find it understandable when explained but if you ask me about the explanation even only about five minutes after I've heard it, there's not much of it left for me to pass on, all I can say is how they do carbon dating makes sense to me for those few brief moments it fleetingly rests in my brain.

Regards ippy