Re: Radioactive decay and long-term preservation

Spike Jones (
Thu, 21 Oct 1999 21:52:19 -0700

> >[spike encourages] the laughter Jeff. {8^D But I dont get it. Are you
> saying
> >there is carbon 14 in coal? I meant, wood has carbon 14 to start with,
> then
> >over the eons it takes to form coal, yer 14 goes away, half every 6k years.
> Jeff Davis wrote: Right you are spike. My mistake in thinking you meant it
> was *all* gone,
> as in none, zero, zippo, nada. The not-much-more-than-infinitesimal bit
> that's left is what is used for carbon 14 dating.

No problem Jeff. Let the laughter continue. {8^D

Actually I really did mean *all* the carbon14 is gone out of the coal. Every last atom of it. Imagine a forest of reaaally big trees, verrry closely packed.

5 meter diameter at the base, in a grid on 10 meter centers, 100 meters tall. I know real trees arent so big and so close, but these assumptions make the numbers come out easy. {8-] Each square kilometer has 1E4 trees, and each tree has a mass of about 600 tons, so 6E6 tons per km^2.

John Grigg is from Alaska, so lets imagine that biiig-assed state covered with this superforest. I think I recall Alaska has 1.6 million square kilometers (is that about right John?) so the Alaskan superforest would have about 10^13 tons of trees. Trees arent *all* carbon, (some of it is hydrogen, some oxygen etc) but lets ignore that for conservative estimates and clean numbers. One atom of each million carbon atoms is C14, so we get about 10 million tons of carbon 14, or 1E13 grams and at 14 grams per mole and 6E23 atoms per mole, we have about 4E35 atoms C14 in the Alaskan superforest. So far so good?

Nowthen, assume some really big volcano buries the entire Alaskan superforest so that no carbon is lost to oxidation and no new carbon sources leak in. 4E35 is about 2^119, so after 119 halflives we would expect to have exactly one atom of carbon 14 left. Carbon has a halflife of about 5700 years if memory serves correctly, and so after less than 700,000 years, we should be down to one atom of C14, and 6k years after that time its a coin toss if you have that one left, 12k yrs later, 25% chance, etc.

Even if one assumes an earth-sized planet, all land, no oceans, completely covered with the superforest, the time to decay every last C14 atom is *still* less than 3/4 of a million years, perhaps long enough to start converting the peat bogs to bituminous, but not long enough to form a good hard glassy anthracite coal. Conclusion: Anthracite has no C14 atoms in it at all, not one.

So: dig up anthracite coal, burn it, exhaust the resulting CO2 into an airtight greenhouse, grow plants that appear very old to the people at the C14 dating service. Or mix it with modern air to make textiles that C14-date to any arbitrary age: grow flax in about 1/3 coal exhaust, grow some flax, make a new Shroud of Turin, only this time make it outta cloth that radiocarbon dates to about 1970 yrs old. Then when the faithful start worshipping the thing, reveal your hand. Kind of a Piltdown Man's revenge. {8^D

Then leave town.


Or use it to impress the ladies down at the C14 place: grow long hair and beard, dress up in a Fred Flinstone outfit and a big gnarly club, tell them you are Grog and you were caught in a sudden blizzard while trying to slay a wooly mammoth. You just melted and everything was different, etc, and see if you can convince them to C14 date your big gnarly club.

Or, market the carbon14-free food to rich people as a possible life extender, protection against radioactive decay of their DNA.

Or market it to cryonics fans as a way to help protect them from decay during the cold sleep.

Or, think about this: when we make nanomachines, if we make them out of carbon, those nanomachines that encorporate a C14 atom might appear to suddenly explode without warning. So make them out of anthacite coal.

Jeff, thanks for starting such a wonderfully thought-provoking thread! Did you start it? spike