Now, when I did that, I made a pretty big assumption, and some you all have touched on this in the comments on You Tube on the last video, is how do I know that this estimate I made is based on the assumption that the amount of carbon-14 in the atmosphere would have been roughly constant from when this bone was living to now?
And so the question is, is the amount of carbon-14 in the atmosphere and in the water, and in living plants and animals, is it constant?
But what's interesting is as soon as you die and you're not ingesting anymore plants, or breathing from the atmosphere if you are a plant, or fixing from the atmosphere. Once a plant dies, it's no longer taking in carbon dioxide from the atmosphere and turning it into new tissue. And this carbon-14 does this decay at a specific rate. And you say, hey, that bone has one half the carbon-14 of all the living things that you see right now.
And then you can use that rate to actually determine how long ago that thing must've died. It would be a pretty reasonable estimate to say, well, that thing must be 5,730 years old.
And the way that you can make that calibration, because it turns out it isn't perfectly constant, the way that you can make that calibration, there's two ways, and I have pictures here of both of them, one is to look at tree things. And I'm told this will work up to about 10,000 years. I don't know of any 10,000 year old trees, I don't think anyone does, but maybe there's some remains of old trees.
And so it's kind of a record of the atmosphere up to 10,000 years. Those are the speleothems that are coming from the top of the cave.
If you want to go even further back, you can look at cave deposits, and the fancy word for these cave deposits are speleothems. But the reason why these are useful is these are formed by calcium carbonate, so they have carbon in them, and slowly over, really, tens of thousands of years, the water in the cave deposits that calcium carbonate.
Reviewed by Varnada Karriem-Norwood on August 30, 2012 Sources Dr.
Ruth" Westheimer, Ph D: People have to be sexually literate and since people live longer today, it's particularly important for all of us to educate, to say that you are going to live until 70 or 80 or 90.