Things have been totally hectic since I got back from the conference trail - all the usual end-of-year stuff plus heaps of students coming in for advice about their study plans for next year. (Hint for future students - try to do a bit of planning before you come in; it makes the process much easier :) I don't mean picking out every paper that you might want, but having a broad idea of what you are most interested in is a good starting point.)
Did people really live for hundreds of years?" Yes. Pre-Flood, carbon-14 was not present in the vast quantities that pervade our atmosphere today, and cosmogenic C-14 was very rare. During the Flood, the earth's crust, wracked with magnitude-10-to-12 earthquakes and rich in quartz (which generates electricity when deformed), acted as a gigantic fast-breeding nuclear reactor and produced all of the radionuclides (up to uranium and arguably plutonium) known to man today. That included C-14, produced in tremendous quantities through cluster decay. And when C-14 gets into your system, and then decays, it can wreck whatever molecule (including DNA) of which it became a part. So the reason we *don't* live hundreds of years today is that we are all suffering from radiation poisoning (or isotopic substitutional poisoning) and have forgotten what it was like not to be subject to such poisoning.
This is part of a much longer (& equally confused/confusing) series of comments on a post on a US creationist website. PZ & his horde have pretty much taken it apart but I thought I'd share it here as an example both of really really strange thinking & also of the Gish Gallop - a 'debating' technique (& I use the word 'debate' very loosely) where so many totally wrong ideas are bundled out together that the opposing speaker doesn't have a hope of dealing with them all in his or her allotted time. At which point the first speaker can claim 'victory' for their point of view.
Anyway, the writer has a really strange view of how C-14 (a radioactive carbon isotope) is produced and just how much of it there is in the atmosphere. I mean, 'vast quantities' makes it sound like there's heaps! But the proportion of radioactive to non-radioactive carbon in the Earth's atmosphere & oceans is about 1 in 1 trillion, so it's not exactly enough to 'pervade our atmosphere', as the original writer would have it.
C-14 is produced in the upper atmosphere as a result of the bombardment of gases by cosmic rays: periodically a high-energy particle hits a nitrogen atom and generates an atom of C-14. This in turn reacts with oxygen to form CO2, which plants use (just as they do 'normal' CO2) to produce sugars. Thus the C-14 radionuclide enters the food chain. As long as organisms are alive they'll continue to take in C-14 along with 'normal' C-13 & C-12, so the ratio of the different forms of carbon in their bodies remains constant. But once the organism dies, this replenishment stops and the levels of C-14 in its remains begin to drop: the amount of C-14 in dead organic matter is halved every 5730 years as the atoms decay into nitrogen. (This allows scientists to use carbon isotope ratios to date organic material back to about 50,000 years ago.)
However, our author isn't having a bar of this, insisting that such cosmogenic production of C-14 was just about non-existent prior to the Noachian Flood. (Goodness knows where he gets that from; in my younger days I did read the Bible & I don't recall anything there on nuclear physics.) Instead, he claims, magnitude-10 to -12 earthquakes deformed and shattered quartz crystals in the Earth's crust, somehow turning the crust into a 'fast-breeding nuclear reactor' which produced all currently-known radionuclides. Including, of course, C-14. (Magnitude-10 to 12 on what scale? Richter? Mercalli?)
Which would be fine & dandy, I guess, except that while deformed quartz does release electricity, there's no reason why this in turn would turn the earth into a gigantic nuclear reactor. And if it did - the resultant heat would have caused the crust to become molten. The supposed floodwaters would have boiled off & one rather suspects the Ark (& all aboard) would have been incinerated. If, by some chance, it avoided this fate & some waters remained, it would have taken a darn sight longer than the year cited in Genesis for the crust to have solidified, let alone cooled sufficiently for an olive tree to grow...
Just one more contradiction: Genesis has it that Noah lived to be 950. According to our author, the reason modern folks don't live anything like that long is because we are all suffering radiation poisoning from those vast quantities of C-14 produced during the Flood. But... ... ... Noah is supposed to have lived through this massive outpouring of radionuclides & if our author is correct the proportion of C-14 would have been much higher then than it is now. So - how come Noah didn't drop dead on the spot of radiation poisoning?
There is actually a lot more of this stuff in that comments thread. Mammoths (which were apparently tropical beasts, despite all the morphological evidence to the contrary) frozen solid by massive hailstorms accompanying the Flood. (That explains why they never made it onto the Ark, then.) The Himalayas being pushed up by all that earthquake activity & causing the Earth to shift on its axis. It's amazing what you can come up with if you let your imagination run riot and aren't too worried about making stuff up.
But at that point I was saved from having my neurons apoptose by another student knocking on my door :)