Krugman: Views Differ on Age of Planet

[Dirkadirkastan]

How is that aquarium experiment relevant to anything? Since when did rain pour from UNDER the earth and violently shake the planet?? It sounds much more likely that someone read a storybook and is now desperately trying to validate it with a false analogy.

As for the radioactive dating... the "average life" refers to taking the average over the whole system. It does NOT imply that the actual life of every particle lasted at or even near that duration. If half of the atoms have decayed in 5000 years, then that's really going to skew the overall average lifespan toward a small number. By comparison, very few atoms survive 100 half-lives, and thus their long lifespan ultimately doesn't affect the average lifespan value that much. But some do last that long... after all, that's the whole idea behind the half-life. Half of the atoms decay and half remain after each half-life, so there will always be a few hanging around.