I was hoping you would join in, you're a huge numbers guy, so your input is most appreciated.

Couple things to note: The assumptions of starting parameters and constancies over time is only one of the problems. Even if you had a million numbers that all did the same pattern (such as maybe 1000 years ago the half-life rate tripled and quadrupled for a few years), then you would expect a constant across all things, and not be able to determine a flaw in the dating from the results, because everything would be +/- that amount (that was that age or older). Potentially flawed formulas or assumptions always resulted in the same potentially flawed answers, whether it's 1 test, or a million.

But yes, the process by which these assessments are made is by the predetermined age, which is used to benchmark the end results, and discard anomalous results. I cannot definitively state that at this very second in time, that is how they are done (they may change their process at any moment, which is a great thing about science!), but as of college courses being taught regarding this very subject, this is part of the process by which samples are submitted, tested, and results returned. This is especially true for fossils, which the predetermined date is often determined by the rock layer it was found in. This is a problem, because the rock layers were defined by the fossils that occurred in them, creating a sort of circular logic. This is not always the case, of course, but does serve as but one example. Incidentally, afaik, no dating techniques work accurately on the rock layers themselves. Here is a quick link I found on the subject, but I encourage you to do your own studies on it further, and not implicitly trust internet articles at face value: http://wiki.answers.com/Q/How_do_you_determine_the_age_of_a_sedimentary_rock_or_a_fossil_contained_within_it -- This clearly explains the circular logic I am referring to.

Again, even so, there are still the assumptions about the starting parameters, and what occurred between that period and now that may or may not have altered or skewed the test results. One would expect that if there were such things occurring in nature, they would have a linear effect on the entire sample, and likely all samples that exist at the given time, making discovering such shifts in the constants exceedingly difficult to discovery without direct observation and measurement of them occurring during our lifetimes.

The law of large numbers is very applicable, considering our sample sizes are billions of atoms.
And if you've got things that alter half lives, hit me with it. Haven't heard about anything changing a half-life.

The half-life of lighter elements, like beryllium, have been demonstrated to be changed by chemical bonds depending on the proximity of the electrons to the nucleus, as well as some other environmental effects which change the structure of the atom (the 1s and 2s electrons, which are measured in the decay rate). Rhenium-187 half-life is changed even more dramatically when it is fully ionised (bare nuclei). There have been measurements of changes to some elements from other effects, like solar flares, and such as well, but that research is not fully conclusive.

It's interesting reading, if you're into that level of scientific-masochism. No, but seriously, it's pretty cool stuff.

Curious, where'd you read about it?
I'd be interested in knowing what the other environmental effects are, since none of these seem to apply to heavy metals, which would not have inner electrons effected strongly by bond shapes (so much shielding).
Also, I'd be fascinated to hear where in nature you can find Rhenium-187 stripped to its nucleus. 75 electrons are awfully hard to remove.

I remember reading part of this in Science magazine, fairly recently within the last few years. The other ones were in other articles, but might be longer ago (non-internet, the rhenium-187 one), I'd have to do some digging, but hopefully you can find them by some google searches, I'm fairly certain the material is archived on the internet from most of these publications (at least the Science ones)

I would like to say that i wasnt starting a debate. but you can say i have or havent looks as if theres some really good points in this thread.

nazis Are? Better than what?

Yes jews always got ran over each life xD
oh wait jews=.......what again?

This post was edited by Ldr on May 24 2011 07:09pm

That didnt make any sense?

I guess what njaguar is saying in my head is belive what you belive