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carbon dating...

A typical rock is made up of many minerals. Above a temperature that depends on both the mineral and the decay product, decay products can migrate out of the mineral as they form.

So for instance, if you have a rock with mica and K-feldspar, and examine it in the K-Ar system, you might expect that the chronometer in the K-feldspar has withstood heating events that reset the chronometer in the mica. The rock got hot enough for argon to diffuse out of mica but not hot enough for argon to diffuse out of feldspar. If one's dealing with an igneous rock one looks for several minerals that record the same age to date its formation - this is the essence of the isochron method of dating.

The age of a rock is a loose concept anyway. You examine the rock and see what processes have affected it. Then you examine the isotope systems of the various minerals and interpret the data in the light of what you learnt about its processing.

There are effects that change decay rates, but they aren't encountered in terrestrial rock samples. For instance, stars are hot enough to excite nuclei to metastable states that have different lifetimes against beta decay. Of course, these temperatures are much higher than any rock can withstand and in isotope dating decay that took place before the rock formed has no effect. Another example: totally ionised nuclei do not undergo electron capture reactions (such as 40K decay to 40Ar).

This emphasises the problem I mentioned above. The conditions that speed up beta decay don't speed up electron capture or alpha decay. Geochronology uses all 3 sorts of decay, so how can we get consistent ages if decay rates altered?
 
Correa Neto,
Nice links. Thanks

What is Ma an abbreviation for? I assume it meant millions of years.

If I was arguing for the young earth idea, I think I would just hypothesize that the earth was created with about the mix of isotopes present in the rocks today and not that there had to be changes in the decay rates.

Of course if one looks at the totality of evidence from things like deep sea spreading, paleomagnetism and erosion one really has to strain to make this data consistent with the concept of a 6,000 year old earth.
 
You´re wellcome! And right on the spot.

Ky = Ka = thousand years
My = Ma = million years
Gy = Ga = billion years

The isotope mix idea would not work also, since the isotope rates are very variable, indicating ages spanning from 4.1 to the present day (note- there are the "magic numbers"- ages that are quite common around the world, generated by global tectonic events- please do not confuse this with the catastrophe geology, which is a catastrophic approach- sorry, I could not resist). Sure, a creationist could just say that this is another example of how God´s (or the Devil´s) hands (does God has hands?) tailored our planet.
 
Correa Neto,
Not to dwell too long on what seems like a pretty silly idea, but what I meant was that at the time earth was created the rocks were created just about how they are today except that they had about 6000 years less radioactive decay.

If one assumes a supernatural entity that created everything about 6000 years ago, why is it any less plausible to assume the entity just created everything about the way it is today including the signs of long term erosion, mountain upheavals, sea floor spreading, fossils, etc. than any other theory about what this entity did?

The point is debunking a supernatural being of unlimited and unknown power with physical evidence can never succeed fully when one just needs to hypothesize a new set of previously unknown powers for the entity.
 
daver said:


My understanding is that the decay products can vacate the premises if the substance isn't solid.
Click to expand...

This is correct. The rate of decay DOES NOT CHANGE. The decay products can boogie if the mechanical state of the material allows it.
 
Not sure this is the right place to ask this question, but do the young earth folks deal with age of the universe, hubble constant type issues? Is the idea that God created all the stars including there various motions 6000 years ago also?
 
davefoc said:
Not sure this is the right place to ask this question, but do the young earth folks deal with age of the universe, hubble constant type issues? Is the idea that God created all the stars including there various motions 6000 years ago also?
Click to expand...

I've seen YECs use the apparent insufficiency of matter as evidence of a young cosmos--God created the galaxies 6000 years ago; this is apparent because the observed motion of the stars in the galaxies are inconsistent with the observed mass distribution. I expect they will use the apparent increase in the rate of expansion of the universe in the same manner.
 
davefoc said:

Not to dwell too long on what seems like a pretty silly idea, but what I meant was that at the time earth was created the rocks were created just about how they are today except that they had about 6000 years less radioactive decay.

If one assumes a supernatural entity that created everything about 6000 years ago, why is it any less plausible to assume the entity just created everything about the way it is today including the signs of long term erosion, mountain upheavals, sea floor spreading, fossils, etc. than any other theory about what this entity did?
Click to expand...

Actually, this argument is used a lot by young earth creationists. However, this argument is not a scientific one, since by the way it is constructed there is absolutely no way to test it, or to falsify it.

So if one was seeking to refute this argument, one would have to use philosophical or theological arguments, not scientific ones. Ockham's razor is one possibility, since the above argument assumes an additional unproven entity, when compared to the scientific explanation that simply takes the evidence of an old Earth at face value.

Also, remember that creationists are basing their claim of a 6000 year old universe on the Bible, which they believe was basically "written" by God and therefore inerrant. However, if God also created the Universe, wouldn't one expect this to be inerrant too? So why believe every word that the Bible says, while disbelieving what actually studying the Universe tells us? Why assume that God basically "tricked" us by making the Universe look older than it is, while not considering the possibilty that God "tricked" us when writing the Book of Genesis? Aren't the two equally as likely, or unlikely? Besides, personally I don't understand the mindset that fixates on what seems like a pretty peripheral point in one's faith (i.e. whether the Universe is 6000 years old or not) while not worrying about the fact that God could be pulling a huge hoax on humanity.

Finally, if a supernatural entity could do this, why, apart from the Bible, fix on an age of 6000 years? Why not believe that the universe was created 200,000 years ago, or 200 billion years ago, or for that matter, last Wednesday? Surely a sufficiently powerful supernatural entity could plant memories in our brains, fake historical artifacts, write all of the world's literature, from the Epic of Gilgamesh to the latest Harry Potter. And yes, even the Bible. So why not believe that the Universe was created last Wednesday?

And that's exactly why we have to take the evidence at face value. Down any other road lies madness...
 
Brian the Snail,
I think you are really talking to the choir here. I doubt that there are any young earther's out there that are reading this thread.

You summarized pretty well about how I feel about the issue.
 
davefoc said:
Brian the Snail,
I think you are really talking to the choir here. I doubt that there are any young earther's out there that are reading this thread.
Click to expand...

Yes, you're probably right. I guess I just started to respond to your point and got carried away. Sorry if it sounded like I was lecturing.

Regarding your other question about how creationists deal with the age of the universe, the Talk.origins website might be useful for looking up some of their arguments:
http://www.talkorigins.org/origins/faqs-youngearth.html
 
Brian the Snail,
Didn't mean to say I didn't appreciate your post. It was nice to see a well written summary of ideas that I had mused about myself. I actually started a post where I expanded on your thoughts about the strangeness of using the bible for this kind of thing, but it got longwinded and off topic so I deleted it.

Thanks for the link.
 
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