• Assumptions of Radioactive Dating

    It’s been a long day so I’m going to hit some low hanging fruit here and call it done.

    The first “Hard Question for Evolution” is

    List at least 9 of the false assumptions made with radioactive dating methods.

    There are only two I’m aware of.

    The first is that atoms have always decayed at the same rate.  And this isn’t really an assumption as the decay rates have been tested in the laboratory for a hundred years or so, we have an example of a natural nuclear reactor where we can measure the various products and determine the decay rates (and the fine structure constant), and we can observe the past by looking deep into the past of the universe.

    The other is that the decay products of various atoms are always the same.  This is also actually kind of trivial and easily determined in the lab.

    That’s it.  Let’s see what the Missing Universe Museum thinks are the assumptions of radioactive dating methods.

    • That the atmosphere has had the same (all instead of Carbon 14) concentration in the past as now.  Who knows?  This is a false assumption.
    • That the production of parent isotopes has been constant.  Again, who knows?  This is a false assumption.
    • That the original ratio and amounts of the isotope in the fossil or rock is known.  This is based on current processes and assumes the rate of absorption was the same in the past.  This is a false assumption.
    • That the decay rate is constant.  Many things are known to affect decay rates.  This is a false assumption.
    • That no contamination has occurred.  This is a false assumption.
    • That no daughter (stable) element was originally in the fossil.  This is a false assumption.
    • That the decay rate was determined accurately.  Decay rates are constantly being modified and criticized.  This is a false assumption.
    • That the only loss of the isotope is due to the decay process.  This is a false assumption.

    Wow, that’s a lot of assumptions… but are the really assumptions?  Just looking at this list, I can see that none of these are actually assumptions used by radioactive dating methods and/or they are known issues and compensated for.

    I guess we have to start at the top and work our way down… sigh.  So much for low hanging fruit.  But I’d like you to note something here.  The sigh isn’t for the effort of writing, it’s for the effort of finding all the references.  Something that this particular website has none of.  Indeed, this is a classic Gish Gallop.  Basically, just like all creationists, they are making stuff up and then hoping you won’t check them on it.

    Let’s check.

    1) atmosphere has always had the same amount of C-14

    This is obviously in reference to carbon-14 dating of formerly living tissue.  During an organisms life, it takes in CO2 and uses that carbon to build things or an organism eats an organism that has taken in CO2.

    Some of the carbon atoms in CO2 have the common 6 protons and 6 neutrons.  This is carbon-12.  However, due to some interesting nuclear chemistry (which I’ll go into if requested), there’s another version of carbon (called an isotope) that has 6 protons and 8 neutrons.  Somewhat obviously, this is carbon-14.  Note that if the number of protons change, then the atom is no longer carbon.  It must have 6 protons to be carbon.

    Amazingly (and unlike what is claimed by the creationists), scientists have known about a variety of methods that create carbon-14 and how those methods have varied over time.  Indeed, by doing almost 20 seconds of research on google (type in “variations in C14”, click on Google Scholar) the second link is this article from 1954: Carbon 13 in plants and the relationships between carbon 13 and carbon 14 variations in nature

    So, this issue has been known about for a long time.  Do you honestly think that no one has done anything about it?  Of course not.

    Radiocarbon dating must be calibrated.  How do we calibrate it?  Well, we take a carbon sample from a material of a known age and date that.  Then we compare the two and adjust the radiocarbon date to the known date.  By making thousands (if not millions) of these adjustments we get a very good idea of how old a piece of unknown material can be.

    Yes, this is a range of possible dates.  All radiometric dating systems are  range.  The 2004 calibration set is here.  Basically, the calibration curves are off by no more than 16 years over the historical range (6,000 years or so) and no more than 163 years over the last 20,000 years.  That’s less than 1% if you’re interested in that sort of thing.  The 2009 calibration set extends the ‘well calibrated range’ to 50,000 years using the varves in a Japanese lake.  Varves are cool.  I just like saying ‘varve’.  But this is already almost a thousand words and I’ve only done ONE! response to these clowns.

    Long story short, scientists have always known that variations in C-14 concentration happen.  This is unlike the creationists which think it happened, but can’t be bothered to check.

    Scientists, using rigorous methods have established a process to eliminate this problem by calibrating radiocarbon dating results to items of a known age.  In this way, items of unknown age can be tested and an age determined to a reasonable degree of accuracy.  (Aside, my dad doesn’t know how old I am, he usually misses by about two years, giving him an error of almost 5%.)

    Not only, is this not a ‘false assumption’.  It’s not an assumption at all.  It’s a known issue and been corrected for.

    More tomorrow where we explore the concept of isochron dating and how it neatly destroys most of the rest of these ‘issues’.

    Oh and here’s a link to the Table of Contents for this set of creationist misconceptions.


    Category: CreationismGeologyPhysicsResearchScience


    Article by: Smilodon's Retreat