changes in decay rate over time

["Karam, Andrew" <Andrew_Karam@URMC.Rochester.edu>]

I just read an interesting paper that suggests radioactive decay rates of
extremely long-lived radioisotopes might have changed over time.  The paper
was written by some astronomers in an attempt to help reconcile some
discrepancies in measurements of the age of the universe.  They suggest
(through mathematical arguments I really don't follow very well) that
isotopes with half-lives similar to the age of the universe (such as Th-232
and U-238) may have decayed more rapidly in the distant past than at
present.  This is interesting and, if true, may affect isotope geologists,
but I don't see offhand how it is of more than academic interest to most of
us.  In addition, I can't see how this can be proved or disproved, which
makes it of questionable utility.  But, interesting reading nonetheless.

For anyone interested, the paper was posted to the LANL physics e-print page
at:

http://xxx.lanl.gov