Dating techniques based on radioactive decay
Radiometric dating techniques indicate that the Earth is thousands of times older than that--approximately four and a half billion years old.Many Christians accept this and interpret the Genesis account in less scientifically literal ways.Many Christians have been led to distrust radiometric dating and are completely unaware of the great number of laboratory measurements that have shown these methods to be consistent.Many are also unaware that Bible-believing Christians are among those actively involved in radiometric dating. Wiens has a Ph D in Physics, with a minor in Geology.
There are over forty such techniques, each using a different radioactive element or a different way of measuring them.
He was employed at Caltech's Division of Geological & Planetary Sciences at the time of writing the first edition.
He is presently employed in the Space & Atmospheric Sciences Group at the Los Alamos National Laboratory.
You cannot predict exactly when any one particular grain will get to the bottom, but you can predict from one time to the next how long the whole pile of sand takes to fall.
Once all of the sand has fallen out of the top, the hourglass will no longer keep time unless it is turned over again.