As often happens we get visitors to the Beagle that like to try out their knowledge on us "sciencey" types. A gentleman was looking at Polly in our front window this afternoon. When I told him it was a nearly complete fossil of an adult Psittacosaurus that was 125 million years old, he replied, "you don't really believe that do you?" I allowed as to the fact that I neither discovered the fossil nor dated the fossil itself, but was confident that it had been properly dated most likely based on several factors. He than said, "how do you explain the fact that granite contains polonium, since polonium has a half-life of only a few seconds?" I replied that I didn't have to explain it, but I did tell him that polonium has isotopes that range in weight from 194 to 218 and the natural isotopes have half-lives ranging from 0.145 seconds to 102 years.
After he left I did some data mining on-line and found a short article that is spot on point:
"Creationist Robert Gentry has argued that ring-shaped discoloration (halos) in primordial granite rocks are the result of damage from alpha-particle emission by radioactive isotopes of the element polonium (Po). Since radiogenic polonium has a very short half-life (usually measured in fractions of a second), Gentry argues that, if granite takes thousands to millions of years to form as mainstream geology believes, any polonium originally present would have decayed away long before the granite could have formed and could not have produced these (halos). Therefore, he feels that their existence is evidence for an instantaneous and recent creation of these granite rocks, and by extension the Earth. The following articles point out the flaws in Gentry's argument.
"Polonium Haloes (sic)" Refuted
Professional geologist Tom Bailleul takes a second look at Gentry's claimed polonium (halos), arguing that there is no good evidence they are the result of polonium decay as opposed to any other radioactive isotope, or even that they are caused by radioactivity at all. Gentry is taken to task for selective use of evidence, faulty experiment design, mistakes in geology and physics, and unscientific principles of investigation and argument style.
Evolution's Tiny Violences: The Po-Halo Mystery
Amateur scientist John Brawley investigated Gentry's claims directly by studying local rock samples, and concluded that there is no good evidence that these "polonium" (halos are actually produced by polonium at all, as opposed to longer-lived radionuclides such as radon or uranium."
This was taken from: http://www.talkorigins.org/faqs/po-halos/.
1 comment:
This is one that I've run into before - the Counter-Creationism Handbook (Isaak, 2007), which is basically a print version of the talkorigins archive, covers it (pp. 198-99), and it's a pretty simple refutation.
The trouble is, unless you have this book to hand at all times (and I'm thinking of just carrying it with me) it's like what was used (by better debaters than me) in high school forensics. There were files of things called "squirrel killers" - these were the refutations for any crackpot argument that the other team might try to bring up on the topic being debated, in the hopes of catching someone unprepared. Crackpot arguments, obviously, equal squirrels.
At the end of the day, this is the same old codswallop of not reading beyond the part in some cretinist tract that tells you what you wanted to hear. Then, having presented your "sciencey" sounding argument, you expect to be lauded for cleverness while the whole of the structure of geochemical dating come crashing down and you swan smugly off on your merry way.
Unfortunately, your argument just ends up as a squirrel. A dead one.
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