Sorry Creationists, Radiometric Dating Still Works

About a month ago, there was a story about scientists from Purdue University claiming that they have measured changes in decay rates of certain isotopes. The changes, they claimed, corresponded to the orbit of the Earth around the sun, and the rotation of the core of the sun.

They hypothesized that it could be neutrinos emitted from the sun’s core interacting with the radioactive substances, causing a change in their decay rate.

I’ve written a post previously on radiometric dating. The technique is used to estimate the age of archaeological samples and rocks. It is used to determine the age of skeletons, fossils, and rocks. The geologic history of the Earth is based on these techniques, and it is how we know how old the Earth is.

So any inconsistency with the decay rate of an isotope we use for these dating techniques would be interesting indeed. But, perhaps not surprisingly, I am skeptical.

One of the scientists was quoted as saying,

What we’re suggesting is that something that can’t interact with anything is changing something that can’t be changed.

Very aptly put. Neutrinos are particles emitted by the sun and very nearly massless. Billions of them pass through you every second and do not interact with the atoms and molecules in your body.

So the idea that they may, somehow, be able to change the decay rates of radioactive isotopes is quite an extraordinary claim, and it therefore requires extraordinary evidence.

This article states that

The Purdue team has ruled out the possibility of experimental error or an environmental influence on the detection systems.

That claim, any scientist will tell you, is at best bold, and at worst laughable. Being able to conclusively eliminate all environmental factors is very difficult indeed. Particularly in the work of these scientists, who used data and labs in several different locations.

That the orbit of the Earth could have any measurable effect on these isotopes is very unlikely. Consider this. Some have claimed that because the Earth’s orbit is elliptical,  the Earth is sometimes closer to the sun than at another part of the year. This could increase the flux of neutrinos and possibly account for changing decay rates of isotopes.

The Difference in Earth-Sun distance between aphelion and perihelion is about 4 million km (diagram is not to scale). Picture Credit: NASA

This seems unlikely, since the flux of neutrinos changes by only about 5% though the course of the year (I did that math myself, feel free to check it if you wish).

In addition, their study looked at decay rates of several different isotopes, and used data from a variety of labs. This is not a controlled experiment, but we can’t discount the findings simply because of that. However, they also found that the change of decay rate they measured was not the same for all of the isotopes they studied. So this could mean that the neutrinos are interacting differently with each isotope, or it could mean they are simply getting anomalous readings.

Other scientists are starting to respond as well. A study was recently published which measured the decay rate of Gold-198 over several weeks. The researchers set up the experiment so that one sample got many times more neutrinos bombarding it than the control sample. No detectable change in radioactive decay was measured.

So the question is still largely unsettled. Oh but wait. Even though Creationists and Young Earth Theorists love to take studies like this and spin them to say that the Earth may not be as old as we thought, consider this…

The changes the Purdue researchers measured were fractions of a percent. They would not have any significant effect on the dating of any geological or archaeological sample. So even if their numbers are right (which I don’t think they are) they wouldn’t affect our measurement of the age of the Earth.

But this is what science is all about. Making a discovery and then trying to prove it to the rest of the world. Whether the neutrino theory turns out to be true or not, it is a classic example of why science works.