"Going back to take another look at the decay data from the Brookhaven lab, the researchers found a recurring pattern of 33 days. It was a bit of a surprise, given that most solar observations show a pattern of about 28 days – the rotation rate of the surface of the sun.
The explanation? The core of the sun – where nuclear reactions produce neutrinos – apparently spins more slowly than the surface we see."
This sounds a lot like they are trying to fit an explanation to their data. Surely they would need some sort of secondary evidence for this kind of conclusion -- especially considering the topic at hand is brand new and unexplored.
The sun is a big ball of plasma, not a solid object. It's got currents and layers doing all sorts of interesting things--and what you see on the surface doesn't necessarily tell you what's going on below.
[edit]: I don't know much about stellar physics. See reply.
I am not aware of any model of star formation that might leave the outside of a star rotating faster than the inside. And helioseismology suggests that our Sun's core rotates 3-5x faster than the equator. http://www.sciencemag.org/cgi/content/abstract/316/5831/1591
I'll have to defer to your expertise! I've got very little experience with stars. Do you suppose that if the core is rotating faster than the surface, a slower periodicity could be obtained by a beating interaction between the different angular frequencies?
Actually, we can already measure stellar neutrinos... I wonder if we've already observed this hypothetical 33 day period.
The point about the rotation rate of the solar core is merely a corollary from their hypothesis. The hypothesis is that the variation in the radioactive decay rate is caused by solar neutrinos. The experimental evidence supports most aspects of this hypothesis, except that they were expecting a somewhat faster period. Given the facts that the surface of the sun rotates once every 28 days and that our period is caused by the solar core, whose exact rotation rate is unknown, it is not unreasonable to suppose this is the first evidence to show that the rotation rate of the core of the sun is somewhat lower than that of the surface. A resulting period of 1 hour or one year would have been reason to suspect the hypothesis was wrong. As it stands, they have every reason to suppose their hypothesis is right.
"It's exactly the sort of thing RATE (http://www.icr.org/rate/) has been talking about. The main point of the RATE project is to discredit the radioisotope dating methods. Sometimes they just send samples from the same rock formation to different labs and get different results. But they also spend a lot of time finding reasons that radioisotope decay rates might change over time.
This is all from what I remember from a conversation I had with someone involved with the project about 10 years ago. They got a lot of funding and a lot of interest back in the late 90's when they were just starting. I thought some of their research was interesting, but there was so much propaganda mixed in that it turned my stomach, so I stopped following it."
Say what? Atomic clocks are based on hyperfine transitions--electrons jumping between energy levels. That's an entirely different process than beta decay, which does involve neutrinos.
(The proposal is that neutrinos emitted from the sun are responsible for small changes in radioactive decay rates.)