Slashdot Mirror
Radioactive Decay Apparently Influenced By the Sun
quax writes "In school you probably learned that the decay rate of radioactive matter is solely determined by the halftime specific to the element. There is no environmental factor that can somehow tweak this process. At least there shouldn't be. Now a second study confirmed previous findings that the decay rate of some elements seems to be under the subtle and mysterious influence of the sun. As of now there is no theoretical explanation for this strange effect buried in the decay rate data."
Step 1) See science I don't agree with
Step 2) Find no logical arguments to shoot it down
Step 3) resort to ridicule and call it a day
The hypothesis is that a yet unknown weak force interaction triggered be the sun's neutrino's is responsible for this.
It'll hardly be the first time that a scientifically observed phenomenon has no current theoretical explanation.
If yours was the way science operates we'd still operate out of caves.
Disclaimer: i am an experimental physicist from another field (with experience in precision measurements).
looking at the arxiv preprint:
Why would one allow a +-3% variation in *absolute* temperature (figure 6). 6% of 300K are 18K (this is huge. My experiment needed to be recalibrated when the temperature changed by 1 degree). This explains also the *huge* fluctuation of the biasing voltage "lead accumulator" completely propotional to the temperature. which brings me to the next point: the paper makes is sound like this voltage was used *without further stabilization* for biasing the electronics. Why any sane experimentalist would accept such fluctuations when cheap and reliable means (controlled heater, 50cent voltage controller) is beyond my comprehension.
That being said, we talk about some difference on the order of 500 counts (per day, see the paper and multiply the numbers...), respectively 25 per hour or 1 per 2 minutes. I am no expert on it, but at such low count rates an exclusion of the influence of cosmic rays would be needed. Sasly the paper also does not show any dark count rate experiment. If they let the same detector run without anything inside and show the data, then we could make some conclusions.
Ideally they shoud have run an identical detector without a sample in close vincinity at the same time and correlate the fluctuations.
> If yours was the way science operates we'd still operate out of caves.
consider if you will where we place our neutrino detectors.
~.~
I'm a peripheral visionary.
It's not exactly the same, but it is the same kookery warmed over. Here's a summary.
Do rates of nuclear decay depend on environmental factors?
There is one environmental effect that has been scientifically well established for a long time. In the process of electron capture, a proton in the nucleus combines with an inner-shell electron to produce a neutron and a neutrino. This effect does depend on the electronic environment, and in particular, the process cannot happen if the atom is completely ionized.
Other claims of environmental effects on decay rates are crank science, often quoted by creationists in their attempts to discredit evolutionary and geological time scales.
He et al. (He 2007) claim to have detected a change in rates of beta decay of as much as 11% when samples are rotated in a centrifuge, and say that the effect varies asymmetrically with clockwise and counterclockwise rotation. He believes that there is a mysterious energy field that has both biological and nuclear effects, and that it relates to circadian rhythms. The nuclear effects were not observed when the experimental conditions were reproduced by Ding et al. [Ding 2009]
Jenkins and Fischbach (2008) claim to have observed effects on alpha decay rates at the 10^-3 level, correlated with an influence from the sun. They proposed that their results could be tested more dramatically by looking for changes in the rate of alpha decay in radioisotope thermoelectric generators aboard space probes. Such an effect turned out not to exist (Cooper 2009). Undeterred by their theory's failure to pass their own proposed test, they have gone on to publish even kookier ideas, such as a neutrino-mediated effect from solar flares, even though solar flares are a surface phenomenon, whereas neutrinos come from the sun's core. An independent study found no such link between flares and decay rates (Parkhomov 2010a). Laboratory experiments[Lindstrom 2010] have also placed limits on the sensitivity of radioactive decay to neutrino flux that rule out a neutrino-mediated effect at a level orders of magnitude less than what would be required in order to explain the variations claimed in [Jenkins 2008]. Despite this, Jenkins and Fischbach continue to speculate about a neutrino effect in [Sturrock 2012]; refusal to deal with contrary evidence is a hallmark of kook science. They admit that variations shown in their 2012 work "may be due in part to environmental influences," but don't seem to want to acknowledge that if the strength of these influences in unknown, they may explain the entire claimed effect, not just part of it.
Jenkins and Fischbach made further claims in 2010 based on experiments done decades ago by other people, so that Jenkins and Fischbach have no first-hand way of investigating possible sources of systematic error. Other attempts to reproduce the result are also plagued by systematic errors of the same size as the claimed effect. For example, an experiment by Parkhomov (2010b) shows a Fourier power spectrum in which a dozen other peaks are nearly as prominent as the claimed yearly variation.
Cardone et al. claim to have observed variations in the rate of alpha decay of thorium induced by 20 kHz ultrasound, and claim that this alpha decay occurs without the emission of gamma rays. Ericsson et al. have pointed out multiple severe problems with Cardone's experiments.
In agreement with theory, high-precision experimental tests show no detectable temperature-dependence in the rates of electron capture[Goodwin 2009] and alpha decay.[Gurevich 2008]
He YuJian et al., Science China 50 (2007) 170.
YouQian Ding et al., Science China 52 (2009) 690.
Jenkins and Fischbach (2008), http://arxiv.org/abs/0808.3283v1, Astropart.Phys.32:42-46,2009
Jenkins and Fischbach (2009), http://arxiv.org/abs/0808.3156, Astropart.Phys.31:407-411,2009
Jenkins and Fischbach (2010), http://arxiv.org/abs/1007.3318
Find free books.