Sunday, September 02, 2012 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Sunlight or neutrinos affect the radon gamma decay rate

Seasonal and daytime variations in the gamma decay rate

Several readers have directed my attention to a recent, May 2012 Stanford-Purdue-Israel preprint on the seasonal variations of the gamma decay:

Analysis of Gamma Radiation from a Radon Source: Indications of a Solar Influence
They look at gamma (and alpha) radiation emitted by radium-222, an isotope arising from a decay of uranium-238 through radium-226. What they found was a more striking and accurate confirmation of a 2008 preprint (see TRF 2008) by similar authors.

The money graph looks like this:

Via Wave Watching which offers a useful introduction to the story.

The upper graph shows the number (via the color) of gamma rays emitted by their radon sample at certain dates between 2007 and 2010 on the \(x\)-axis – you see the seasonal dependence – and on the 0-24 hour of the day on the \(y\)-axis – you see the daytime dependence.

To compare, the lower graph shows you the altitude of the Sun in degrees as a function of the same date and time.

The signal and the similarity can't be overlooked. These folks have surely found something. It's a more open question whether the "something" is something completely new or something completely mundane and silly.

A few years ago, similar results were interpreted as the seasonal dependence of the fundamental constants of Nature. I have thought and I still think that such an explanation was a contestant in a contest looking the most implausible, almost paranormal explanation. There isn't any other excuse to think that the fundamental constants should vary, especially not with seasons.

Let me assume that the effect isn't caused by some really mundane systematic effect, something silly that the authors are doing. But this assumption isn't necessarily a proof that the effect proves that there exists new physics. Of course it's at least academically plausible that the properties of nuclei depend on the distance from the Sun or a similar thing.

However, it seems much more plausible that the effect results from the influence of well-known types of particles. In particle, the gamma-ray events they observe don't have to be pure decays (processes with 1 particle in the initial state). They may be collisions, either with some photons or with neutrinos (or, for the sake of completeness, a new particle species) coming from the Sun.

Let me emphasize that if an additional incoming particle plays a role, it's a big mistake to call it the observation of gamma decay! Collisions are not "decay". From a microscopic or fundamental viewpoint, it's also nonsensical to declare the temperature as the driver of the variations: temperature is just a statistical description of energy randomly stored in every degree of freedom but to explain a particular nuclear reaction, we should still be able to see which degree of freedom – probably which field or which particle – showed its muscles.

In his 20-minute May 2012 talk, Peter Sturrock was betting on the neutrinos, too.

The periodicity may have its origin in the solar core, as they suggest. However, if the neutrinos are the culprits, it would seem much more sensible to expect that they're able to ignite some beta-processes, and not gamma-decay.

At any rate, people shouldn't prematurely attribute such observations to some "ghostly" invisible variation in the laws of physics unless they prove that there isn't any extra particle coming from the Sun in the initial state that is behind some (or all) of the processes.

The New York Times has a fun article on Ms Andrea Hlaváčková, an Olympic silver medalist of Pilsen, who just happens to be the daughter of the master brewer of Pilsner Urquell. ;-) It's not just some random appointment by a committee: their dynasty has run the brewery for a century.

Add to Digg this Add to reddit

snail feedback (21) :

reader Pavel said...

It is probably stupid idea, but people activities depends on the Sun altitude. During day light, more people move their radioactive bodies close the experiments, open doors affecting experiment shielding, which may affect the results. Also note the regular decay increase near each end of year. Cannot it be caused by candelas burnt during Christmas?

reader Dilaton said...

I seasonal or daily variation of the fundamental constants seems silly to me too.

If at all they should change abruptly I think ... :-P ;-) :-D

reader Newt Reeno said...

Surely any time the sun is above the horizon the neutrino flux is the same? (Unless the sample in the experiment is arranged asymmetrically, to give it directionality, in which case they shouldn't be so silly.) Surely what you would expect would be a flat constant during the day with an exp-cos-shaped scoop taken out during the night. You could get a seasonal dependence at night as different slices through the Earth blocked varying amounts of flux.

This doesn't look right to me. Why do you think it looks plausible?

reader Luboš Motl said...

I completely agree with your reasons to think it doesn't look plausible but it's also true that I don't know why they get this clear picture.

And I even think that the Earth should be transparent for the neutrinos, almost, so even at nighttime there should be no visible dependence.

reader anna v said...

from Wikpedia :"

Occurrence of radon

On average, there is one atom of radon in 1 x 10^21 molecules of air. Radon can be found in some spring waters and hot springs. The towns of Misasa, Japan, and Bad Kreuznach, Germany boast radium-rich springs which emit radon. Unsurprisingly, Radium Springs, New Mexico does too.

Radon exhausts naturally from the ground, particularly in certain regions, especially but not only regions with granitic soils."

That is about 100 per mole.
Also radon comes up in dangerous amounts through seismic faults and geological cracks, concentrated because of large volume gas collection.

1) how protected is the gamma counter, to environmental radiation ?the counter measures gammas over 50keV, not a specific line, not directionality.

2) environmental gammas could well depend on time of day and year as the ground depends on tides ( about 40cms rise and fall as the moon passes) plus the heating cooling might increase/decrease radioactive gas emissions from the ground of all types.

reader jitter said...

The Moon doesn't really pass;-) but I know what you mean. It also ries and falls when the Moon hides as well as passes.

reader physics junkie said...

Is it plausible that the weak force via neutral current from neutrinos can impart enough force for an alpha decay by the strong force?

reader Curious George said...

Radioactive decay has been usually described as a classic example of a quantum tunnelling. Is there a way to distinguish a "decay" caused by collisions?

reader Gunter said...

The measurement does not show that the decay rate of radon is influenced by sun/temperature/day of year/..
They measured the release of Radon from phosphorite to the air. And this is influenced by temperature, vibrations and other earthly forces.

reader Gene said...

This work is inexcusably sloppy, Lubos, and Sturrock is a very poor scientist. I would say he rightly belongs in the same category as Fleishmann and Pons. Taking a lot of data from an uncontrolled experimental setup is meaningless.

If you look into this experiment carefully and peruse the history of Professor Sturrock you will surely agree with me. I happens that I have had a close working relationship with Stanford’s Applied Physics Department and have found the quality of its work to vary from excellent to absolutely abysmal. This is on the abysmal end. Sturrock is not as flagrantly fraudulent as Fleishmann and Pons but he is a crappy experimentalist.

reader David Nataf said...

The neutrino flux from the Sun should depend on the season's due to the Earth's eccentric orbit, which would cause the neutrino flux to be ~6% higher during northern hemisphere winter.

reader Luboš Motl said...

Sounds great but this source of modulation still contradicts the daytime cyclicity, doesn't it?

reader David Nataf said...

I can't think of any remotely reason for a daily modulation, I misunderstood the topic, sorry.

reader Vlad said...


reader BJ said...

I don't get the talk of neutrinos. In the paper the graphs show that it correlates pretty well with temperature, which is hardly surprising. In a hotter tank more Radon gas gets into the detector. Who thought of this experiment? What's wrong with a nice simple measurement of some solid radioactive source - it would show no such deviation, that's what.

reader dandy said...

I do not believe how a loser who could not secure a proper Faculty position is giving his opinion on matters he understand nothing about. Just grow up. You are nobody who maintains a blog and just bla bla on all issues, hiding behind the smart string people. This does not make you smart. Just a jackass who is pretending to undertand something, although it is clear from what you write that you understand nothing. Go and do something else. You live off commercials because in the academic world you failed. How could you live with yourself? What makes me laugh is that you read some articles, understand nothing and then comments on it.
You are not a physicist. Just someone running a blog. There are much better people who does this job. Just leave it to them. If you have any dignity, you will be better off selling potatoes than maintaining a blog with topic way above your head. Go and quit loser. I know that you are a wimp and do not have the balls to publish this post.

reader steve said...

They measure gamma activity in a separated volume which is connected to the main volume only via a small pinhole --- and expose the whole thing to daily temperature variations. Different parts of the apparatus warm and cool at different rates, you get temperature gradients and thus breathing effects in and out of the pinhole. Of course one expects correlations of gamma counts with temperature then via modulated entry of Rn222 into the small volume. Unless the authors carefully exclude the possibility for these systematic effects which they seem to have chosen not to do.

reader ThePeSla said...


If we assume there is no mundane error... Indeed! And that experimentally, as in your post on the quantum founding fathers suggests for a sounder view, this seems to me part of the mysterious landscape of the new string physics. While I quite imagined in 1963 that neutrinos had some effects like earth quakes the general attitude toward such phantom like particle effects (consider the lumenino theory said 'ludicrous' as metaphysical effects only or any such variation in the rates of nuclear decay as speculative) these new directions in physics just may have to be taken seriously especially in matters of climate science or what may or may not be happening at the center of orbs. Certainly the mechanism of 'neutrino halo' at the sun's core, found recently in theory' for the transfer of heat to other regions of the sun is a new breakthrough and involves perhaps promiscuous effects beyond magnetism as if it is an idea or property of dark matter.


reader Zledge Hammer said...

While traversing the earth, the responsible neutrino fraction is also affecting the radioactive components in the bedrock. This will reduce the effectiveness to influence the night times measurements. Plausible?

reader mnl said...

Absolutely. Besides, detector efficiency usually depends on temperature. This experiment should be done with a calibrated source in a closed environment, constant temperature, a Germanium detector, and voltage stabilization. This is just embarrassing.

reader Carl Brannen said...

The gravitational potential experienced by an object changes with the altitude of the sun. So it seems like a tidal effect. (Uh, I haven't read the article and don't have time to.)