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Nuclear Decay May Vary With Earth-Sun Distance
KentuckyFC writes "We've long thought that nuclear decay rates are constant regardless of ambient conditions (except in a few special cases where beta decay can be influenced by powerful electric fields). So that makes it hard to explain two puzzling experiments from the 1980s that found periodic variations over many years in the decay rates of silicon-32 and radium-226. Now a new analysis of the raw data says that changes in the decay rate are synchronized with each other and with Earth's distance from the sun. The physicists behind this work offer two theories to explain why this might be happening (abstract). First, some theorists think the sun produces a field that changes the value of the fine structure constant on Earth as its distance from the sun varies. That would certainly affect the rate of nuclear decay. Another idea is that the effect is caused by some kind of interaction with the neutrino flux from the sun's interior which also varies with distance. Take your pick. What makes the whole story even more intriguing is that for years physicists have disagreed over the decay rates of several isotopes such as titanium-44, silicon-32, and cesium-137. Perhaps they took their data at different times of the year?"
Does this have any ramifications for carbon dating?
There is a war going on for your mind.
First, some theorists think the sun produces a field that changes the value of the fine structure constant on Earth as its distance from the sun varies. That would certainly affect the rate of nuclear decay. Another idea is that the effect is caused by some kind of interaction with the neutrino flux from the sun's interior which also varies with distance. Take your pick.
You left out the best part of the paper, where they propose how to test these theories:
These conclusions can be tested in a number of ways. In addition to repeating long-term decay measurements on Earth, measurements on radioactive samples carried aboard spacecraft to other planets would be very useful since the sample-Sun distance would then vary over a much wider range. The neutrino flux hypothesis might also be tested using samples placed in the neutrino flux produced by nuclear reactors.
Sounds like we could test the latter relatively easily.
Also, Jeeeeeeeeeeeeeeeeeere H. Jenkins!!!
My work here is dung.
Could this be the cause of the Pioneer Anomaly ?
If this turns out to be true, and not a product of some experimental error, it sounds like it could lead to some very interesting new theories. If it's due to neutrino flux, that indicates neutrinos interact much more strongly than previously thought.
In their theory, the Sun produces a scalar field which would modulate the terrestrial value of the electromagnetic fine structure constant EM.
The fine structure constant (about 1/137) has been measured to a whopping 10 significant digits, one of the most precisely measure physical constants. If there is a seasonal variation enough to influence decay rates by .1%, wouldn't this show up in different experiments measuring the fine structure constant?
This graph seems to indicate that the correlation is between the decay rate and the radius of Earth's orbit squared, not just r.
Could it be that the correlation between decay rates is with Earth's orbital velocity, acceleration, or dTheta/dT (rate of change of the Earth/Sun vector due to Earth's elliptical orbit)?
Additionally, there seems to be a phase shift between peak r^2 and peak decay rates with the decay rate peak seemingly correlated with our peak acceleration toward the sun.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
This is a good example of how many holes there might be in our theories about the universe. We have been making measurements for a few 1000 years in one solar system (mostly just on one planet) and things that we don't see changing, like radioactive decay rates, we consider constant. It's exciting to think how much more there may still be to discover.
This makes me wonder about the http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generatorpower sources on board the Voyager spacecraft, as they are based on the decay of radioactive material. Has our earth-centric understanding of the universe led us to build probes designed to push the boundaries of the solar system and continue into interstellar space, that will gradually lose power the further they get from the sun?
Whoops.
If fate makes you a motorcycle, you become a motorcycle.
As someone who made the equipment that the scientist probably used to do the counting, I have one possible explanation. Most Multichannel Analyzers (MCAs) of the time used a line clock to determine the time. They assume that the power company delivered 60Hz power (or 50 Hz in Europe), This frequency was almost never precise but varied by .1 to .2% (one plant where I measured the frequency put out 58.8Hz for example, a real mess for us) from time to time. A systemic variation due to power loads (heating in winter/ AC in summer) could easily bias the power frequency by about the right amount with the right periodicity.
The universe might well be safe.
TFA's frame of reference is the Earth's orbit about the Sun, and reports a small but significant correlation between aphelion - perihelion and decay rates of some radioactive nuclides. TFA suggests that the 4% change between Earth's closest approach to the Sun and its most distant point is a possible cause for the change in decay rates.
When the frame of reference is expanded to galactic distances, we find that Earth's aphelion point is coincidentally very close to a line drawn from the Sun to the center of the galactic core. So it could also be that some shielding or suppressive effect of the Sun's local environment is reducing decay rates when the Earth is behind the Sun relative to the galactic core.
Proposed hypothesis: the changes in radioactive decay rates are related in an unknown fashion to the annual changes in the geometry of the Earth - Sun - galactic core.
This could probably be ruled out with a couple of tests of the existing data:
Aphelion occurs on Jan 4, while Earth's fullest exposure to any presumed galactic core influence occurs on Dec 17. Does the data suggest that increased activity centers around aphelion, or 18 days earlier?
If TFA's heliocentric model is correct, the change in rates of decay from month to month will be a smooth sinusoidal curve over the course of the year. But if the galactic core is involved, the changes in rates of decay will depart from this since the ecliptic does not parallel the galactic plane, and the degree of the Earth's "exposure" to galactic core will vary in a more complex way. Does the data support either of these conjectures?
I'm not going to cite my references here: they would be a distraction. Key words for google: aphelion, perihelion, solstice, galactic core, "plane of the ecliptic", "galactic plane". Um, a quick review of high school trigonometry might be useful, too.
Kudos to all the researchers and lab assistants who contributed to this work. It sounds like years of seemingly mindless drudge data collection went into this database. Yet the results are stunning: something Out There is affecting "constants" that we thought were intrinsic and immutable. That changes things. That changes everything.
Trivia: Believe it or not, I once asked a chemist, who studied diamonds, the temperature at which they burned. His reply was that they didn't. Instead, according to him, at about 2000 F they break down into graphite and then the graphite burns.