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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?"
On a timescale of billions of years, however, the luminosity of the Sun has increased substantially, and if that accelerates radioactive decays by some neutrino interaction then the uranium-lead clock would be off and the Earth might be considerably older than we thought.
Real Daleks don't climb stairs - they level the building.
Probably not. The change in decay rate was on the order of .1% (see Fig. 1 of the paper), which is I believe smaller than the error in carbon (or other radioactive) dating. Also, it is only these two isotopes that are mentioned, presumably because most other isotopes tested do not have this sort of periodic effect.
Does this have any ramifications for carbon dating?
Seriously : No.
For 2 reasons.
I. - Effect on carbon
For now carbon isn't on the list of the elements that seem affected by the distance to the sun.
II. - Not a significant variation. :
in TFA, variation seem to be very well correlated with the distance *BUT* these variations are really small : only a small fraction of percent (~0.15%). To cite one of the commenters on TFA's blog thread
That said, itâ(TM)s not *terribly* unsettling to me; the variations are small (measurable,but small) and to me itâ(TM)s all part of the Wonderful World of the Weird that is QM.
If we discover that carbon is among the elements influenced by the sun too, those mere ~0.15% of variation will be insignificant compared to the skew that happens with varying concentration of carbon-14 in the atmosphere (see wikipedia's graph of variation) - which already requires that we do calibrations anyway.
(Current carbon dating doesn't extrapolate the age purely by deducing the levels from the decay rate, but instead uses tables where corrections have been inserted based on the carbon dating of thing with known age)
So in short : for now it doesn't have any ramification and anyway it couldn't have any more than we already compensate for.
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
Actually a cesium clock uses the hyperfine structure which is not known to be affected these effects.
Inventions have long since reached their limit, and I see no hope for further development.-- Frontinus, 1st cent. AD
Actually the more radioactive something is the faster it decays. Uranium in waste is not the problem, the minor actinides are.
Inventions have long since reached their limit, and I see no hope for further development.-- Frontinus, 1st cent. AD
I am more concerned about the other end of that - time-keeping --- the communications networks get their time hacks from clocks based upon the decay rate of isotopes (e.g. a cesium clock).
Caesium clocks have nothing to do with nuclear decay rates. They measure electron state transition times. You can relax now.
I get your joke, but it presents an opening to state the following little known fact:
Diamonds are not, in fact, forever
Under normal temperature and pressure conditions, diamond is not the most stable form of carbon - graphite is. Using thermodynamic arguments and building a free energy curve, one can show that some fraction of a diamond must decay to graphite in order to achieve a minimum energy state. It does take a very long time for this to happen - geologic time - but even a "long time" is not forever. If you aren't that patient, heat the diamond up to, say, 1500 C to speed things up. Oh, but be sure to do that in the absence of oxygen, because diamond burns just like other forms of carbon.
Some references: [1], [2], [3]
The communications networks get their time hacks from clocks based upon the decay rate of isotopes (e.g. a cesium clock).
It's actually based on the frequency of a transition in cesium, but the point is that these transitions are sensitive to the fine structure constant. If some field from the sun is changing that, it should be detectable in atomic clocks.
Short answer: no.
Longer answer: nope.
Even longer answer:
1. Carbon isn't one of the isotopes that are affected by this.
2. The fluctuations have a period of about year, so they average out when you measure something over millenia.
3. The fluctuations are very very tiny, waay below one percent even. So basically even if you happened to take one extreme as your value, and in reality it was the opposite extreme, and even with "compound interest" so to speak... worst that could happen is that a 100,000 year old bone turns out to be "only" a bit over 99,000 year old. The creationists still aren't going to like it.
4. The variability in C14 production and distribution are much bigger than this fluctuation, and we learned to deal with those perfectly well. (C14 is constantly produced as neutrons from solar radiation knock off and replace a proton from an N14 atom, turning it into a C14 atom.)
5. The way we deal with those is by calibrating that dating. There's stuff that we already know when it happened, by other means (chronicles, geologic events, etc), and we can see how much C14 is left in stuff from that year. That lets you calibrate your C14 dating pretty damn well.
The last one also tells you why actually #2 is the only one that matters: we already calibrated for long intervals, and such fluctuations were already averaged into the calibration. This new discovery won't affect C14 dating at all. The effect is exactly zero. Null. Nada. Nix.
Of course, that won't stop young-Earth creationists from coming out of the woodwork, and waving yet another thing they don't understand as "proof" that science is wrong and their bible is the literal history of Earth. What else is new? No, seriously.
I figure everyone and everything has their place and role, though. The young-earth creationists' is simply to make everyone else look smart. It's a tough job, but someone has to do it ;)
A polar bear is a cartesian bear after a coordinate transform.
The variation would be over the course of a year, and carbon dating works on a timescale of centuries to millennia; it would even out.
Is that assuming the only measurable factor is based upon the distance from the sun? Because that would seem to be an incomplete description of radiation, especially since the article mentioned the possibility of solar flare activity causing the decay rate to change.
The old axiom of "The more I learn, the less I know" could very well hold true for this subject matter.
The Fine structure addressed in this article is not the hyperfine structure which cesium clocks use.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Diamonds are generally best friends, not dating material.
No, dogs are best friends around here. What women read /.?
It is dangerous to be right when the government is wrong.
If I understood correctly, the variance in decay rate between Earth's aphelion and perihelion is .1%. Earth's distance from the sun doesn't change by that much in astronomical terms...
But Earth's distance from the sun does change by more than 0.1% during its orbit:
Aphelion distance = 152.1 million km
Perihelion distance = 147.3 million km
So aphelion distance from the center of the sun is 3.2% greater than perihelion distance. Alternatively, both aphelion and perihelion differ from their mean by 1.6%.
Those who can make you believe absurdities can make you commit atrocities. - Voltaire
At least with regards to carbon dating, it has been known for some time that strict carbon dates are not accurate. These are referred to as "uncalibrated" dates. The explanation that I remember seeing is that the atmospheric ratio of C14/C12 has not been constant over the earth's history, but this may be a factor as well. At any rate, carbon dates for at least the last 15,000 years can be calibrated - that is, the concentration of C14 in the object being tested can be compared to the concentration of C14 in an object of a known age (e.g. from tree rings, ice cores, documented historical sites) to get a more accurate assessment of an objects age. In some cases this can lead to objects being considerably older than originally thought. For example, an uncalibrated carbon date of 9,000BC corresponds to a calibrated carbon date of nearly 11,000BC.
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