Slashdot Mirror
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.
They are just trying to force me to buy new updated nuclear engineering text books. I won't fall for it!
Nuclear engineers build weapons. Civil engineers build targets.
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?
Are the reasons your extensive diamond knowledge will never come in handy.
You better watch out, there may be dogs about . .
The Voyagers was the first thing that came to my mind, too. If the rate of radioactive decay is dependent on neutrino flux from the sun, then shouldn't their RTGs have long since gone dead as the rate of decay slowed (due to increasing distance), rather than maintaining better performance than originally anticipated (due to better performance of the thermocouple than anticipated)? (NASA link) Given that both spacecraft are alive and well out past the heliosphere, I think we can safely conclude that the rate of decay of the plutonium onboard is not meaningfully influenced by solar neutrino flux.
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.
...only if they maintain the correct Bond.
Find environmentally and socially responsible products on http://buy-right.net
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