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| Science & Technology |
| Nuclear Decay Rates May Not Be A Constant |
| 2008-09-03 |
| HereÂ’s an interesting conundrum involving nuclear decay rates. We think that the decay rates of elements are constant regardless of the 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 the curious periodic variations in the decay rates of silicon-32 and radium-226 observed by groups at the Brookhaven National Labs in the US and at the Physikalisch-Technische Bundesandstalt in Germany in the 1980s. Today, the story gets even more puzzling. Jere Jenkins and pals at Purdue University in Indiana have re-analysed the raw data from these experiments and say that the modulations are synchronised with each other and with EarthÂ’s distance from the sun. (Both groups, in acts of selfless dedication, measured the decay rates of silicon-32 and radium-226 over a period of many years.) In other words, there appears to be an annual variation in the decay rates of these elements. Jenkins and co put forward two theories to explain why this might be happening. First, they say a theory developed by John Barrow at the University of Cambridge in the UK and Douglas Shaw at the University of London, suggests that the sun produces a field that changes the value of the fine structure constant on Earth as its distance from the sun varies during each orbit. Such an effect would certainly cause the kind of an annual variation in decay rates that Jenkins and co highlight. Another idea is that the effect is caused by some kind of interaction with the neutrino flux from the sunÂ’s interior, which could be tested by carrying out the measurements close to a nuclear reactor (which would generate its own powerful neutrino flux). It turns out, that the notion of that nuclear decay rates are constant has been under attack for some time. In 2006, Jenkins says the decay rate of manganese-54 in their lab decreased dramtically during a solar flare on 13 December. And numerous groups disagree over the decay rate for elements such as titanium-44, silicon-32 and cesium-137. Perhaps they took their data at different times of the year. |
| Posted by:Anonymoose |
| #11 So Voyager, Pioneer etc... all carry reactors on their exit from the solar system. Any way to infer rates from their power fluxes? |
| Posted by: 3dc 2008-09-03 19:20 |
| #10 Glenmore, A hint--except in a few special cases where beta decay can be influenced by powerful electric fields Wouldn't you suspect that may be the case here? Neutrino flux idea is a dead trail. |
| Posted by: Spike Uniter 2008-09-03 14:44 |
| #9 Silentbrick: at the moment it appears to average out over a period of about a year. But then again, that's knowing nothing about the causation behind the effect. |
| Posted by: Abdominal Snowman 2008-09-03 13:58 |
| #8 This will have very interesting impacts on the field of geology, DEPENDING on the variation. If the variation is relative tiny over the course of geologic time, ie 1-2 millions years difference over billions, as geologists, we're gonna mostly say, "Meh. Who cares." But if it's alot of variance, that's going to have some serious implications. Will have to bring this to the attention of the professors. |
| Posted by: Silentbrick 2008-09-03 13:36 |
| #7 OldSpook: This can have strong implications throughout science. Not just carbon dating, but nuclear clocks and timers, nuclear medicine, quantum and particle physics, and the list goes on and on. Science is very reliant on constants, of which there are not that many in the universe. If one turns out to be a variable, it can throw a monkey wrench into the machinery. |
| Posted by: Anonymoose 2008-09-03 11:57 |
| #6 #3, I wonder if that could influence the design output of an atomic power supply (if it doesn't explode or die(grin))? |
| Posted by: tipover 2008-09-03 11:21 |
| #5 Wow. Solar activity influence decay rates? Sun spots affect it? Yet solar activity does not do anything to the global climate compared to human greenhouse gas emissions. According to the "climate change" high priests. All that aside, this is quite odd, and may have impacts on other things, like carbon dating, which assumes a constant half-life decay rate. |
| Posted by: OldSpook 2008-09-03 11:17 |
| #4 Geordi will just reverse the polarity. Things will be fine. He does that all the time. |
| Posted by: Steve White 2008-09-03 11:13 |
| #3 What would be the effect on the nuclear power plants on deep space explorers? If the small variations in distance from the sun generate measureable variations in decay rate, will the Uranium (or whatever) in the generators either go dead or explode violently beyond the solar system? |
| Posted by: Glenmore 2008-09-03 11:01 |
| #2 Hmmm - I always thought that decay rates were random for individual atoms, but statistically constant for large numbers of atoms over long time periods. I'd love to see the data. |
| Posted by: Spot 2008-09-03 10:49 |
| #1 Boy, that's going to effect the specification alignments on the warp coil. Better let Geordi know down in engineering. |
| Posted by: Procopius2k 2008-09-03 10:12 |