Via slashdot:
A couple of days ago, WUWT carried a story that was rather shocking: some physicists published claims they have detected a variation in earthly radioactive decay rates, big news by itself, but the shocker is they attributed it to solar neutrinos.
The findings attracted immediate attention because they seemed to violate two known basic facts of physics:
1. Radioactive decay is a constant
2. Neutrinos very rarely interact with matter and are hard to detect when they do.
For example: trillions of the neutrinos are zipping through your body right now. So why would they interact with radioactive elements in a more detectable way?
Discover Magazine’s blog 80beats followed up on the initial story buzzing around the web this week and interviewed several physicists who work on neutrinos. The neutrino-affecting-radioactive decay theory is being questioned.
Excerpts:
“My gut reaction is one of skepticism,” Sullivan told DISCOVER. The idea isn’t impossible, he says, but you can’t accept a solution as radical as the new study’s with just the small data set the researchers have. “Data is data. That’s the final arbiter. But the more one has to bend [well-establish physics], the evidence has to be that much more scrutinized.”
Among the reasons Sullivan cited for his skepticism after reading the papers:
- Many of the tiny variations that the study authors saw in radioactive decay rates came from labs like Brookhaven National Lab—the researchers didn’t take the readings themselves. And, Sullivan says, some are multiple decades old. In their paper, Fischbach’s team takes care to try to rule out variations in the equipment or environmental conditions that could have caused the weird changes they saw in decay rates. But, Sullivan says, “they’re people 30 years later [studying] equipment they weren’t running. I don’t think they rule it out.”
- The Purdue-Stanford team cites an example of a 2006 solar flare, saying that they saw a dip in decay rates in a manganese isotope before the occurrence that lasted until after it was gone. Sullivan, however, says he isn’t convinced this is experimentally significant, and anyway it doesn’t make sense: Solar neutrinos emanate from the interior of the sun—not the surface, where flares emerge. Moreover, he says, other solar events like x-ray flares didn’t have the same effect.
- If it were true, the idea would represent a huge jump in neutrino physics. At the Super-Kamiokande detector, Sullivan says only about 10 neutrinos per day appeared to interact with the 20 kilotons of water. Sullivan says the Purdue-Stanford team is proposing that neutrinos are powerfully interacting with matter in a way that has never before been observed. “They’re looking for something with a very much larger effect than the force of neutrinos, but that doesn’t show up any other way,” he says.
Fischbach and Jenkins, who have published a series of journal articles supporting their theory on neutrinos and radioactive decay, emailed DISCOVER to respond to these criticisms of their work. Regarding the first one, the researchers defended the integrity of the data even though they didn’t take it themselves, saying the experiments “were carried out by two well-known and experienced groups. We have published an analysis of these experiments, in Nuclear Instruments and Methods … showing that the potential impact of known environmental effects is much too small to explain the annual variations.”
Jarek Duda :
August 29, 2010 at 8:01 am
Any interaction, absorption or scattering or what have you, of a neutrino with another particle or field has to be mediated by the weak interaction or the gravitational interaction . This introduces an extra weak vertex in the calculation of the cross section , which is what will give the factor 10^-12. Gravitation is much worse, would introduce a 10^-74 or so.
Nothing is excluded, it is just that it is very very small to give a measurable effect of 0.2%.
Very interesting indeed!
PS: Has Big Al come out and said what the truth of all this really is? Ya know, the science isn’t settled and the game ain’t over til’ The Fat Boy sings!
anna v says:
August 29, 2010 at 11:42 am
“Any interaction, absorption or scattering or what have you, of a neutrino with another particle or field has to be mediated by the weak interaction or the gravitational interaction .”
Only if those are the only interactions of which neutrinos are capable, which we do not and cannot know. All we know is that those are the only interactions seen within the regimes so far investigated (and the only ones our current theories envisage). Any time we enter a new and untested regime the possibility that some previously unobserved interactions will be manifest cannot be excluded. Experimental test of the theory in each new regime is essential.
Now, since stronger effects are usually discovered before weaker effects, it is on the face of it rather unlikely that any new neutrino interactions will prove so much stronger than those already known that they could explain this reported effect; nevertheless, science is full of seemingly unlikely discoveries. It could be, for example, that the neutrinos mediating the effect are a very different type of neutrino from the ordinary ones normally detected – perhaps some sort of gravitino or heavy neutrino – or some other particle altogether. This is, of course, sheer speculation, but the possibility of such weird and wonderful particles existing outside the standard model is a fairly common speculation in particle physics.
Note: if perchance there already does exist experimental evidence relating to this regime, which would conclusively rule out mediation by solar neutrinos (or other particles), I should be interested to learn of it. So far as I am aware, all the other evidence (apart from the previously mentioned observations of solar neutrinos) relates to significantly different situations, which are not directly comparable.
Third attempt to post this article about THORIUM
‘…..There is no certain bet in nuclear physics but work by Nobel laureate Carlo Rubbia at CERN (European Organization for Nuclear Research) on the use of thorium as a cheap, clean and safe alternative to uranium in reactors may be the magic bullet we have all been hoping for, though we have barely begun to crack the potential of solar power. Dr Rubbia says a tonne of the silvery metal – named after the Norse god of thunder, who also gave us Thor’s day or Thursday – produces as much energy as 200 tonnes of uranium, or 3,500,000 tonnes of coal. A mere fistful would light London for a week. Thorium eats its own hazardous waste. It can even scavenge the plutonium left by uranium reactors, acting as an eco-cleaner. “It’s the Big One,” said Kirk Sorensen, a former NASA rocket engineer and now chief nuclear technologist at Teledyne Brown Engineering. “Once you start looking more closely, it blows your mind away. You can run civilisation on thorium for hundreds of thousands of years, and it’s essentially free. You don’t have to deal with uranium cartels,” he said.
Thorium is so common that miners treat it as a nuisance, a radioactive by-product if they try to dig up rare earth metals. The US and Australia are full of the stuff. So are the granite rocks of Cornwall. You do not need much: all is potentially usable as fuel, compared to just 0.7pc for uranium. After the Manhattan Project, US physicists in the late 1940s were tempted by thorium for use in civil reactors. It has a higher neutron yield per neutron absorbed. It does not require isotope separation, a big cost saving. But by then America needed the plutonium residue from uranium to build bombs.
“They were really going after the weapons,” said Professor Egil Lillestol, a world authority on the thorium fuel-cycle at CERN. “It is almost impossible make nuclear weapons out of thorium because it is too difficult to handle. It wouldn’t be worth trying.” It emits too many high gamma rays. You might have thought that thorium reactors were the answer to every dream but when CERN went to the European Commission for development funds in 1999-2000, they were rebuffed.
Brussels turned to its technical experts, who happened to be French because the French dominate the EU’s nuclear industry. “They didn’t want competition because they had made a huge investment in the old technology,” he said.
Another decade was lost. It was a sad triumph of vested interests over scientific progress. “We have very little time to waste because the world is running out of fossil fuels. Renewables can’t replace them. Nuclear fusion is not going work for a century, if ever,” he said. The Norwegian group Aker Solutions has bought Dr Rubbia’s patent for the thorium fuel-cycle, and is working on his design for a proton accelerator at its UK operation. Victoria Ashley, the project manager, said it could lead to a network of pint-sized 600MW reactors that are lodged underground, can supply small grids, and do not require a safety citadel. It will take £2bn to build the first one, and Aker needs £100mn for the next test phase. The UK has shown little appetite for what it regards as a “huge paradigm shift to a new technology”. Too much work and sunk cost has already gone into the next generation of reactors, which have another 60 years of life.
So Aker is looking for tie-ups with the US, Russia, or China. The Indians have their own projects – none yet built – dating from days when they switched to thorium because their weapons programme prompted a uranium ban. America should have fewer inhibitions than Europe in creating a leapfrog technology. The US allowed its nuclear industry to stagnate after Three Mile Island in 1979. Anti-nuclear neorosis is at last ebbing. The White House has approved $8bn in loan guarantees for new reactors, yet America has been strangely passive. Where is the superb confidence that put a man on the moon? A few US pioneers are exploring a truly radical shift to a liquid fuel based on molten-fluoride salts, an idea once pursued by US physicist Alvin Weinberg at Oak Ridge National Lab in Tennessee in the 1960s. The original documents were retrieved by Mr Sorensen. Moving away from solid fuel may overcome some of thorium’s “idiosyncracies”. “You have to use the right machine. You don’t use diesel in a petrol car: you build a diesel engine,” said Mr Sorensen. Thorium-fluoride reactors can operate at atmospheric temperature. “The plants would be much smaller and less expensive. You wouldn’t need those huge containment domes because there’s no pressurized water in the reactor. It’s close-fitting,” he said.
Nuclear power could become routine and unthreatening. But first there is the barrier of establishment prejudice. When Hungarian scientists led by Leo Szilard tried to alert Washington in late 1939 that the Nazis were working on an atomic bomb, they were brushed off with disbelief. Albert Einstein interceded through the Belgian queen mother, eventually getting a personal envoy into the Oval Office.
Roosevelt initially fobbed him off. He listened more closely at a second meeting over breakfast the next day, then made up his mind within minutes. “This needs action,” he told his military aide. It was the birth of the Manhattan Project. As a result, the US had an atomic weapon early enough to deter Stalin from going too far in Europe.
The global energy crunch needs equal “action”. If it works, Manhattan II could restore American optimism and strategic leadership at a stroke: if not, it is a boost for US science and surely a more fruitful way to pull the US out of perma-slump than scattershot stimulus. Even better, team up with China and do it together, for all our sakes……………’
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I really think this sounds interesting as far as an alternative move from the oil economy even though the plants need the CO2. From an article in the Telegraph
‘…Dr Rubbia says a tonne of the silvery metal – named after the Norse god of thunder, who also gave us Thor’s day or Thursday – produces as much energy as 200 tonnes of uranium, or 3,500,000 tonnes of coal. A mere fistful would light London for a week.
Thorium eats its own hazardous waste. It can even scavenge the plutonium left by uranium reactors, acting as an eco-cleaner. “It’s the Big One,” said Kirk Sorensen, a former NASA rocket engineer and now chief nuclear technologist at Teledyne Brown Engineering.
“Once you start looking more closely, it blows your mind away. You can run civilisation on thorium for hundreds of thousands of years, and it’s essentially free. You don’t have to deal with uranium cartels,” he said.
Thorium is so common that miners treat it as a nuisance, a radioactive by-product if they try to dig up rare earth metals. The US and Australia are full of the stuff. So are the granite rocks of Cornwall. You do not need much: all is potentially usable as fuel, compared to just 0.7pc for uranium.
After the Manhattan Project, US physicists in the late 1940s were tempted by thorium for use in civil reactors. It has a higher neutron yield per neutron absorbed. It does not require isotope separation, a big cost saving. But by then America needed the plutonium residue from uranium to build bombs.
“They were really going after the weapons,” said Professor Egil Lillestol, a world authority on the thorium fuel-cycle at CERN. “It is almost impossible make nuclear weapons out of thorium because it is too difficult to handle. It wouldn’t be worth trying.” It emits too many high gamma rays………………………’
Wow.
“”” jtom says:
August 28, 2010 at 10:39 pm
“http://scienceblog.com/light.html”
Wow, whoever wrote that article has no idea at all of index of refraction, speed of light in optical fiber, or what was the significant about the research in question. Makes me wonder what other misinformation is sitting out there on such blogs.
The phrase, “the speed of light is a constant,” is taken out of context. The correct wording is, “the speed of light IN A VACUUM is a constant.” The speed of light is dependent upon the medium it is traveling in, and can derived from the medium’s index of refraction. The speed of light in typical optical fiber is approximately 2/3 that of a vacuum (i.e., space). It has also long been known that some materials have indexes of refraction whose values are such that the speed of light is faster in the materials than in a vacuum. “””
Well don’t you also have to be careful as to what velocity you are specifying. It is the “group” veliocity of light in a vaccuum (c) that is constant; and also now has an exact value. The “phase” velocity is what can exceed the group velocity.
Simplest demonstration idea, is to imagine an ocean wave that is approaching a sea wall head on so that the crest of the wave hits every point on the wall at the same instant of time probably creating a big wash along the whole wall, that goes up and over the wall.
Now tilt the wave off the normal to the wall, by some small angle (say one degree). The wave still approaches the wall at exactly the same velocity, but now the contact of the wave crest with the wall runs along the wall at many times the actual velocity of the wave.
To an observer watching the high point of the wave as it appears to race along the wall, he sees the wave crest running along the wall at 57.3 times the actual velocity of the wave.
Well of course nothing is moving along the wall at that speed; the water that forms the crest a mile down the wall is not the same water that hit the wall down the other end just a fraction of a second ago. No information is propagating along the wall at that enhanced speed.
Detailed story about this on Fermilab’s webzine:
http://www.symmetrymagazine.org/breaking/2010/08/23/the-strange-case-of-solar-flares-and-radioactive-elements/
Comments are always interesting, these are some really sharp folks! Theoretical physicists etc.
If radioactive decay rates decrease, then the radiation given off by the core of a nuclear weapon would decrease. The cores critical mass would increase and more/denser core material would be required for warhead detonation. What if the force that can decrease radioactive decay could also increase it? How much increase would it require for a nuclear weopon to spontaneously reach critical mass?
That wud be a nice movie script indeed. 8)