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.
“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.”