Slashdot Mirror


The Strange Case of Solar Flares and Radioactive Decay Rates

DarkKnightRadick writes "Current models for radioactive decay have been challenged by, of all sources, the sun. According to the article, 'On Dec 13, 2006, the sun itself provided a crucial clue, when a solar flare sent a stream of particles and radiation toward Earth. Purdue nuclear engineer Jere Jenkins, while measuring the decay rate of manganese-54, a short-lived isotope used in medical diagnostics, noticed that the rate dropped slightly during the flare, a decrease that started about a day and a half before the flare.' This is important because the rate of decay is very important not just for antique dating, but also for cancer treatment, time keeping, and the generation of random numbers. This isn't a one time measurement, either. 'Checking data collected at Brookhaven National Laboratory on Long Island and the Federal Physical and Technical Institute in Germany, they came across something even more surprising: long-term observation of the decay rate of silicon-32 and radium-226 seemed to show a small seasonal variation. The decay rate was ever so slightly faster in winter than in summer.'"

4 of 408 comments (clear)

  1. Re:decay rates based on season? by trip11 · · Score: 5, Informative
    I read the article (yes yes I know). But in summary, your hypothesis (temperature fluctations0 was what everyone thought, but the groundbreaking bit was that they did an experiment that provides a LOT of evidence to the contrary.

    The sun has a cycle of it's own (about 1 month). They did a much more accurate study and found the decay rate is tightly correlated to the sun's cycle.

    Longer version:
    The theory now is that it has to do with the neutrino flux. As we move further from the sun the flux goes down by 1/R^2. We saw that fluctuation first. But the neutrino flux also varies with the solar cycle which is independent of the earth's temperature.

    This is very very cool experimental physics. Kudo's to them!

  2. Re:Just to pre-empt it... by Daniel+Dvorkin · · Score: 5, Informative

    I don't think anyone really believes the earth is 6000 years old.
    Just that Adam lived 6000 years ago.

    Nope, there are plenty of people around who believe that the days referred to in Genesis are literal days, that Adam was around less than a week after the Earth itself, and that all of this happened six-millennia-and-change ago. They even have a shiny web site where they explain everything.

    http://www.answersingenesis.org/get-answers#/topic/age-of-the-earth

    Don't underestimate these people. They're loons, but they're well-organized and numerous loons.

    --
    The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
  3. Re:decay rates based on season? by camperdave · · Score: 5, Informative

    Neutrino density is not going to vary a lot by hemisphere because the planet is fairly transparent to neutrinos. However, the Earth as a whole (including the southern hemisphere) is some 3% closer to the sun during the winter (January) than during the summer.

    --
    When our name is on the back of your car, we're behind you all the way!
  4. Re:Just to pre-empt it... by eleuthero · · Score: 5, Informative

    Fortunately or unfortunately, depending on your side of the debate, this is not the case.

    http://www.gallup.com/poll/27847/majority-republicans-doubt-theory-evolution.aspx

    while the title of the article focuses on Republicans, it goes on to discuss Americans in general. Fully 66% of the country holds to some form of a young creationist perspective for humanity (strangely combined with a more even distribution of views on evolution and an old planet/universe. If anything, by these numbers, which appear to hold up in other surveys, the evolutionary system appears to be the vocal minority's position. Within the survey, 38% held to a theistic evolution-esque model.