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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.'"

6 of 408 comments (clear)

  1. No confirmation from Cassini by MMatessa · · Score: 5, Interesting

    One way to double-check the seasonal variation effect is to look at the output level on radioisotope power sources in spacecraft. Cooper (2008) found no relationship between radioactive decay and distance to the sun.

    1. Re:No confirmation from Cassini by AJWM · · Score: 4, Interesting

      Except that Cassini isn't measuring the decay rate, as the other experiments were directly, but measuring the power output from thermocouples heated by the energy of the particles captured (by the overall mass of the thermocouple/isotope system) from the decaying material -- which also has a rather long half-life.

      There's a lot of averaging out of effects in all that, and the effect they're looking for is quite small. The link didn't mention a lower bound for the detection sensitivity based on looking at Cassini power outputs. Cassini doesn't rule it out, it just sets an upper bound for the effect -- and if the effect were that strong we'd likely have noticed it before now.

      --
      -- Alastair
  2. Re: Just to pre-empt it... by Black+Parrot · · Score: 4, Interesting

    Just like, as is proven by history, at least a couple of million Chinese and Egyptians.

    Genesis literalists like to "show" that if you started with eight people around the assumed time of the flood, it takes only a modest exponential growth rate to get the world's current population. Too bad they don't pause to consider what their curve predicts for just a few hundred years beyond the starting point.

    And therein lies, I think, the big cognitive difference between scientists and traditionalists. Scientists are all over their own hypotheses with "what about this?" questions, but a traditionalist doesn't look beyond the most superficial analysis if it gives the desired result.

    --
    Sheesh, evil *and* a jerk. -- Jade
  3. Re:Question by Angst+Badger · · Score: 3, Interesting

    The trouble is that the effect is correlated with the 33-day rotation of the solar core. If varying rates of nuclear decay affected cancer rates -- which they could -- the problem with measuring it is the speed with which cancer progresses. Since we can't detect cancer the moment a cell goes rogue, any variability in oncogenesis rates over a 33-day period would be lost in the statistical noise.

    If you do figure out a way to detect oncogenesis that precisely, you'll be too busy curing cancer to worry much about solar neutrino flux.

    --
    Proud member of the Weirdo-American community.
  4. Re:Earth Date by wvmarle · · Score: 5, Interesting

    They found the same results in historical data of various labs. That of course does not rule out such a mundane reason, it makes it less likely.

    I agree that there are certainly seasonal variations in labs, even if you try to keep it as constant as possible. But for starters the air in the lab has to be refreshed all the time, and this air comes from the outside. I can imagine the composition changes between summer and winter (plants don't grow in winter).

    The 33-day cycle another replier mentioned is interesting of course, as it correlates with a solar cycle and no normal human cycles.

    A multi-year cycle correlating to solar spots could be interesting.

    Effects correlating to known solar flares too.

  5. Re:decay rates based on season? by realityimpaired · · Score: 4, Interesting

    I'm pretty sure that's exactly why darkmeleon suggested doing the experiment in the southern hemisphere: it's a great way to either prove or disprove those saying that temperature variation is what's causing the change in measured decay rates: if it's caused by the weather's effect on the equipment, then the effect should be out of phase in the southern hemisphere than the northern. If, on the other hand, the increase/decrease happens in the same months, then it confirms that it's the proximity to the sun that's causing it.