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The Strange Case of Solar Flares and Radioactive Decay Rates

Posted by Soulskill on from the cool-science dept.

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.'"

13 of 408 comments (clear)

  1. Just to pre-empt it... by Tenek · · Score: 5, Funny

    No, this does not get you down to a 6000-year old Earth. Sorry.

    1. 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.
    2. Re:Just to pre-empt it... by Daniel+Dvorkin · · Score: 5, Insightful

      but what it *does* do is call into question the very premise that those methods are based on ... It seems that the more we study the more we find out that these things humanity has been 'sure of' at points in history are just plain wrong: the earth isn't flat, the earth isn't the center of the solar system, and maybe the earth isn't billions of years old

      TFA doesn't say how much the observed decay rates might be changing, but I really, really doubt that it's enough to make a difference to our large-scale picture of how old things are (Earth, billions of years; multicellular life, hundreds of millions of years, etc.) If the rates were that variable, we would have seen other signs of it before now. Things might turn out to be a little younger or older than we thought, but Really Old is still going to be Really Old.

      --
      The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
    3. Re:Just to pre-empt it... by sznupi · · Score: 5, Insightful

      http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm

      --
      One that hath name thou can not otter
    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.

  2. Re:In other news by Anonymous Coward · · Score: 5, Funny

    Only Pink Hat Linux. I've never gotten more trim since I made the switch to Manlyuntu.

  3. 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 c0lo · · Score: 5, Insightful
      Facts:
      1. long-term observation of the decay rate of silicon-32 and radium-226 show a small seasonal variation (on Earth conditions? With lab equipment that can be subject to other seasonal variation?)
      2. radioactive decay of the Pu-238 isotope is insensitive (within the experimental precision) to distance to the Sun

      What valid conclusion can one derive from the above facts? In my opinion, exactly one, which is more research is necessary.

      --
      Questions raise, answers kill. Raise questions to stay alive.
    2. Re:No confirmation from Cassini by wvmarle · · Score: 5, Insightful

      Both are important.

      If you can measure three significant digits, and your effect is in the fifth, then you do not see it. However a more precise measuring apparatus may measure up to six significant digits, and there the effect may become visible.

      Only when the effect becomes visible you can start saying anything about statistical significance.

      For example, I'm measuring the distance between two points. This distance is say 850 meters, and with my yardstick I can measure accurate to the meter. I do this every week for ten years and will not realise there is a fault line in between these points and they are moving apart.

      However someone else is doing the exact same measurement with laser equipment that measures to the tenth of a millimetre. He will notice that we start off at 849.8452 meters, and that ten years later it has slowly increased to 849.8473 meters.

      The first measurement reaching three significant digits does not see any effect, and quite rightfully says the distance has not changed. It indeed barely has. The second measurement that reaches seven significant digits however does see an effect. The sixth and seventh digit slowly but surely increase over the years.

      So here you see why the number of significant digits, the precision of your measurements does have an effect to whether you can see an effect or not. If your measurement is not precise enough then the effect (the slow movement of the earth's crust) disappears in the noise.

      And to come back on my previous comment: this is why the measurements on both the spacecraft (no effect) and on earth (have effect) can both be correct, and do not necessarily contradict. As half life has long been considered a constant for a certain isotope I'm sure this effect is really really small. It was pretty hard to see, and it appears only noticeable when you really start looking for it. Otherwise you will miss it. This effect seems to be on the edge of our current capabilities, and small enough to be dismissed as noise by most researchers.

  4. 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!

  5. 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!
  6. 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.

  7. Onions. On belts. by Hognoxious · · Score: 5, Funny

    Overheard in a museum:

    Boy: Mister, how old is that dinosaur skeleton?

    Curator: [after some mumbling and finger counting] 60 million and four years, eight months and sixteen days.

    Boy's mother: How can you know so accurately?

    Curator: Well, in the training course they told me it was 60 million years old. That was when I joined, which would be back in January 2006...

    --
    Confucius say, "Find worm in apple - bad. Find half a worm - worse."