Solar Flares, Neutrinos and Radioactive Decay: A Bizarre Love Triangle

Posted by: Mike Pallante on April 25, 2011 at 11:12AM
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Does Solar Flare Activity Effect the Rate of Radioactive Decay on Earth?

In February 2011 Earth witnessed the largest Coronal Mass Ejection, or Solar Flare, in nearly four years. For most people the flare meant a brighter Aurora Borealis. Thankfully, the Earth's atmosphere absorbed the blast of charged solar particles from the sun's corona. However, for radioactive elements across the planet the flare may have caused a decrease in radioactive decay.

Scientists consider radioactive decay a constant. We use the steady decay of Carbon-14, an element common to all life, to date ancient artifacts. However an accidental discovery by Ephraim Fischbach, a Perdue University Physicist, uncovered an embarrassing fact: although scientists agreed radioactive decay had a constant rate they did not agree on that rate. Published data from different scientists on the same isotopes reported different decay rates.

Fischbach's team compared data from research laboratories in the US and Germany and came across an even more more unexpected discovery: the variations in decay rate varied seasonally. In summer silicon-32 and radium-226 decayed slightly slower than in winter, for example.

Isotope Decay Rates Seem to Change with the Seasons

When experts ruled out equipment malfunction they were left with a puzzling situation and no explanation. Why were isotope decay rates changing with the seasons? It seemed the mystery would never be solved. Then nature threw researchers a clue. In December of 2006 a major solar flare occurred. While studying manganese-54, Jere Jenkins, another Perdue University physicist, noticed a sudden drop in decay rate. What's more, the drop began the evening before the solar flare. Jenkins lab was faced away from the Sun meaning if solar particles were affecting his isotope they had to first pass through the Earth to reach his lab.

Neutrinos - Kind of Like Solar Ghosts

The obvious culprit seemed to be neutrinos, an elementary particle which travels at near light speed. Neutrinos are nearly massless, which enables them to travel so fast, much like Electrons. Except neutrinos do not carry an electric charge;meaning they are not affected by electromagnetism. Neutrinos only interact with the weak-nuclear force and gravity. The weak-nuclear force is responsible for radioactive decay and atomic fusion.

If solar flares blasting neutrinos at earth are causing changes in the decay rates of radioactive isotopes, scientists may soon have data to prove it. Until now it was thought neutrinos rarely, if at all, interacted with normal matter - a fact which has made them notoriously difficult to detect. Finding data on the ebb, flow and volume of neutrinos to compare with the variance in atomic decay has been difficult.

Researchers Hope to Find Answers Using The Largest Neutrino Detection Facility - Super-K

Fortunately for researchers Japan has built one of the largest and most advanced neutrino detection facilities ever conceived. The Super-Kamiokande, or Super-K for short, consists of 13,000 sensors embedded in a massive underground pool. Unfortunately the effects of the Fukishima nuclear crisis on the Super-K are yet unknown. The two sites are only 240 miles apart.



While the Super-K is the most advanced neutrino observation facility it is not the only one. In South Dakota, 4,850 feet below the ground in the Homestake goldmine, researchers have filled a tank with 600 tons of chlorine rich water. It is suspected that when Neutrinos collide with chlorine, an admittedly rare occurrence, an argon atom is released. Further, by placing the facility so far under ground researchers can rule out many of the particles found on the earth's surface. Remember, neutrinos can pass through the Earth unaffected. By measuring the amount of argon atoms produced in the chlorine environment researchers can guess at the amount of neutrinos.

Solar Maximum - The 2012 Phenomenon

The solar flares of 2006 and 2011 were both welcome events for researchers studying neutrinos and radioactive decay alike. But the big show is yet to come. In 2012 the sun will experience what is called “Solar Maximum”, a peak of activity during the sun's 11 year solar cycle. If neutrinos are affecting atomic decay on earth, researchers will have their best chance in a decade to measure both the volume of neutrinos, which should peak for the first time since the creation of the new neutrino observatories, and atomic decay, which should slow the most since Fischbach presented his theory.