To better understand fluctuations in the sun’s magnetic field, Miyahara and her team extracted individual rings from long-lived trees and estimated the strength of cosmic radiation and solar activity by measuring the amount of carbon-14 contained within. She discovered long-term changes in the basic cycle of solar activity occurring in tandem with the sun’s internal circulation speed. The growth rings on the trees were also useful to measure temperature at the time of their growth. Such data collected with accurate carbon-14 measurements could help reconstruct the 11-year solar cycle with almost the same accuracy as direct observations of the solar surface. Miyahara was awarded the 43rd Saruhashi Prize for her work.

(Photo: Project for Solar-Terrestrial Environment Prediction)