Forbush Effect

In astronomy, an occasional decrease in the intensity of cosmic rays as observed on Earth, attributed to magnetic effects produced by solar flares, which are disturbances on the Sun. The effect was discovered in 1937 by the American physicist Scott E. Forbush. Its cause became clearer in 1960, when, while the unmanned U.S. space probe Pioneer 5 was in flight some 5,000,000 km (3,000,000 miles) from Earth,