The more things change, the more they stay the same. That old adage accurately describes the behavior of the solar magnetic field revealed by a new study. Waxing and waning, even flipping direction, the sun's magnetic field undergoes dramatic upheavals yet always returns to its original shape and position.
"The sun's magnetic field has a memory and [has returned] to approximately the same configuration" during each of the past three solar-activity cycles, says Marcia Neugebauer of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. She and her JPL colleagues base their finding, described in the Feb. 1 Journal Of Geophysical Research, on an analysis of 250,000 hours of solar data compiled by spacecraft between 1960 and 1998.
Current theories, she notes, suggest that random, churning motions of charged particles within the sun generate the solar magnetic field, so it should have no long-term memory. "Despite this expectation, the underlying magnetic struct