BOZEMAN – The sun has seasons, a new discovery that could help scientists understand the Earth’s climate and do a better job of predicting space weather, according to Montana State University solar physicist Robert Leamon.
Leamon was part of a team that discovered and just published its finding that the sun, like the Earth, has seasons. Instead of four seasons a year, however, the solar seasons change about once a year. The seasons result from interactions between the magnetic bands deep inside the sun.
The bands occur in both the southern and northern hemispheres of the sun. When they overlap, it affects the frequency and severity of solar flares, solar emissions and other solar activities that impact space weather, the researchers said. Sometimes the activity slows down. Other times it turns violent. Depending on the severity, it can disrupt satellite operations, cell phone service and power grids on Earth.
“Understanding the formation, interaction and instability of these activity bands will considerably improve forecast capability in space weather and solar activity,” Leamon and his collaborators said in their newly published paper.
The paper was published Tuesday, April 7, in Nature Communications, a scientific journal affiliated with the prestigious international journal, Nature. Nature Communications covers all topics in physics, chemistry, earth sciences and biology.
A press release from the National Center for Atmospheric Research (NCAR), which led the study with funding from NASA and the National Science Foundation, said the research team found that the seasonal variability means that the sun’s activity waxes and wanes over the course of nearly two years. This behavior, in turn, affects the peaks and valleys in the approximately 11-year solar cycle.
“What we’re looking at here is a massive driver of solar storms,” said Scott McIntosh, lead author of the study and director of NCAR’s High Altitude Observatory. “By better understanding how these activity bands form in the sun and cause seasonal instabilities, the potential exists to greatly improve forecasts of space weather events.”
Leamon said in the NCAR release that, “Much like Earth’s jet stream, whose warps and waves have had severe impact on our regional weather patterns in the past couple of winters, the bands on the sun have very slow-moving waves that can expand and warp it, too. Sometimes this results in magnetic field leaking from one band to the other. In other cases, the warp drags magnetic field from deep in the solar interior, near the tachocline, and pushes it toward the surface.”
The tachocline is the transition area of the sun between the interior and the outer zones.
Leamon -- an assistant research professor in MSU’s Department of Physics and currently on loan to NASA in Washington, D.C. – co-wrote the Nature Communications paper with McIntosh. Other co-authors are from the University of Colorado, Boulder; Lockheed Martin Advanced Technology Center in Palo Alto, Colo., University of California, Berkeley, the Predictive Science Inc. in San Diego, Calif., Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., the University of Michigan, Ann Arbor, Mich., and the University of California, Los Angeles.
The paper in Nature Communications came less than three weeks after another paper involving MSU ran in the same journal. Ed Schmidt, a professor in MSU’s Department of Microbiology and Immunology, and his collaborators published a paper on March 20 that described an antioxidant system that helps sustain the liver when other systems are missing or compromised.
Evelyn Boswell, (406) 994-5135 or email@example.com