科学家发现测定太阳活动周期的新线索

Approximately every 11 years, the sun undergoes a complete personality change from quiet and calm to violently active. The height of the sun's activity, known as solar maximum, is a time of numerous sunspots, punctuated with profound eruptions that send radiation and solar particles out into the far reaches of space. However, the timing of the solar cycle is far from precise. Since humans began regularly recording sunspots in the 17th century, the time between successive solar maxima has been as short as nine years, but as long as 14, making it hard to determine its cause. Now, researchers have discovered a new marker to track the course of the solar cycle -- brightpoints, little bright spots in the solar atmosphere that allow us to observe the constant roiling of material inside the sun. These markers provide a new way to watch the way the magnetic fields evolve and move through our closest star. They also show that a substantial adjustment to established theories about what drives this mysterious cycle may be needed.

Historically, theories about what's going on inside the sun to drive the solar cycle have relied on only one set of observations: the detection of sunspots, a data record that goes back centuries. Over the past few decades, realizing that sunspots are areas of intense magnetic fields, researchers have also been able to include observations of magnetic measurements of the sun from more than 90 million miles away.

"Sunspots have been the perennial marker for understanding the mechanisms that rule the sun's interior," said Scott McIntosh, a space scientist at the National Center for Atmospheric Research in Boulder, Colorado, and first author of a paper on these results that appears in the September 1, 2014, issue of the Astrophysical Journal. "But the processes that make sunspots are not well understood, and far less, those that govern their migration and what drives their movement. Now we can see there are bright points in the solar atmosphere, which act like buoys anchored to what's going on much deeper down. They help us develop a different picture of the interior of the sun."