After a sustained lullof very little solar activity, the sun is finally coming back to life.
In mid-December,solar physicists observed a large group of sunspots that had manifested itselfon the solar surface — the largest group of sunspots to emerge for severalyears.
Scientists at theEuropean Space Agency (ESA) are studying the sunspots and how this flare-upcompares to previous levels of solar activity.
"This lastminimum was much deeper and longer than anybody predicted," said BernhardFleck, ESA's project scientist for the Solar and Heliospheric Observatory(SOHO), in a statement. "We were beginning to joke that we had enteredanother Maunder minimum."
The Maunder minimum,which occurred between 1645 and 1715, was a phase in which sunspots — visibleindicators of solar activity — were largely absent from the sun. The past twoyears have been similar, with the sun exhibiting little activity on itsspotless face over 70 percent of the time.
Sunspots are coolerregions on the surface of the sun that appear visibly dark and arecharacterized by intense magnetic fields. Typically, thesun undergoes a cycle of activity that lasts approximately 11 years. Yet,until last December, astronomers were left to grapple with the sun's apparentinaction.
Since then, however,solar activity has significantly increased. In mid-January, an even largergroup of sunspots emerged, and even more recently, several large, active areashave been making their way across the face of the sun.
Furthermore,on March 28, Thomas Ashcraft, an amateur astronomer in New Mexico, observed astrong, radio-active burst from the sun and broadcasted the news over his radiotelescope, as reported by Spaceweather.com.
Still, scientists sayit is premature to conclude that these recent events are evidence that the sunis headed toward another energetic cycle of activity.
The strength of a solar cycleis determined by the strength of the magnetism at the poles of the sun, whichis currently very weak. So, despite the Sun's increased activity in recentmonths, astronomers don't anticipate major changes to the solar cycle.
"I think we areheading for something like the early 20th century when everything was much lessactive," Fleck said. Historical records indicate that, until the last fewyears, the level of solar activity has been unusually high. As a result, thisperiod can be considered a return to more normal levels of activity, rather thana drop and resurgence.
Still, ESA's findingswill play an important role in the progress of solar observation [more photosof the sun].?
"When SOHO waslaunched almost 15 years ago, understanding the solar cycle was not one of itsscientific objectives, now it is one of the key questions," Fleck said.
As newer spacecraft,such as NASA's Solar Dynamics Observatory, are launched, SOHO scientists will beable to provide data that is consistent with NASA's newer instruments. As such,astronomers will be able to calibrate and compare datasets far more accurately.
In addition, SOHO hasthe unique capability to watch for 'coronal mass ejections' coming straight forEarth. It is the only spacecraft in line with the sun that can observe thisbehaviour, which can disrupt telecommunications, GPS and power lines.
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