New Sunspots Herald a More Active Sun
After a sustained lull of 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 itself on the solar surface the largest group of sunspots to emerge for several years.
Scientists at the European Space Agency (ESA) are studying the sunspots and how this flare-up compares to previous levels of solar activity.
"This last minimum was much deeper and longer than anybody predicted," said Bernhard Fleck, ESA's project scientist for the Solar and Heliospheric Observatory (SOHO), in a statement. "We were beginning to joke that we had entered another Maunder minimum."
The Maunder minimum, which occurred between 1645 and 1715, was a phase in which sunspots visible indicators of solar activity were largely absent from the sun. The past two years have been similar, with the sun exhibiting little activity on its spotless face over 70 percent of the time.
Sunspots are cooler regions on the surface of the sun that appear visibly dark and are characterized by intense magnetic fields. Typically, the sun undergoes a cycle of activity that lasts approximately 11 years. Yet, until last December, astronomers were left to grapple with the sun's apparent inaction.
Since then, however, solar activity has significantly increased. In mid-January, an even larger group of sunspots emerged, and even more recently, several large, active areas have been making their way across the face of the sun.
Furthermore, on March 28, Thomas Ashcraft, an amateur astronomer in New Mexico, observed a strong, radio-active burst from the sun and broadcasted the news over his radio telescope, as reported by Spaceweather.com.
Still, scientists say it is premature to conclude that these recent events are evidence that the sun is headed toward another energetic cycle of activity.
The strength of a solar cycle is determined by the strength of the magnetism at the poles of the sun, which is currently very weak. So, despite the Sun's increased activity in recent months, astronomers don't anticipate major changes to the solar cycle.
"I think we are heading for something like the early 20th century when everything was much less active," Fleck said. Historical records indicate that, until the last few years, the level of solar activity has been unusually high. As a result, this period can be considered a return to more normal levels of activity, rather than a drop and resurgence.
Still, ESA's findings will play an important role in the progress of solar observation [more photos of the sun].?
"When SOHO was launched almost 15 years ago, understanding the solar cycle was not one of its scientific 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 be able 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 has the unique capability to watch for 'coronal mass ejections' coming straight for Earth. It is the only spacecraft in line with the sun that can observe this behaviour, which can disrupt telecommunications, GPS and power lines.
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