Violent solar flare is preview of space weather to comeBy Robert Roy Britt, explorezone.com
NASA researchers said the solar flare erupted in the Sun's southern hemisphere, shooting material in a direction that will mostly miss our planet. The only expected effect is increased auroral activity, the colorful Southern and Northern Lights.
White-light image of Sun in July shows sunspots. Solar flares, one type of "space weather" associated with the solar maximum, release tremendous amounts of energy, equivalent to a million hundred-megaton nuclear explosions, in just moments. Scientists are still trying to understand solar flares and coronal mass ejections. While the basics are known, there is much that remains unclear, including exactly how solar flares relate to coronal mass ejections, which scientists call CME's. "During solar maximum we often have more than one coronal mass ejection every day," said David Hathaway, a solar physicist at the Marshall Space Flight Center. "The basic cause of CME's is fairly well understood. Like solar flares, they occur whenever there's a rapid, large-scale change in the magnetic field. Solar flares and CME's often occur together, as they did this weekend, but not necessarily because the flare triggers the CME or vice versa. One can happen without the other and frequently during solar maximum we see CME's without an associated flare." The peak is coming
Scientists call the current phase Cycle Number 23, and the peak is expected to come sometime between this fall and the middle of next year. The frequency of solar flares is expected to increase with the number of sunspots during the rise to the maximum. Researchers say major flares will continue for two or three years afterward. Though the event is not expected to be any worse than previous cycles, modern communications systems -- which rely increasingly on satellites -- are more vulnerable. Past solar maximums, which are tied to increases in sunspot activity, have been known to disrupt satellite communications and cause widespread power blackouts on Earth. Cellular telephones, pagers and the Global Position System -- used for airline navigation -- could be particularly vulnerable, experts say. The last peak, in 1989, caused power blackouts, knocked satellites out of orbit and disrupted radio communications. Other effectsThese violent flares may affect more than just satellites and power grids. An active Sun, known to heat the Earth's outer atmosphere, may also alter our climate. Scientists say a small ice age from 1645 to 1715 corresponded to a time of reduced solar activity, and current rises in temperatures might be related to increased solar activity. For northern residents, more solar radiation means an increase in the aurora borealis, or northern lights. The solar wind sends charged particles crashing into Earth's atmosphere every day. These particles are attracted to the poles by Earth's magnetosphere, where they excite molecules of nitrogen and oxygen and create the colorful displays of light. The displays should be more pronounced over the next two years. |
The solar flare erupted from a complex group of sunspots,
according to NASA. The x-ray emissions were measured by the GOES 8
satellite, and researchers said the flare was an "X" class event,
the most powerful. A weaker "M" class flare erupted from the same
sunspot group on Friday, August 27. 
The Sun is currently in the midst of its rise toward
a peak of sunspot activity that has for some time been expected to
occur between 1999 and 2004. This graphic shows the number of sunspots
in past cycles and the recent rise in the current cycle. [Source:
NASA] 
