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Forecast calls for calmer space weather

Different instruments on the SOHO satellite produced this composite image of a January 4 monster eruption from the sun.
Different instruments on the SOHO satellite produced this composite image of a January 4 monster eruption from the sun.  


By Richard Stenger
CNN

(CNN) -- The tumultuous sun appears to be calming down, becoming less likely to unleash intense bursts of energy that wreak havoc around the Earth, according to astronomers.

Weeks ago, NASA scientists said that the great ball of fire appeared to have reached a second peak of activity. Yet this week, Harvard astrophysicists predicted that the stormy sun would steadily transform into a gentle giant in the coming years.

"As we approached solar minimum, only five years away, the sun will produce fewer solar flares and fewer coronal mass ejections," the Harvard-Smithsonian Center for Astrophysics researchers said in a statement.

Such outbursts of highly charged particles, if directed toward Earth, can smash into the upper atmosphere, producing colorful aurora displays and making electrical systems go haywire on everything from satellites to power grids.

The frequency and intensity of such storms coincide with the waxing and waning of the sun during a roughly 11-year cycle. The sun reached the peak of activity, or solar maximum, in mid-2000.

After slowing down, the sun seemed to pick up its pace and entered a second peak phase by late 2001, NASA scientists said in February.

The announcement came days before NASA sent the High Energy Solar Spectroscopic Imager (HESSI) into orbit. The launch of the sun-watching spacecraft had been delayed for more than a year.

The $85 million satellite is equipped with a new kind of camera to create high-fidelity films of X-ray and gamma ray outbursts from the sun, the most powerful explosions in the solar system.

The Harvard team based its forecast on observations from the Solar and Heliospheric Observatory (SOHO) satellite of atomic particle speeds and temperatures in the sun's atmosphere.

The researchers caution that while the sun becomes calmer, it can still pack powerful punches. During the more tranquil phases, wind gusts from the sun's poles can migrate closer to the sun's equator and then drift in the Earth's direction.

"We will still need to be mindful of the approach of these high-speed wind streams and their associated high-energy electrons and magnetic disturbances that will still pose a threat to all of our [satellites]," the team's statement said.



 
 
 
 



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