Solar storm sweeps over Earth

WASHINGTON: Space weather experts kept track of a solar storm that swept over our planet on Saturday, representing the fallout from a powerful solar flare earlier this week.
"The impact was not as strong as forecasters expected,"'s Tony Phillips wrote. "Nevertheless, the blow compressed Earth's magnetosphere and sparked a mild … geomagnetic storm."  
The solar storm originated from a massive solar flare on Thursday that included a powerful eruption on the sun, known as a coronal mass ejection, or CME. The eruption sent a wave of charged solar plasma toward Earth. The CME could amplify auroral displays, some space weather officials said.
Initial forecasts predicted the CME would arrive at Earth between 5 a.m. and 9 a.m. ET, with an error margin of plus or minus seven hours. The actual timing was on the late side: reported that the CME hit Earth's magnetic field at about 2 p.m. ET.
This weekend's solar storm originated from one of the most powerful sun flares to occur this year. The flare registered as an X1.4-class sun storm, one of the strongest flares the sun can unleash. It marked the sixth X-class solar flare of 2012.
The solar storm erupted from the giant sunspot AR1520, or Active Region 1520, which is actually a group of sunspots that at its peak may have stretched across 186,000 miles of the sun's surface, NASA scientists have said.
Auroral displays occur when charged solar particle interact with Earth's upper atmosphere. Usuallly, they are confined to high-latitude regions around the polar regions by the planet's magnetic field. Space weather forecasters said there was a chance that the auroral zone would be more extended on Saturday night.
The National Oceanic and Atmospheric Administration's Space Weather Prediction Center is tracking AR1520, as well as several other active spots on the sun, for signs of more activity. This weekend's solar storm was not expected to pose a major risk to satellites and spacecraft in orbit, or to power systems on Earth.
The sun is currently in the middle of an active phase in its 11-year sunspot cycle. The current cycle is known as Solar Cycle 24 and expected to peak in 2013.