July 21, 2012
Coronal Mass Ejection Unlikely To Reach Earth
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redOrbit Staff & Wire Reports - Your Universe Online
A coronal mass ejection (CME) associated with a solar flare emitted early Thursday morning is unlikely to reach Earth, but it could affect one of the two Solar Terrestrial Relations Observatory (STEREO) satellites currently orbiting the sun, NASA officials posted on the agency's official website.
According to the US space agency, the sun emitted a mid-level (M7.7) flare on July 19. The flare, which began at 1:13am EDT and peaked at 1:58am EDT, was said to be weaker than the largest (X-class) variety of flares. At their strongest, these gigantic radiation bursts can disrupt the atmosphere and impact GPS and telecom signals, but even M-class flares can cause brief radio communication blackouts at the North and South Poles, NASA said.
CMEs can also affect satellite and ground electronic systems when these solar particles reach Earth, which typically occur in one to three days. However, initial research models show that the ejection associated with Thursday's flares are not headed this way, but could have an effect on the STEREO-A spacecraft.
On Thursday, the NOAA's Space Weather Prediction Center (SWPC) reported, "Region 1520, now past the west limb, continues to erupt. It produced an R2 (moderate) Radio Blackout and a CME earlier today. Although not clearly Earth-directed, forecasters are analyzing it for tangential effects on the geomagnetic field. An S1 (minor) Solar Radiation Storm soon followed the eruption."
However, as of Friday evening, the SWPC forecast had been changed to the following: "A weak shock driven by recent CME activity from now-departed Region 1520, passed ACE around 0415 UTC (00:15 a.m. EDT) today. However, it caused no geomagnetic storm activity. The S1 (minor) Solar Radiation Storm persists, but should steadily decline through the day. Elsewhere, no significant activity occurred. Updates here should things change."
An increased amount of flare activity is to be expected, NASA said, due to the sun's standard 11-year cycle of activity. That cycle is nearing solar maximum, which is expected to occur sometime next year, and as such it is regular for there to be multiple flares each day now and in the foreseeable future, the US space agency added.