The following is from http://www.foxnews.com/science/2013/07/04/sun-unleashes-solar-fireworks-for-july-fourth:
The sun fired off an intense solar flare Wednesday, giving NASA scientists a solar preview to the Fourth of July holiday in the United States.
The solar flare erupted at about 3 a.m. EDT (0700 GMT) and was spotted by NASA’s Solar Dynamics Observatory, which snapped a photo of the July solar storm.
“Just a few minutes after 7:00 UT, the sun produced an M1.5-class solar flare. Perhaps an early Fourth of July fireworks?” SDO mission officials wrote in a Facebook post announcing the flare.
M-class solar flares are medium-strength solar storms that can supercharge Earth’s northern lights displays when they are aimed at Earth. NASA officials reported that the July 3 solar flare erupted from a point just over the eastern side, or limb, of the sun, so it was not directed at our planet.
The most powerful type of solar flares are X-class sun storms. When aimed directly at Earth, X-class flares can pose a threat to astronauts in space, interfere with satellite signals and potentially affect electrical power grids on Earth….