The past 48 hours has been busy for our sun. The closest star to Earth has hurled a total of four major X-class solar flares into the depths of space as activity amps up for the end of the 2013 solar cycle peak. Four images from NASA's Solar Dynamics Observatory of an X3.2-class flare from late at night on May 13, 2013. (Photo : NASA/SDO)
The past 48 hours has been busy for our sun. The closest star to Earth has hurled a total of four X-class solar flares into the depths of space as activity amps up for the peak of the 11-year solar cycle in 2013.
Solar flares are powerful bursts of radiation that can sling the harmful material through space toward Earth. Fortunately, this radiation cannot pass through our atmosphere to impact humans on the ground. However, it can sometimes disturb the atmosphere enough so that it disrupts radio signals.
Like hurricanes, solar flares are classified based on their intensity. The weakest are known as A-class flares, followed by B, then C and M. The strongest solar flares are labeled X-class flares, and can pose a risk to astronauts and satellites in orbit when aimed directly at Earth. In order to categorize the strength of these flares within their classes, though, researchers also give them numbers. The higher the number, the stronger the flare is.
The first flare occurred on Mother's Day, May 13. A comparatively demure X1.7 flare, it was associated with a coronal mass ejection (CME). This solar phenomenon can send billions of tons of solar particles into space that can reach other planetary bodies days after the initial burst. When directed toward Earth, these CMEs can disrupt satellites and can supercharge the northern lights, creating spectacular displays. In fact, a solar flare that occurred in April did just that, sparking a geomagnetic storm that produced an impressive light show.
The second solar flare that the sun flung into space was a stronger X2.8-class flare, which was also associated with a CME. Experimental NASA models showed that solar particles sped from the sun at a terrific 1,200 miles per second. It was the strongest flare to have occurred all year--until the third flare came along.
The third solar flare occurred on the evening on May 13 and was classified as a X3.2 flare. It's the strongest to have occurred all year and also hurled a CME into space. Fortunately for us, none of these CMEs are Earth-directed, which means that they won't be causing issues with satellites.
The sun wasn't done yet, though. It ejected its fourth and final solar flare in the early morning hours of May 15. The X1-class flare was comparatively tiny to the other ones that the sun had belched out, but it shows that our star is currently more active than it has been in a long while. In fact, NOAA forecasters estimate a 50 percent chance of X-class solar flares and an 80 percent chance of M-class solar flares on May 15, according to spaceweather.com.
"These are spectacular events," said Robert Massey from the UK's Royal Astronomical Society in an interview with BBC News. "An X-class flare is equivalent to a billion hydrogen bombs. We're talking about a colossal amount of energy."
Until the sun reaches its solar peak at the end of 2013, though, we're likely to continue to see these spectacular events into the near future.
Check out the video of the flares, courtesy of NASA.
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