November 11, 2013
Sun Emitted X-class Solar Flare On Sunday
The sun emitted a significant solar flare that peaked at 1:14 a.m. EST on Nov. 10, 2013. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel.
To see how this event may impact Earth, please visit NOAA's Space Weather Prediction Center at http://spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings.
This flare is classified as an X1.1 class flare. "X-class" denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc.
Increased numbers of flares are quite common at the moment, since the sun's normal 11-year activity cycle is ramping up toward solar maximum conditions. Humans have tracked this solar cycle continuously since it was discovered in 1843, and it is normal for there to be many flares a day during the sun's peak activity. The first X-class flare of the current solar cycle occurred on February 15, 2011, and the largest X-class flare in this cycle was an X6.9 on August 9, 2011. This is the seventh significant flare since Oct. 23, 2013, with the largest being an X3.3 on Nov. 5, 2013.