Sun Unleashes X6.9 Class Flare on August 9, 2011

The X6.9 flare as seen by SDO/AIA in 13.1nm filter. The X6.9 flare as seen by SDO/AIA in 17.1nm filter. The X6.9 flare as seen by SDO/AIA in 19.3nm filter. The X6.9 flare as seen by SDO/AIA in 30.4nm filter. The X6.9 flare as seen by SDO/AIA in 33.5nm filter. On August 9, 2011 at 3:48 a.m. EDT, the sun emitted an Earth-directed X6.9 flare, as measured by the NOAA GOES satellite. These gigantic bursts of radiation cannot pass through Earth's atmosphere to harm humans on the ground, however they can disrupt the atmosphere and disrupt GPS and communications signals. In this case, it appears the flare is strong enough to potentially cause some radio communication blackouts. It also produced increased solar energetic proton radiation — enough to affect humans in space if they do not protect themselves.As of March 2014, this flare is the largest of solar cycle 24.Here are the raw images used in creating the components in Sun Unleashes X6.9 Class Flare on August 9, 2011 Related pages

Short narrated video about flares, how they are classified, and their effect on Earth.For complete transcript, click here. Frame from movie showing the flare classification scale. SDO AIA 304 image of February 15, 2011 X class flare. Short animation showing the many wavelengths of the sun provided by SDO. Flares happen when the powerful magnetic fields in and around the sun reconnect. They're usually associated with active regions, often seen as sun spots, where the magnetic fields are strongest. Flares are classified according to their strength. The smallest ones are B-class, followed by C, M and X, the largest. Similar to the Richter scale for earthquakes, each letter represents a ten-fold increase in energy output. So an X is 10 times an M and 100 times a C. Within each letter class, there is a finer scale from 1 to 9. C-class flares are too weak to noticeably affect Earth. M-class flares can cause brief radio blackouts at the poles and minor radiation storms that might endanger astronauts. Although X is the last letter, there are flares more than 10 times the power of an X1, so X-class flares can go higher than 9. The most powerful flare on record was in 2003, during the last solar maximum. It was so powerful that it overloaded the sensors measuring it. They cut-out at X17, and the flare was later estimated to be about X45. A powerful X-class flare like that can create long lasting radiation storms, which can harm satellites and even give airline passengers, flying near the poles, small radiation doses. X flares also have the potential to create global transmission problems and world-wide blackouts. Related pages