(The SDO observations have revealed a set of flares that have a large second peak for some of the extreme ultraviolet (EUV) emissions. It had previously been known that the EUV emissions have a peak near the time of the flare’s X-ray peak, but this second EUV peak is one to five hours later and without a corresponding X-ray peak. We refer to this delayed, second peak as the EUV Late Phase. CREDIT: NASA/University of Colorado/Tom Woods)
“For roughly the last 50 years, solar flares have been categorized and detected by the x-rays they give off. The current classification of flares goes, in increasing power at their peak, A, B, C, M, X.”
“Last Wednesday, scientists reported that they haven’t been noticing most of the solar flares’ energy. In a NASA Press Conference, held simultaneously with the release of a paper online in The Astrophysical Journal, they reported on new results based on observations with NASA’s Solar Dynamics Observatory.”
“Several analyses have now shown that at least a group of the most powerful flares, which are detected in x-rays by satellites such as the GOES (Geostationary Operational Environmental Satellite) series of the National Oceanic and Atmospheric Administration, give off more energy about 90 minutes later than the x-ray peak than occurred in that first detected peak.”
There may be more to solar flares than meets the eye, not only in the energy output of these events but in their impact on the geomagnetic environment of the Earth. It has long been known that Earth-orbiting satellites are vulnerable to the the streams of charged particles emitted by flares, as are ground-based radio and electrical networks. The extended emission in flares recently discovered may even have an adverse effect on the Global Positioning System, or GPS, constellation of satellites, on which everything from ships at sea to commercial airliners depend for reliable, world-wide navigation. There is also an economic impact involved: costs due to damage of the communications infrastructure caused by solar magnetic activity could run into the hundreds of billions. As we enter the upcoming “solar max”, the problem becomes more acute with each passing day.
Astronomy news, recent research results, and pretty pictures from the media along with context, commentary, and explanations for folks who dig this sort of thing. Written by a quasi-professional astronomer affiliated with the University of Texas at Austin.