LOTS OF SOLAR FLARES: Solar activity is high. During the past 48 hours, monster sunspot AR2192 has produced a series of seven
M-class solar flares of increasing intensity. The eruptions crossed the threshold into
X-territory with an X1-class flare on Oct. 22nd. NASA's Solar Dynamics Observatory recorded a powerful flash of extreme UV radiation in the sunspot's magnetic canopy at 14:30 UT:
Remarkably, not one of the explosions so far has hurled a significant CME toward Earth.
The primary effect of the flares has been to ionize Earth's upper atmosphere, causing a series of short-lived HF radio communications blackouts. Such blackouts may be noticed by amateur radio operators, aviators, and mariners.
Earth-effects could increase in the days ahead. AR2192 has an unstable 'beta-gamma-delta' magnetic field that harbors energy for powerful explosions, and the active region is turning toward Earth. NOAA forecasters estimate at 65% chance of M-class flares and a 20% chance of X-flares during the next 24 hours.
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AR2192 is shaping up to be the biggest sunspot in many years. Its area is now approaching that of AR0486, the last great sunspot of the previous solar cycle, which covered 2610 millionths of the solar disc on
Oct. 30, 2003. As of 0h UT today AR 2192 is 2410 millionths. (Thanks to Geoff Chester of the US Naval Observatory for this comparison.)
Because the sunspot is so large--now about as wide as the planet Jupiter--people are beginning to notice it at sunset when the sun is dimmed by clouds or haze. Pilot Brian Whittaker took this picture on Oct. 21st while flying 36,000 ft over Resolute, Nunavut, Canada:
