CRACKLING SUNSPOT: Newly-numberd sunspot AR1538 is small but active. In an 18-hour period on July 30-31, it popped off more than 15 minor flares. Watch the sunspot crackle in this movie from NASA’s Solar Dynamics Observatory:
The nearly-constant flaring is a sign of tension in the sunspot’s magnetic field. It is not, however, a sure-fire sign that a major eruption is in the offing. On the contrary, a large number of minor flares might provide a degree of “magnetic relief” that makes a major eruption less likely.
The most likely source of a major flare today is sunspot AR1535, located more than 400,000 km north of crackling sunspot AR1538. AR1535 is relatively quiet but has a beta-gamma magnetic field that harbors energy for strong M-class eruptions.