A fast-erupting sunspot just hurled out a huge flare.

The hotbed of sun activity, known officially as AR2975, sent out a powerful X-class flare that has already created a temporary blackout in shortwave radio signals in the Americas, according to SpaceWeather.com. (AR2975 has already burped more than 17 moderate-sized flares in recent days, but this outburst is a bit more powerful.)