Quiet Sunspot Wakes Up, Explodes

 
Source - Space Weather News for April 18, 2016: http://spaceweather.com

BIG SUNSPOT ERUPTS: Surprise! Quiet sunspot AR2529 isn't so quiet, after all. The heart-shaped active region erupted on April 18th (00:39 UT), producing a strong M6.7-class solar flare and shortwave radio blackouts around the Pacific. Visit http://spaceweather.com for more information.