Sunspot AR1748 unleashed an M3-class solar flare on May 17th at 0858 UT: image. Although this is not the strongest flare we’ve seen from AR1748, it could be the most geoeffective. The sunspot is facing Earth more directly than before, and the explosion might have hurled a CME toward our planet. Stay tuned for updates. Solar flare alerts: text, voice.
To illustrate the scale of the sunspot, photographer Göran Strand of Frösön, Sweden, inserted Earth into a picture of AR1748 he took on May 16th: