CME eruption in upper left corner. The bright speck of light to the right is Mercury. (Image credit: SOHO LASCO C3)

The M5.7 solar flare triggered radio blackouts on the sunlit portion of Earth at the time of the eruption. (Image credit: NOAA Space Weather Prediction Center)

Solar flares are ranked using a scale A, B, C, M and X — the latter being the most powerful category. Each step represents a tenfold increase in energy output. The May 10 event reached M5.7 strength, making it a powerful flare capable of disrupting radio communications on Earth.

The solar flare eruption triggered a radio blackout over the Atlantic Ocean, according to NOAA's Space Weather Prediction Center. These blackouts occur when intense X-ray and ultraviolet radiation from solar flares ionize Earth's upper atmosphere, interfering with high-frequency radio signals used by aviators, mariners and amateur radio operators.

CME eruption on May 10.…