Sun emitted an X-class flare on Thursday at 8
NASA's Tony Phillips at Spaceweather.com said that the X1.3 flare caused a high-frequency radio wave blackout on the sun-facing side of the Earth shortly after the eruption, Discovery News reported.
X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc.
