WAVES OF IONIZATION: Sunspot AR1515 is strobing Earth with C- and M-class solar flares. Each pulse of x-rays and extreme UV radiation creates a wave of ionization in our planet’s upper atmosphere. These sudden ionospheric disturbances, also known as “SIDs,” alter the propagation of radio signals around Earth. Yesterday, amateur scientist Roberto Battaiola detected a series of SIDs over Pantigliate, Italy:

“I monitored the radio frequency of 21.75 kHz,” he says.

More SIDs are in the offing as AR1515 continues to crackle with strong solar flares. In fact, a really big SID could occur if, as expected, AR1515 produces an X-class flare before it rotates off the solar disk a few days from now.

fr/spaceweather.com