Gargantuan sunspot 15-Earths wide shoots powerful X-class flare toward Earth, triggering radio blackouts

AR3664 is no ordinary sunspot. 

The behemoth dark patch on the sun's surface has ballooned in recent days, becoming one of the largest and most active sunspots seen this solar cycle. 

AR3664 garnered the attention of scientists earlier this week as the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center issued a warning of increased solar flare risk from the solar giant on Tuesday (May 7).

"Region 3664 has grown considerably and has become much more magnetically complex," NOAA's SWPC reports. "This has led to increased solar flare probabilities over the next several days." 

The giant sunspot has more than lived up to expectations. Firing out countless powerful solar flares in recent days, including a colossal X-class solar flare this morning (May 9), peaking at 5:13 a.m. EDT (0913 GMT).

Related: What if the Carrington Event, the largest solar storm ever recorded, happened today?

Solar flares are eruptions from the sun's surface that emit intense bursts of electromagnetic radiation. They are categorized by size into lettered groups, with X-class being the most powerful. Then there are M-class flares that are 10 times less powerful than X-class flares, followed by C-class flares which are 10 times weaker than M-class flares, B-class are 10 times weaker than C-class flares and finally, A-class flares, which are 10 times weaker than B-class flares and have no noticeable consequences on Earth. Within each class, numbers from 1-10 (and beyond for X-class flares) describe a flare's relative strength.