The sun recently unleashed an "almost X-class" solar flare that was only fractionally less powerful than one of the sun's most powerful explosions. This flare has already bombarded us with radiation and unleashed a coronal mass ejection (CME) that will likely slam into Earth today (Nov. 30) or tomorrow (Dec. 1).

Solar flares are essentially large explosions that are triggered when magnetic fields around sunspots snap and fling plasma into space. On Nov. 28, a large flare erupted from a dark patch near the sun's equator. Solar orbiters measured the flare as a 9.8 magnitude M-class, which is just below the threshold of X-class flares — the most powerful class of solar flare, Spaceweather.com reported. (Solar flare classes include A, B, C, M and X, with each class being at least 10 times more powerful than the previous one. X-class flares are the equivalent of a magnitude 10 M-class flare and above.)