The July 2012 Solar Superstorm Near-Miss

What happened

One of the fastest and most intense CMEs ever recorded erupted from the far side of the Sun on July 23, 2012, crossing the Sun-Earth distance in roughly 17 hours. It struck NASA's STEREO-A spacecraft, which measured a magnetic field and speed comparable to or greater than the 1859 Carrington Event. A widely cited NASA analysis concluded that had it left the Sun nine days earlier, Earth would have taken a direct hit with potentially catastrophic consequences for the global power grid.