On September 5, 2011, the sun emitted an Earth-directed M5.3 class flare as measured by the GOES satellite. The flare erupted from a region of the sun that appears close to dead center from Earth's perspective, an active region designated number 1283. The flare caused a slight increase of solar energetic protons some 26,000 miles above Earth's surface.
A coronal mass ejection (CME) - another solar phenomenon that can send solar particles into space - was associated with this flare. The CME is a relatively slow one, traveling at under 200 miles per second.
Because of the sunspot's central location on the solar disk, the eruption was Earth-directed-but is a CME heading our way? Around the time of the explosion, a number of plasma clouds were already billowing away from the sun, adding an element of confusion to the analysis. Tentatively, we expect Earth's magnetic field to receive a glancing blow from a CME on Sept. 8th or 9th. Stay tuned for updates.