Aurora.

An active region on the sun has spawned an M8.7 eruption – nearly an X-flare – that blasted a stream of charged particles toward Earth, due to arrive tomorrow (January 24, 2012). Experts at NOAA’s Space Weather Prediction Center are saying it is the strongest radiation storm since 2005. The eruption took place last night (January 22) at 9:59 p.m. according to clocks in the central U.S. (03:59 UTC on January 23). There is no danger to you on Earth’s surface, but satellites in orbit might feel the effects and your cell phone might act twitchier than usual. Plus … aurora alert at lower latitudes than normal!

Read the rest at EarthSky.