Gigantic Sunspot Unleashes Flare; Expect Aurorae Tonight!

Right now, the Sun is sporting a huge sunspot called AR1944. It's grown in size over the past few days to a staggering 200,000 kilometers (125,000 miles) across. As I wrote the other day, sunspots are regions of intense magnetism, and these magnetic fields store huge energies. They can be unleashed in vast explosions called solar flares... and AR1944 popped off a good one on Jan. 7. The image above shows the Sun in ultraviolet by NASA's Solar Dynamics Observatory, taken on Jan. 7 at 18:33 UTC, j...