FLYBY ALERT! Would you like a phone call when the International Space Station (ISS) is about to fly over your back yard? Sign up for Space Weather PHONE. | | | SATURN AND REGULUS: When the sun sets tonight, go outside and look south. You'll find a pair of starry eyes staring back at you. On the left is Saturn, on the right Regulus. The ringed planet and the first-magnitude star are only 2o apart--a pretty pair: sky map. SOLAR BLAST: No sunspots? No problem. On April 26th the blank sun unleashed a solar flare without the usual aid of a sunspot. At 1408 UT, Earth-orbiting satellites detected a surge of X-rays registering B3.8 on the Richter scale of solar flares. Shortly thereafter, SOHO coronagraphs recorded a coronal mass ejection (CME) billowing away from the sun: The expanding cloud could deliver a glancing blow to Earth's magnetic field late on April 28th or 29th. High-latitude sky watchers should be alert for auroras when it arrives. This strange solar flare came from a patch of sun (N08,E08) where magnetic fields were not intense enough to form a visible sunspot (sunspots are made of magnetism). Nevertheless, magnetic fields were present with sufficient energy and instability to produce a powerful explosion. NASA's twin STEREO spacecraft, observing the sun from widely separated vantage points, recorded a million mph shock wave or "solar tsunami" spreading from the blast site through the sun's atmosphere: movie. Not bad for a "blank sun." Stay tuned for updates. more images: from David Strange of Branscombe, Devon, UK; from Emiel Veldhuis of Zwolle, the Netherlands; from Stephen Ames of Hodegenville, KY; from Will Gater of Bristol, UK; from Patricia Cannaerts of Belgium; from Joel Bavais of Anvaing, Belgium; IRIDIUM FLARES 24-7: Anyone who's ever seen an Iridium satellite flaring in the night sky knows what it must be like to witness a supernova. Sudden. Breath-taking. Unforgettable. At the South Pole, the unforgettable happens 160 times a day. R. Dana Hrubes sends this report from the Amundsen-Scott South Pole Station where all six orbital planes of the polar orbiting Iridium satellites cross: "The sun has set here for 6 months and we get Iridium flares every 9 minutes and 8 seconds for 4 to 5 days at a time." Indeed, such a "flare session" is underway now. This April 28th self-portrait shows Hrubes with a flare in the background near the Southern Cross. The brilliant flash of light occurred when sunlight glinted off one of the satellite's flat surfaces. "I took this picture and three others using my Canon Rebel XTI 400D," says Hrubes. "The brightest magnitude -8 flares occur every 9 min for an entire day! We routinely use the Iridium satellites for communication from the Pole." |