BIG SUNSPOT FACES EARTH: In a year of few sunspots, AR2645 is remarkable. The young spot has quickly grown from an almost invisible speck into a sprawling behemoth more than 120,000 km wide, with multiple dark cores larger than Earth. And, it is directly facing our planet:
AR2645 has a 'beta-gamma' magnetic field that harbors energy for M-class (moderately strong) solar flares. Any such explosions while the sunspot faces Earth could ionize the top of our planet's atmosphere and alter the normal propagation of radio transmissions around the globe. Shortwave radio blackouts are possible if the sunspot erupts.
Despite its potential, AR2645 has so far been quiet, emitting only a crackling of minor C-flares with minimum effect on Earth. NOAA forecasters estimate a 10% chance of more potent M-flares in the next 24 hours.
"Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams."
SIGNIFICANT SOLAR FLARE: Sunspot AR2644 erupted on April 1st, producing a significant M4-class solar flare. NASA's Solar Dynamics Observatory recorded the explosion's extreme UV flash.
UV radiation from the flare caused a brief shortwave radio blackout on the Pacific side of Earth: map. People who might have noticed the blackout include ham radio operators and mariners using low-frequency rigs for communication at frequencies below 10 MHz. The explosion also hurled a coronal mass ejection (CME) into space: image. The cloud is not heading directly for Earth, but a glancing blow is possible in the days ahead. NOAA analysts are evaluating this possibility now. NOTE: The source of this flare, AR2644, is not the big sunspot discussed below. While forecasters focused their attention on the huge sunspot facing Earth, a lesser sunspot near the sun's western limb exploded instead. Tricky sun.
It will be interesting to see soon whether or not AR 2644 or 45 will re-emerge from the Eastern limb.
The sun has been spotless for a few now.
Like this ?
ACTIVE SUNSPOT RETURNS: During the late hours of April 17th, something hurled a plume of hot gas over the eastern limb of the sun. NASA's Solar Dynamics Observatory photographed the splash:
The source of this activity is probably returning sunspot AR2644. In early April the active region produced a series of M-class solar flares and shortwave radio blackouts. Now, following a two week trip around the farside of the sun, AR2644 is due to return. Amateur astronomers with solar telescopes are encouraged to monitor the sun's eastern limb for signs of the old sunspot. If it returns with any of its old potency, solar flare activity could increase sharply in the days ahead.
Re: Solar Superstorms
« Reply #118 on: Apr 19th, 2017, 08:15am »
SPECTACULAR CME :
Old sunspot AR2644 has returned--and it is still active. On April 18th at approximately 2000 UT, the sunspot's magnetic canopy exploded and hurled a bright coronal mass ejection (CME) into space. The ESA/NASA Solar and Heliophysics Observatory caught the cloud as it raced away from the sun:
This CME will probably miss Earth. The explosion's epicenter was too far off the Sun-Earth line for a direct hit. NOAA analysts are still evaluating the possibility of a glancing blow, however, so stay tuned for updates.
More CMEs may be in the offing. In early April this sunspot produced a series of strong M-class flares and shortwave radio blackouts on Earth. Geoeffective activity stopped only when the sunspot went into hiding on the farside of the sun. Two weeks later it's back--and so are the explosions.
Note: By longstanding tradition, sunspots that travel around the backside of the sun and re-appear are renumbered. AR2644 therefore has a new designation: AR2651.
Re: Solar Superstorms
« Reply #119 on: Apr 22nd, 2017, 3:36pm »
I wasn't surprised, were you Cleef ?
SURPRISE! EARTH DAY AURORA STORM: Last night, Northern Lights descended into the United States as far south as Michigan, Minnesota, and Washington, kicking off an unexpected display of bright auroras for Earth Day. Both ends of our planet started to glow as the magnetic storms intensified. Cindy Ballantyne sends this picture from the Otago Peninsula in New Zealand:
What happened? A bright CME that left the sun on April 19th was supposed to miss Earth. Instead, it hit, delivering a glancing blow that surprised forecasters.
The show's not over. G1 and G2-class geomagnetic storms are underway on April 22nd as Earth moves through the CME's magnetized wake. High-latitude sky watchers should remain alert for midnight auroras on April 22-23. Free: Aurora Alerts