EMERGING BLAST SITE: A farside sunspot that exploded and hurled a bright CME into space on Sept. 23rd is now rotating onto the Earthside of the sun. NASA’s Solar Dynamics Observatory photographed the emerging blast site during the early hours of Sept. 26th:
Because the sunspot is still near the sun’s eastern horizon, foreshortening prevents a clear view of its core magnetic structure. The events of Sept. 23rd, however, suggest that this could be a potent active region. Stay tuned for updates as the sunspot turns toward Earth
CRACKLING SUNSPOT: Newly-numberd sunspot AR1538 is small but active. In an 18-hour period on July 30-31, it popped off more than 15 minor flares. Watch the sunspot crackle in this movie from NASA’s Solar Dynamics Observatory:
The nearly-constant flaring is a sign of tension in the sunspot’s magnetic field. It is not, however, a sure-fire sign that a major eruption is in the offing. On the contrary, a large number of minor flares might provide a degree of “magnetic relief” that makes a major eruption less likely.
The most likely source of a major flare today is sunspot AR1535, located more than 400,000 km north of crackling sunspot AR1538. AR1535 is relatively quiet but has a beta-gamma magnetic field that harbors energy for strong M-class eruptions.
SOLAR ACTIVITY PICKS UP: Sunspot AR1532 is crackling with M-class solar flares. The latest, an M6-class eruption on July 28th (2056 UT), produced a bright flash of extreme ultraviolet radiation, shown here in a snapshot from the Solar Dynamics Observatory:
Update: Contrary to earlier reports, this explosion did produce a CME and the cloud is heading for Earth. According to a forecast track prepared by analysts at the Goddard Space Weather Lab, the CME will reach our planet on July 31st at 1500 UT (+/- 7 hours). Weak to moderate geomagnetic storms are possible when the cloud arrives.
ALMOST X-FLARE : Sunspot complex AR1520-1521 erupted again on July 19th, this time producing an M7-class solar flare that almost crossed the threshold into X-territory. NASA’s Solar Dynamics Observatory recorded the extreme ultraviolet flash:
The explosion produced a bright coronal mass ejection. The cloud should miss Earth.
Although the explosion occured on the other side of the sun’s western limb, our planet could feel some effects. The blast site is magnetically connected to Earth by backward-spiralling lines of magnetic force. Protons accelerated by the flare are being guided to us by those lines of magnetism, and a mild radiation storm is underway.
4TH OF JULY FIREWORKS: Chances of an X-flare today are increasing as sunspot AR1515 develops a ‘beta-gamma-delta’ magnetic field that harbors energy for the most powerful explosions. The sunspot’s magnetic canopy is crackling with almost-X class flares, the strongest so far being an M5-flare at 09:54 UT. Each “crackle” releases more energy than a billion atomic bombs, so these are 4th of July fireworks indeed.
The sunspot itself is huge, stretching more than 100,000 km (8 Earth-diameters) from end to end. This movie from NASA’s Solar Dynamics Observatory shows the behemoth growing and turning toward Earth over the past five days:
Another picture that dramatically illustrates the size of AR1515 is this 4th of July sunrise shot from Stefano De Rosa of Turin, Italy.
If any major eruptions do occur today, they will certainly be Earth-directed. The sunspot is directly facing our planet, so it is in position to cause radio blackouts, sudden ionospheric disturbances, and geomagnetic storms.
CHANCE OF FLARES: Sunspot AR1504 has a complex ‘beta-gamma’ magnetic field that harbors energy for strong solar flares–and the huge sunspot is almost directly facing Earth. Amateur astronomer Eric von der Heyden photographed the behemoth on June 16th from his backyard observatory in Mühltal-Traisa, Germany:
Each of the dark cores in the image is about twice the size of Earth. The sheer size of the complex makes it an easy target for backyard solar telescopes.
NOAA forecasters estimate a 65% chance of M-flares and a 5% chance of X-flares from AR1504 during the next 24 hours
SOLAR ACTIVITY INTENSIFIES: Huge sunspot AR1476 is crackling with M-class solar flares and appears to be on the verge of producing something even stronger. The sunspot’s ‘beta-gamma-delta’ magnetic field harbors energy for X-class flares, the most powerful kind. Earth is entering the line of fire as the sunspot rotates across the face of the sun. Solar flare alerts:text, phone.
Earlier today, amateur astronomer Thomas Ashcraft of New Mexico detected strong shortwave radio bursts coming from the sunspot. Click to hear the “solar static” that roared out of his loudspeaker:
Dynamic spectrum courtesy of Wes Greenman, Alachua Radio Observatory
“The strongest burst so far occured around 1631 UT on May 9th,” reports Ashcraft. “I am observing at 28 MHz and 21.1 MHz. As I send this note I am hearing more bursting, indicating powerful magnetic dynamism within active region 1476.”
Solar radio bursts are caused by plasma instabilities that ripple through the sun’s atmosphere in the aftermath of powerful flares. With AR1476 poised for more eruptions, this ‘radio activity’ is likely to continue for days
They say the Sun is becoming less active. Let’s check the record of days without Sunspots from 2009: Spotless Days Current Stretch: 0 days
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
SUNSPOT GENESIS: The solar disk is peppered with sunspots and at least three of them are crackling with C-class solar flares. Make that four. A new sunspot, AR1465, has just broken through the stellar surface to join the action. Cai-Uso Wohler photographed the emergence from his backyard observatory in Bispingen, Germany:
NOAA forecasters estimate a 30% chance of an M-class flare during the next 24 hours. As the youngest and least stable of the sunspots, AR1465 is the most likely source. Stay tuned for solar activity
GROWING SUNSPOT: What a difference a day makes. On April 16th, sunspot AR1460 did not exist. Twenty-four hours later it was twice as big as the planet Earth. This April 17th movie from NASA’s Solar Dynamics Observatory shows sunspot genesis in action:
The sunspot’s magnetic field is still too simple for strong flares, but if the expansion continues apace, instabilities could develop that lead to explosions. Readers with solar telescopes should keep an eye on AR1460.
