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This intense period of solar activity isn't unexpected; it's all part of the natural solar cycle that ebbs and flows over an approximate 11-year cycle. The peak of this cycle, called "solar maximum," is expected in 2013, but in the run-up to the crescendo, the sun has been increasingly active.Solar max represents a period when the sun's magnetic field is at its most stressed, so magnetic features like coronal loops and prominences are often observed in the sun's atmosphere (the corona). Explosive events like CMEs and flares also become commonplace. The solar wind -- a stream of charged particles that constantly flow into interplanetary space -- also becomes amplified.All of these factors can impact our planet's magnetic field, increasing the chances of radiation and geomagnetic storms -- magical light shows in the form of aurorae are often a result of this geomagnetic battle. Solar storms can also impact our increasingly high-tech society, a fact not lost on the world's space weather prediction efforts.source: http://news.discovery.com/space/will-the-sun-unleash-a-thanksgiving-flare-121121.html
Fire in the Sky
Scientists warn of a solar flare large enough to paralyze our electrified world
By Joan Trossman Bien 11/21/2012If you have never heard of an electromagnetic pulse, or EMP, then you have not spent any time worrying about an EMP causing the end of civilization as we know it. But scientists and some policymakers worry about such a thing happening, and for very good reason. If an EMP were to occur over the United States, caused either by a particularly violent solar storm or by a small nuclear device detonated many miles above the ground, chances are high that the country’s entire electrical grid would fail, as a massive surge of electricity would fry the huge transformers that keep the grid humming. Satellites we rely on for navigation and communication would be damaged beyond repair, and society would crumble into a dysfunctional scramble for survival. The very necessities of life, such as clean water, food, medications, transportation, even government, would all either disappear or be in very short supply. There are sharp differences of opinion among experts regarding the likelihood of an EMP occurring anytime soon. But, nuclear attack aside, given the fact that extreme solar events happen once or twice a decade, “It is just a question of not if, but when the Earth happens to be in the path of these kinds of [solar] storms,” according to Dan Baker, director of Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado.Big changesWhat exactly is a solar flare and why should anyone care? Marco Velli, a senior researcher at NASA’s Jet Propulsion Laboratory whose expertise is in solar research, has been named principal investigator for NASA’s Solar Probe Plus, scheduled to launch in 2018. The project will place a satellite into orbit around the sun — inside its corona, far closer than ever before — as part of a mission to study solar weather. “A solar flare is essentially an explosion,” Velli explained, adding that it sends out a huge amount of plasma or high-energy gas from the sun called coronal mass ejections (CMEs). “The energy is equivalent to several thousand atomic bombs … accelerating high energy particles to very high speeds, like cosmic rays.” The potential damage, Velli added, depends on where the blast actually hits. “When one of these big CMEs takes off and is directed toward Earth, it can cause big changes in the Earth’s magnetic field. This can induce currents in the Earth’s ionosphere and also in things on the ground, like big power stations, and it can disrupt the grid. It is the kind of thing that can fry the transformers so they cannot be used again. That’s bad,” he said. Dr. Edwin Krupp, director of the Griffith Observatory in Griffith Park, put this fairly common event of solar flares into perspective. “For thousands of years, the only impact was the display of the aurora borealis. It didn’t have much of an influence on life on Earth until the era of high technology,” Krupp said. Baker described how our lives have changed so quickly. “I like to say that modern humans have embedded us within a cyber-electric cocoon that surrounds the entire Earth. In many ways, every one of our modern technologies can be affected by solar storms,” he said. Experts agree that the most damaging aspects of a solar storm are large CMEs, which, Baker said, “are very large blobs of material that are expelled from the sun and can be huge in dimension. It is often noted that the largest of these can be moving at many millions of miles an hour.” Explaining how CMEs damage electronics, Baker said, “When one of these big CMEs takes off, when it is directed towards the Earth, it can cause big changes in the Earth’s magnetic field. It can charge up the Earth’s magnetosphere with strong, high-energy particles as well. This can induce currents in the Earth’s ionosphere and also in things on the ground, like big power stations, and it can disrupt the grid.”
Solar superstormThe Big Daddy of modern solar storms, called the Carrington Event for well-known British amateur astronomer Richard Carrington, occurred on Sept. 1, 1859. At the time, Carrington was just setting up his London solar observatory to chart an active solar storm. The telescope aimed at the sun projected an image that Carrington could trace on paper. As he was drawing the sunspots, according to modern-day accounts from a number of Web sites covering the subject, “two patches of intensely bright and white light” appeared on his screen. They were located in one large group of sunspots. Carrington left the room to notify another scientist, but by the time he returned about five minutes later, the event had ended. Another amateur astronomer, Roger Hodgson, also observed the phenomenon. Over at Kew Observatory in London, a magnetometer needle dangled from a thread. It began to flail and bounce. They had just observed the beginnings of a solar super storm.
Before dawn the next morning, the skies went psychedelic with auroras as far south as Hawaii and Panama. Bright swirls of reds, greens and purples lit up the still-dark early morning skies. Baker reported at a geophysics meeting in 2010 that the light was so bright, “people in the northeastern US could read newspaper print just from the light of the aurora.” The Charleston Mercury ran a first-person account from a woman on Sullivan’s Island in South Carolina. “The eastern sky appeared of a blood red color,” she wrote. “It seemed brightest exactly in the east, as though the full moon, or rather the sun, was about to rise. It extended almost to the zenith. The whole island was illuminated. The sea reflected the phenomenon, and no one could look at it without thinking of the passage in the Bible, which says, ‘the sea was turned to blood.’ The shells on the beach, reflecting light, resembled coals of fire.” The New York Times reported that people stood on rooftops and gathered on sidewalks to watch “the heavens … arrayed in a drapery more gorgeous than they had been for years.” The most sophisticated mode of communication at the time was the telegraph, and when the supercharged CME hit the Earth’s magnetic field, telegraph wires surged with the electrical currents. It blew out the machines at some places. At others, the sparks caused fires. When operators turned off their batteries, the telegraph machines continued to work. The Carrington Event was extraordinarily huge. Ice core samples have revealed it was double the size of any other solar storm in the preceding 500 years. And scientists say it will happen again, possibly soon.Dodging bulletsSolar flares are not unusual. On March 13, 1989, a CME blew out power in Quebec, leaving 6 million people in the dark. In 1921, a solar storm hit, but didn’t cause much damage. Today, such an occurrence would have darkened half of North America. Last summer, Baker said there was a very close call. “Just on July 22, there was a very ugly, mean-looking active region on the sun that had moved across the face of the sun. A satellite was watching it. A huge flare, and then a CME, came at the spacecraft and it was moving at the highest recorded speed that has been seen in the modern Space Age. It reached the satellite in 17 hours. That’s an hour faster than the Carrington Event, and it led to extremely intense magnetic fields in the interplanetary medium. For all intents and purposes, that was a Carrington Event that just missed us. We dodged the proverbial bullet there. Now we know there have been others like this.” Can it happen again? “Some people say that the Carrington Event is a moldy old event and these things happen only once in 1,000 years,” Baker said. “I think recent work has suggested quite the contrary. The probability of any of these occurring during one 11-year cycle of solar storms is like 10 percent, a pretty significant probability. It’s not a rare thing.” Ultimately, whether triggered by a rogue nation’s high-altitude detonation of a small nuclear weapon or set off by a rare but possible extremely strong solar flare, the result will be the same if we continue to do nothing.
A perfect solar stormNot all experts agree with Baker about the chances of a Carrington Event-type of CME causing the lights to go out. In fact, there has been some recent commentary about the analysis of solar flares that have occurred over the past 50 years. Solar storms occur in cycles of about 11 years. We are now entering what has been described as a very active part of the 11 year cycle. It is called the solar maximum, and the scientific community believes that it could be quite potent.Baker described a worst-case scenario: “When these huge clouds of material move out at such high speeds, a powerful shockwave can form in front of them. The CMEs can also have embedded within them much stronger magnetic fields, and this entire cloud can, in turn, lead to the acceleration of charged particles. It is sort of the perfect solar storm that’s headed directly at Earth. Those currents get coupled into very long power lines on a continental scale, the power grid. That is the one thing that we worry about most from solar storms — the effect these CMEs can have on the power grid.” read much more at http://www.pasadenaweekly.com/cms/story/detail/fire_in_the_sky/11673/
M-CLASS SOLAR FLARES: The magnetic canopy of big sunspot AR1618 is crackling with M-class solar flares. This image taken by NASA's Solar Dynamics Observatory shows the extreme ultraviolet flash from one of them, an M1.6-class flare on Nov. 20th at 1928 UT:
This eruption, and another one like it about 7 hours earlier, might have propelled faint coronal mass ejections (CMEs) toward Earth. If so, the impacts would likely commence on Nov. 23rd, with a chance of high-latitude geomagnetic storms following their arrival. Stay tuned for updates. Aurora alerts: text, voice.FAST-GROWING SUNSPOT (Updated Nov. 21): Only a few days ago, sunspot AR1618 was almost invisible. Now it is a behemoth more than 10 times wider than Earth. A movie from NASA's Solar Dynamics Observatory shows the sunspot's development on Nov. 20-21:
As the sunspot evolves, so does its intense magnetic field--and this means strong flares are in the offing. Fast-changing magnetic fields on the sun have a tendency toreconnect and erupt. NOAA forecasters estimate a 70% chance of M-class flares and a 15% chance of X-flares during the next 24 hours. Because of the sunspot's nearly central location on the solar disk, any eruptions will likely be Earth-directed.Solar flare alerts: text, voice.
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| SPACE WEATHERNOAA Forecasts |  |
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| FLARE | 0-24 hr | 24-48 hr |
| CLASS M | 70 % | 70 % |
| CLASS X | 30 % | 30 % |
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source: http://spaceweather.com/  source: http://www.swpc.noaa.gov/ Double Prominence Eruptions The Sun erupted with two prominence eruptions, one after the other over a four-hour period (Nov. 16, 2012). The action was captured in the 304 Angstrom wavelength of extreme ultraviolet light. It seems possible that the disruption to the Sun's magnetic field might have triggered the second event since they were in relatively close proximity to each other. The expanding particle clouds heading into space do not appear to be Earth-directed.source: http://sdo.gsfc.nasa.gov/gallery/potw.php?v=item&id=121 |
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