NASA GSFC | Karen C. Fox/Susan Hendrix | 2011 Aug 09
On August 9, 2011 at 3:48 a.m. EDT, the sun emitted an Earth-directed X6.9 flare, as measured by the NOAA GOES satellite. These gigantic bursts of radiation cannot pass through Earth's atmosphere to harm humans on the ground, however they can disrupt the atmosphere and disrupt GPS and communications signals. In this case, it appears the flare is strong enough to potentially cause some radio communication blackouts. It also produced increased solar energetic proton radiation -- enough to affect humans in space if they do not protect themselves.
There was also a coronal mass ejection (CME) associated with this flare. CMEs are another solar phenomenon that can send solar particles into space and affect electronic systems in satellites and on Earth. However, this CME is not traveling toward and Earth so no Earth-bound effects are expected.
Updates will be forthcoming if needed.
Related Links:
› Solar Flares: What does it take to be X-class?
› Spaceweather: Frequently Asked Questions
› Video: Sun Unleashes X-Class Flare
Sun Erupts with Largest Solar Flare of the Cycle
Universe Today | Nancy Atkinson | 2011 Aug 09
Early Tuesday morning (August 9, 2011,) the Sun erupted with the largest solar flare of Cycle 24, registering as an X7-class flare. This flare had an X-ray magnitude of X6.9, meaning it was more than 3 times larger than the previous largest flare of this solar cycle – the X2.2 that occurred on Feb 15, 2011, NASA said. The source was Sunspot 1263 which is nearing the western limb of the Sun, and because of its location, scientists do not anticipate that this explosion will hit Earth directly. Therefore, the impact on communications and electric grids will likely (and luckily) be minimal.Click to play embedded YouTube video.Click to play embedded YouTube video.
A solar flare is an explosion on the Sun that happens when energy stored in twisted magnetic fields –usually above sunspots — is suddenly released. Flares produce a burst of radiation across the electromagnetic spectrum, from radio waves to x-rays and gamma-rays.
Solar flares are classified according to their x-ray brightness, and there are 3 categories: X-class flares are big and are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth’s polar regions. Minor radiation storms sometimes follow an M-class flare. Compared to X- and M-class events, C-class flares are small with little noticeable impact on Earth.
You can see more about the size of solar flares here.
See more about today’s flare from Solar Watch and the Solar Dynamics Observatory.
For more information see SpaceWeather.com and the Solar Dynamics Observatory website.
Another big solar flare
Discover Blogs | Bad Astronomy | 2011 Aug 09
At 03:48 UT on August 9 (earlier today as I write this), the Sun blasted out another flare, the largest of the cycle so far. It was seen by the orbiting Solar Dynamics Observatory:
This image shows the Sun in the far ultraviolet; sunspots appear bright at this wavelength and the flare is pretty obvious! It came from a sunspot that is near the Sun’s limb. Since it was so far to the side it’s unlikely to do us much harm here on the Earth’s surface, though there may be some satellite communication issues. It also blew out a storm of subatomic particles, which might potentially harm astronauts in space. I haven’t heard yet if the crew on the space station will need to seek shelter deeper inside the structure (they’ve had to do that before in solar events, but there’s never been any case of diagnosed harm).
SDO also captured pretty dramatic video of the event:
This was an X6.9 flare, which is pretty big, but still not like the ones we saw in late 2003 which were far more powerful. Still, this is the biggest flare from the new solar cycle, and I think the first flare from this particular sunspot, named Active Region 1263. Last week, AR 1261 blew out several flares, but none as big as this one.
By coincidence I was at Big Bear Solar Observatory in California just two days ago, and saw AR 1263 roiling on the Sun’s surface. 1261 was already about to slip behind to the far side of the Sun, and I didn’t think much of 1263 because it was near the edge as well. It goes to show you that with our nearest star, it’s best to expect the unexpected!
… and the astronomers with whom I talked were keeping their eyes on several other spots on the Sun as well. The new solar cycle is ramping up, so one thing I can say with some certainty is that we’ll see more and more powerful flares as time goes on.
Sun Unleashes Largest Solar Flare in Years
Space.com | Clara Moskowitz | 2011 Aug 09
An extremely powerful solar flare, the largest in over four years, rocked the sun early Tuesday (Aug. 9), but is unlikely to wreak any serious havoc here on Earth, scientists say.
"It was a big flare," said Joe Kunches, a space scientist with the National Oceanic and Atmospheric Administration (NOAA)'s Space Weather Prediction Center. "We lucked out because the site of the eruption at the sun was not facing the Earth, so we will probably feel no ill effects."
Today's solar flare began at 3:48 a.m. EDT (0748 GMT), and was rated a class X6.9 on the three-class scale scientists use to measure the strength of solar flares. The strongest type of solar eruption is class X, while class C represents the weakest and class M flares are medium-strength events. [Video: A User's Guide to Solar Flares]
The flare is the largest one yet in the sun's current cycle, which began in 2008 and is expected to last until around 2020. Solar activity waxes and wanes over an 11-year sun weather cycle, with the star currently heading toward a solar maximum in 2013.
"This flare had a GOES X-ray magnitude of X6.9, meaning it was more than 3 times larger than the previous largest flare of this solar cycle - the X2.2 that occurred on Feb 15, 2011," scientists with NASA's Solar Dynamics Observatory, a space observatory that monitors the sun, wrote in an update.
Before the Feb. 15 storm, the largest recent solar flare occurred in December 2006, when an X9-class solar storm erupted from the sun. [Video: Aug. 9 Solar Flare Briefly Knocks Out HF Radio]
Solar flares occur when magnetic field lines on the sun get tangled up into knots, building potential energy until they reach a tipping point. Then, that energy is converted into heat, light and the motion of charged particles.
While all X-class solar eruptions are major events, they pose the greatest threat to Earth when they are aimed directly at the planet. During those events the sun often releases a cloud of plasma called a coronal mass ejection into space, and sometimes toward Earth. This ejection hurls charged particles that can damage satellites, endanger astronauts in orbit, and interfere with power systems, communications and other infrastructure on the planet.
Today's solar flare, and resulting coronal mass ejection (CME) was not aimed at us, however. [Anatomy of Sun Storms & Solar Flares (Infographic)]
"Because of its position the CME is going to shoot out into space and not be Earth-directed, and we don’t expect any big geomagnetic storm with this," Kunches told SPACE.com. "We did luck out. If this would have happened a week ago, who knows?"
However, some VLF and HF radio communications blackouts have been reported, according to Spaceweather.com, a website that monitors space weather events.
Whatever particles do head our way should reach us in a few days.
"The cloud will probably miss Earth," SpaceWeather.com wrote. "At this time, however, we cannot rule out a glancing blow from the flank of the CME on or about August 11th."
The plus side of such a collision is often unusually spectacular auroras, or Northern and Southern Lights, which occur when charged particles interact with Earth's magnetic field.
Image Album: Stunning Photos of Solar Flares & Sun Storms
Countdown: The Sun's Wrath: Worst Solar Storms in History
Solar Unrest Culminates in Violent Eruption
Discovery News | Big Pic | Ian O'Neill | 2011 Aug 09
As London erupts with violence, Middle East unrest continues and the world's volatile stock markets careen out of control, the tumultuous sun keeps reminding us that no matter how chaotic things get on Earth, the massive ball of magnetized plasma will always dwarf terrestrial matters.
Early this morning, a powerful X-class flare rocked the solar surface, creating a dazzling show for the orbiting NASA Solar Dynamics Observatory (SDO). As can be seen by the high-definition SDO photograph above, the flare erupted near the solar limb, directed (mostly) away from Earth.
The "X7" flare erupted at the site of the particularly active sunspot 1263 at 3:48 a.m. ET. X-class flares are the strongest classification of solar flares, with C- and M-class flares representing the weakest and medium-strength flares, respectively. The Earth's atmosphere has been buffeted by a series of M-class flares in sunspots 1263 and 1261 over the past few days, prompting the National Oceanic and Atmospheric Administration (NOAA) to issue warnings to satellite operators and power companies around the globe.
Although this morning's flare generated a coronal mass ejection (CME), it is not thought that there will be any major impact to Earth. However, according to SpaceWeather.com's Tony Phillips, there is a minor proton storm in progress -- i.e. high-energy protons buzzing around the vicinity of the Earth's magnetosphere -- that have the potential to cause some satellite damage. There are also reports that the X-ray radiation caused waves of ionization in the Earth's ionosphere, blocking the global transmission of VLF and HF radio frequencies.
BIG PIC: Seeing the Sun in a New Light : First SDO Photographs
RELATED: Zombiesat Attack! Solar Storm Fries Satellite's Brain
How Does the Sun Spark X-Class Solar Flares?
Life's Little Mysteries | Natalie Wolchover | 2011 Aug 09
http://asterisk.apod.com/viewtopic.php?f=8&t=24812
