Wired: Huge Magnetic Filament Erupts on the Sun

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Wired: Huge Magnetic Filament Erupts on the Sun

Post by bystander » Mon Dec 06, 2010 7:16 pm

Huge Magnetic Filament Erupts on the Sun
Wired Science | Lisa Grossman | 06 Dec 2010
A magnetic filament more than 50 times the Earth’s width is erupting off the surface of the sun.

The loop of hot plasma has been snaking around the sun’s southeast limb since Dec. 4, and appears to be growing by the hour. When NASA’s Solar Dynamics Observatory saw it on Dec. 4, the filament was more than 250,000 miles long, about 30 times the diameter of the Earth. In this new image, taken at 9:30 am PST on Dec. 6, the loop of charged plasma stretches more than 435,000 miles, the full radius of the sun itself.

So far the gigantic prominence has hung suspended peacefully above the sun’s surface, but this morning it started showing signs of instability. Long filaments like this one can break apart as coronal mass ejections, releasing tons of hot, charged material into the inner solar system and causing magnetic storms on Earth. If the filament collapses in the next day or so, the results could be spectacular.

This prominence is an excellent target for backyard telescopes. If you capture any great sun photos in the next few days, let us know.

Image: NASA/GSFC/SDO
Breaking News: Watch A Gigantic Looping Solar Prominence
Universe Today | Nicholos Wethington | 06 Dec 2010
Click to play embedded YouTube video.
A HUGE looping prominence on the Sun!
Discover Blogs | Bad Astronomy | 06 Dec 2010
  1. First, there is very little danger to Earth from this event. Prominences like this tend to be local to the Sun, and collapse after a few hours. As far as I can tell, there are no flares or coronal mass ejections associated with this, which are what can hurt satellites and power grids here at home. So rest easy, and enjoy the beauty of this thing.
  2. Amazingly, there is no hint of this event in this SDO visible light image (seen here; click to embiggen) taken at nearly the same time. The false-color image of the prominence above is actually taken in the ultraviolet, where low-density helium glows. In visible light, the light from the extremely thin material in the prominence is totally overwhelmed by the intense emission from the Sun’s surface, and is invisible. It’s only when we filter out most of the Sun’s light (and let through light specifically given off by the plasma in the prominence) that we can see it at all.
  3. Note that the dark sunspots in the visible light image are seen as being very bright in the ultraviolet helium image. The Sun’s magnetic field is incredibly complex, with gigantic loops of magnetic field lines piercing through the Sun’s surface and re-entering some distance away. Sunspots are where the magnetic field strength is high. This prevents the gas from rising and falling in the Sun, so packets of gas boiling up from below reach the surface and cool off a bit, darkening. But in the ultraviolet, the magnetic energy is more easily seen, making the spots look bright.
That goes to show you that what we see in the heavens is not all we get. Our understanding of the Sun comes from centuries of observations, but it’s only been in the past few decades that we’ve let our vision widen to include light our eyes cannot detect. And when we do that we find our local star to be a vastly more interesting place than we had ever dreamed of.
SpaceWeather.com - 06 Dec 2010
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Re: Wired: Huge Magnetic Filament Erupts on the Sun

Post by neufer » Mon Dec 06, 2010 7:55 pm

Image
bystander wrote:Huge Magnetic Filament Erupts on the Sun
Wired Science | Lisa Grossman | 06 Dec 2010
A magnetic filament more than 50 times the Earth’s width is erupting off the surface of the sun. The loop of hot plasma has been snaking around the sun’s southeast limb since Dec. 4, and appears to be growing by the hour. When NASA’s Solar Dynamics Observatory saw it on Dec. 4, the filament was more than 250,000 miles long, about 30 times the diameter of the Earth. In this new image, taken at 9:30 am PST on Dec. 6, the loop of charged plasma stretches more than 435,000 miles, the full radius of the sun itself.
Art Neuendorffer

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Re: Wired: Huge Magnetic Filament Erupts on the Sun

Post by Beyond » Mon Dec 06, 2010 11:55 pm

Neufer, i think you may have to change the caption on the left hand picture from ...Erupts on the sun--to...Erupts on the Daughter. :)
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CfA: Sneak Attacks from the Sun

Post by bystander » Wed Dec 08, 2010 12:42 am

Sneak Attacks from the Sun
Center for Astrophysics | 07 Dec 2010
Our Sun can be a menace when it sends out powerful solar blasts of radiation towards the Earth. Astronomers keenly watch the Sun to learn more about what powers these solar eruptions, in hopes of being able to predict them. New research shows that one-third of the Sun's blasts are "sneak attacks" that may occur without warning.

"If space weather forecasters rely on some of the traditional danger signs, they'll miss a significant fraction of solar eruptions," said Suli Ma of the Harvard-Smithsonian Center for Astrophysics (CfA).

To reach their conclusion, Ma and her colleagues studied 34 solar eruptions over 8 months using the STEREO spacecraft. STEREO allows us to study the Sun from two different angles simultaneously. It consists of two spacecraft, one ahead of Earth in its orbit and the other trailing behind. The researchers used it to ensure that the events leaving the Sun were definitely on the side facing the Earth.

STEREO is ideal for studying coronal mass ejections, or CMEs. A CME is a huge eruption from the Sun that blasts a billion tons of highly charged particles into space at speeds greater than a million miles per hour. When those charged particles reach Earth, they interact with our planet's magnetic field, potentially creating a geomagnetic storm. Such a storm can interfere with satellite communications, disrupt power grids, or even short out orbiting satellites.

Previous to STEREO, astronomers thought that all Earth-facing CMEs were accompanied by warning signals like flares (smaller explosions accompanied by high-energy radiation), coronal dimmings (darkening of the corona caused by discharge of matter in the CME) or filament eruptions (long ribbons of plasma arching violently out from the solar surface). Therefore, by watching for those signals, we could potentially predict an impending eruption.

This new research found that 11 of the 34 CMEs observed by STEREO were "stealthy," showing none of the usual signals. As a result, any system designed to watch for such warning signs could miss one-third of all solar blasts.

"Meteorologists can give days of warning for a hurricane, but only minutes for a tornado," explained Smithsonian astronomer Leon Golub. "Currently, space weather forecasting is more like tornado warnings. We might know an eruption is imminent, but we can't say exactly when it will happen. And sometimes, they catch us by surprise."

The team plans to continue looking for subtle clues that might allow us to predict an impending "stealth" CME. They caution that their study occurred during a prolonged minimum of solar activity; conditions may change as solar activity increases over the next few years.

"The Sun is entering its stormy season, ramping up toward its next period of maximum activity in 2013 and 2014," said Ma. "The more we learn and understand about it now, the better."

The paper discussing their findings appeared in the Oct. 10, 2010 issue of The Astrophysical Journal. It was authored by Suli Ma, G. Attrill, and Leon Golub (CfA); and J. Lin (Chinese Academy of Sciences).
Statistical Study of Coronal Mass Ejections With and Without Distinct Low Coronal Signatures - S Ma et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor