An unusually complex magnetic eruption on the sun has flung a large cloud of electrically charged particles towards Earth. When the cloud hits, which could be anytime now, it could spark aurorae in the skies around the poles and pose a threat to satellites – though probably not a particularly severe one.

On 1 August, a small solar flare erupted above sunspot 1092. It would not have raised many eyebrows, except that a large filament of cool gas stretching across the sun's northern hemisphere also chose that moment to explode into space.

Despite being separated by hundreds of thousands of kilometres, the two events may be linked. Images from NASA's Solar Dynamics Observatory hint at a shock wave travelling from the flare into the filament. "These are two distinct phenomena but they are obviously related," says Len Culhane, a solar physicist at the Mullard Space Science Laboratory, University College London.

Satellite threat

Filaments are gigantic tubes of magnetism that fill up with solar gas and hang in the atmosphere of the sun. This particular one spanned 50 times the diameter of our planet before it burst. It then spilled its contents into space, producing a cloud of electrically charged particles known as a coronal mass ejection.

When the cloud hits our planet, as will happen any day now, satellites could be affected. A gust of solar particles in April may have been responsible for putting Intelsat's Galaxy 15 permanently out of action.

In the grand scheme of solar things, this is not a big eruption. The sun is currently rousing from an unusually extended period of quiet. "If the solar activity continues to rise, then in three to four years this will be seen as a comparatively normal event," says Culhane.

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The original article has a video and an imbedded link to another article by Stuart Clark about the sun's behavior. You may want to skip it if you don't want to know your odds of becoming a charred cinder within 5 years.

Astroboffins are warning that a mighty "eruption" of superhot plasma has been blasted out of the Sun directly at the Earth. The plasma cloud is expected to reach Earth beginning tomorrow, possibly causing strange phenomena - including a mighty geomagnetic storm which could see the Northern Lights aurorae extend as far south as Blighty or the northern USA.

Duck's eye view of the plasma shotgun blast

According to boffins analysing results delivered from NASA's Solar Dynamics Observatory satellite, Sunday saw a massive convulsion involving almost the entire face of the Sun facing Earth. The event was apparently centred on Sunspot 1092, a huge solar pimple so large as to be visible without the aid of a telescope.

It appears that the sunspot may have triggered a huge "coronal mass ejection" in which huge amounts of superhot plasma were spurted towards Earth accompanied by solar flares, tsunamis, magnetic filaments and other sun-wracking upsets across half the sun's surface.

"This eruption is directed right at us, and is expected to get here early in the day on August 4th," says astronomer Leon Golub of the Harvard-Smithsonian Center for Astrophysics (CfA). "It's the first major Earth-directed eruption in quite some time."

Normally a blast of radiation like this could be expected to wipe out much of the human race, but fortunately we are protected by the Earth's magnetic field. Instead the deadly solar plasma is expected to stream down the planetary field lines towards the poles, crashing into oxygen and nitrogen atoms in the atmosphere and so lighting them up to form aurorae - the so-called Northern Lights.

Golub and his colleagues believe that the aurorae may be so intense as to be visible from the northern United States and other countries such as the UK which are normally too far south to see the Lights.

"We got a beautiful view of this eruption," enthuses the astronomer. "And there might be more beautiful views to come, if it triggers aurorae."

The Sun's activity generally rises and falls on an 11-year cycle: the last peak occurred in 2001, but since then the star has been going through an unusually prolonged calm spell. We've been overdue for some more action for several years, and Golub and his colleagues consider that Sunday's outburst may be a sign that the Sun is "waking up".

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A near thing, what? Good job we've got that magnetic field.

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The timing stinks too. I'll be anesthetized for an outpatient medical procedure early tomorrow. I'd hate to wake up and find out I've been incinerated.