Zonnevlammen #2: Recht op aarde af

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BIG SUNSPOT: A large sunspot group is rotating over the sun's northeastern limb, possibly signaling an uptick in solar activity. NASA's Solar Dynamics Observatory took this picture during the early hours of Nov. 2nd:

Measuring some 40,000 km wide and at least twice that in length, the behemoth active region is an easy target for backyard solar telescopes. Astronomers are encouraged to monitor the region: NOAA forecasters estimate a 60% chance of M-class solar flares during the next 24 hours. Eruptions today would not be Earth directed, but future eruptions could be as the sunspot turns toward our planet in the days ahead.

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One of the largest sunspots in years is rotating over the sun's northeastern limb. NASA's Solar Dynamics Observatory took this picture of AR1339 during the early hours of Nov. 3rd:

Measuring some 40,000 km wide and at least twice that in length, the sprawling sunspot group is an easy target for backyard solar telescopes. Two or three of the sunspot's dark cores are wider than Earth itself.

Naturally, such a large sunspot has potential for strong flares. NOAA forecasters estimate a 50% chance of M-class solar flares during the next 24 hours. One such eruption has already occured: An M4-flare at 2200 UT on Nov. 2nd produced a bright flash of extreme UV radiation (SDO movie) and hurled a coronal mass ejection (CME) into space. The CME is not heading our way. Future CMEs could have greater effect as AR1339 turns toward Earth in the days ahead

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5 M-class solar flares in 24 hours
November 6, 2011 – Sunspot AR1339 is crackling with M-class solar flares, unleashing at least five of them in the past 24 hours. The blasts have been coming with such thick frequency that photographer Randy Shivak of Elyria, Ohio, was able to catch one in action on Nov. 5th: “Looking like iron filings around a bar magnet, sunspot group 1339 showed itself in the throes of a solar flare,” says Shivak. Even bigger eruptions are possible before the weekend is over. AR1339 has a delta-class magnetic field that harbors energy for X-class flares. The sunspot is turning toward Earth, so the odds of a geo-effective flare are increasing. Sunspot 1339 has a delta-class magnetic field that harbors energy for X-class solar flares.

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Comet Lovejoy (C/2011 W3) is diving into the Sun and furiously vaporizing as it approaches the stellar surface. The Solar and Heliospheric Observatory (SOHO) is recording the kamikaze plunge. “This is, without any doubt, the brightest sungrazing comet that SOHO has ever seen,” says comet researcher Karl Battams of the Naval Research Lab in Washington DC. The comet’s nucleus, thought to be twice as wide as a football field, will skim approximately 140,000 km (1.2 solar radii) above the solar surface on Dec. 15/16. At such close range, solar heating will almost certainly destroy the comet’s icy core, creating a cloud of vapor and comet dust that will reflect lots of sunlight. “If Comet Lovejoy gets as bright as magnitude -4 or -5, there is a tiny but non-zero chance that it could become visible in the sky next to the Sun,” says Battams. Indeed, something similar happened to Comet McNaught in January 2007 when it was visible in broad daylight: gallery. Standing in the shadow of a tall building to block the sun allowed the comet to be seen in blue sky nearby. “Comet Lovejoy will be reaching perihelion (closest approach to the sun) right around sunset on Dec. 15th for people in the US East, Central, Mountain, and Pacific time zones,” continues Battams. “Be alert for the comet to the left of the sun at that time.” Caution: Do not look at or near the sun through unfiltered optics; focused sunlight can seriously damage your eyes. Discovered on Dec. 2nd by amateur astronomer Terry Lovejoy of Australia, the comet is an unusually large member of the Kreutz family. Kreutz sungrazers are fragments of a single giant comet (probably the Great Comet of 1106) that broke apart back in the 12th century. SOHO sees one plunging into the Sun every few days, but most are small, no more than 10 meters wide. Comet Lovejoy is at least ten times larger than usual