MAGNIFICENT MAGNETISM: NASA spacecraft and amateur astronomers alike are monitoring a staggeringly-long filament of magnetism on the sun. It stretches more than a million kilometers around the sun's southeastern limb:
Image credit: Solar and Heliospheric Observatory (SOHO)
As this movie shows, the filament has remained mostly stable for at least two days. However, similar filaments in the past have been known to collapse, and when they hit the surface of the sun--bang! A tremendous explosion called a "Hyder flare" results, sometimes rivaling the strongest flares produced by sunspots. Solar physicists have not yet learned to predict Hyder flares, so we cannot estimate the odds of one now. Readers with solar telescopes are encouraged to monitor developments.
more images: from C. Swiger and J. Stetson of South Portland, Maine; from Mark Townley of Brierley Hill, West Mids, UK; from Cai-Uso Wohler of Bispingen, Germany; from Alan Friedman of downtown Buffalo, NY; from Michael Wilk of Augsburg, Germany [link to www.spaceweather.com]
1. What is a Hyder flare?
Flares are intense brightenings that occur in the solar chromosphere. Flares are generally observed from Earth using narrow band filters, typically with a bandwidth of less than 0.1 nm, and often centred on the Hydrogen-Alpha wavelength of 656.3 nm. (Flares also have counterparts, that is, sudden outbursts, in the radio and X-ray spectrum).
Most flares occur around active regions associated with sunspot groups. However, occasionally a flare (sudden brightening) is observed well away from an active region or sunspot group. These flares are invariably associated with the sudden disappearance of a large (thick, long, 'bushy') dark solar filament, and are termed Hyder flares.
More info on Here Comes the Sun - Thread: HERE COMES THE SUN (Page 6)
And -- Thread: HYDER FLARE ALERT (biggun)