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Tópico em 'Astronomia' iniciado por luismeteo3 2 Abr 2017 às 21:16.
SOLAR WIND SPARKS AURORAS: For the 4th day in a row, Earth is inside a stream of solar wind flowing from a wide hole in the sun's atmosphere. Last night the action of this gaseous material from our star sparked a veritable explosion of auroras over Narvik, Norway.
Photographer Oliver Wright witnessed the display and says "it was the brightest and fastest corona I have seen in my four years as an aurora tour guide." http://spaceweather.com/images2017/10nov17/narvik1_strip.jpg
A "corona" is a form of aurora borealis that seems to rain down on observers from directly overheard. It is widely regarded as the holy grail of aurora watching--a kind of "bucket list" display. The corona over Narvik was moving so fast, it was a bit blurred in Wright's photo even with a lightning-fast 0.25 second exposure.
Around the Arctic Circle, more auroras are in the offing. The solar wind continues to blow faster than 600 km/s, and NOAA forecasters say there is a 50% chance of G1-class geomagnetic storms on Nov. 10th.
UNUSUAL MAGNETIC FILAMENT: NASA's Solar Dynamics Observatory is monitoring an unusual filament of magnetism on the sun. This image, taken on Nov. 22nd, shows where magnetic forces are holding a massive curl of dense plasma just above the stellar surface:
Magnetic filaments on the sun are not uncommon. Usually they are linear, stretching in only one direction. This one, however, curls back on itself, circumscribing a region more than 280,000 km in diameter. The unusual architecture of the region may undermine its stability. Magnetic fields that criss-cross, like mismatching ends of an incomplete circle, can explode--a process called "magnetic reconnection." Any eruptions this week would likely be Earth-directed.
The scale of this filament makes it an easy target for backyard solar telescopes. Monitoring is encouraged.