| Piú viste - The Sun: just a star, like many others... |
Sunflare.jpgA Sunflare from the Skylab73 visiteUn'immagine d'epoca: l'anno è il 1973 e dallo Skylab (allora conosciuto come "Il Laboratorio Spaziale") ci arriva l'immagine di una "fiaccola" o, se preferite, di un "Solar Flare".
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The_Sun-489332main_euvfilament-20101016-2.jpgIntense Solar Activity on the Sun: Sunspot 1112 and Solar Flares73 visiteOctober 16, 2010 - Fast-growing sunspot 1112 is crackling with solar flares. The three strongest of this 24 hour period: an M3-flare at 1910 UT on Oct. 16th, a C1-flare at 0900 UT and another C1-flare at 1740 UT on Oct. 17th. So far, none of the blasts has hurled a substantial CME (Coronal Mass Ejection) toward Earth.
In addition, a vast Filament of Magnetism is cutting across the Sun's Southern Hemisphere, measuring about 400.000 Km. A bright 'hot spot' just North of the Filament's midpoint is UV radiation from Sunspot 1112.
The proximity is no coincidence; the filament appears to be rooted in the Sunspot below. If the Sunspot flares, it could cause the entire structure to erupt. But so far, none of the Flares has destabilized the Filament.MareKromium
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Sunspot.jpgSunspots' Region 87572 visiteCaption NASA originale (da "NASA - Picture of the Day" del 2 Maggio 2006):"An unusually active Sunspot Region is now crossing the Sun.
The Region, numbered 875, is larger than the Earth and has produced several Solar Flares over the past week. It should take a few more days for Sunspot 875 to finish crossing the solar disk. The above image of the Sun was taken last Wednesday in a very specific color of red light to bring up detail. Sunspot 875, in the midst of erupting a large "Class C" Solar Flare, can be seen as the dark region to the upper right. In the above image, relatively cool regions appear dark while hot regions appear bright.
On the far left, solar prominences are visible hovering above the Sun's surface".
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The_Sun-489332main_euvfilament-20101016-4.jpgIntense Solar Activity on the Sun: Sunspot 1112 and Solar Flares72 visitePartial Filament Eruption.MareKromium
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The_Sun-489332main_euvfilament-20101016-3.jpgIntense Solar Activity on the Sun: Sunspot 1112 and Solar Flares72 visiteImage of Sunspot Region 1112 (dated October, 18. 2010) as it continues to rotate towards the South Eastern Rim of the Sun.MareKromium
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The_Sun-489332main_euvfilament-20101016-0.jpgIntense Solar Activity on the Sun: Sunspot 1112 and Solar Flares71 visitenessun commentoMareKromium
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Coronal Mass Ejection.jpgA "Coronal Mass Ejection"70 visiteCaption NASA originale:"Magnetic fields buckle releasing previously constrained hot material from the upper atmosphere of the Sun. As a result, hot gas streams out into the Solar System, impacting planets, moons, spacecraft, and making space a dangerous place for astronauts. Known as "Coronal Mass Ejections" (CMEs), billions of tons of scathing plasma can be accelerated to millions of miles per hour. CMEs are more common but less intense than solar flares".
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ZZ-PIA00450.jpgThe Sun from 4 Billion Miles - Voyager 269 visiteCaption NASA originale:"This image of the Sun was taken by the Voyager 1 on Feb. 14, 1990, when it was approximately 32° above the plane of the ecliptic and at a slant-range distance of approximately 4BM. It is the first - and may be the only - time that we will ever see our Solar System from such a vantage point. This image is a portion of a wide-angle image containing the Sun and the region of space where the Earth and Venus were at the time. The wide-angle was taken with the camera's darkest filter (a methane absorption band) and the shortest possible exposure (5/1000 sec.) to avoid saturating the camera's vidicon tube with scattered sunlight. The Sun is not large in the sky as seen from Voyager's perspective at the edge of the Solar System but is still 8M times brighter than the brightest star in Earth's sky: Sirius.
The result of the brightness is a bright burned out image with multiple reflections from the optics in the camera. The "rays" around the Sun are just a diffraction effect".
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Coronal Loops-TRACE.jpgCoronal loops69 visiteDa "NASA - Picture of the Day" del 14 Agosto 2005:"Why is the Corona of the Sun so hot? Extending above the photosphere or visible surface of the Sun, the faint, tenuous Solar Corona can't be easily seen from Earth, but it is measured to be hundreds of times hotter than the photosphere itself. Astronomers have long sought the source of the Corona's heat in magnetic fields which loft monstrous loops of solar plasma above the photosphere. Detailed observations of coronal loops from the orbiting TRACE satellite are pointing more closely to the unidentified energy source. Recorded in extreme ultraviolet light, this and other TRACE images indicate that significant heating occurs low in the corona, near the bases of the loops as they emerge from and return to the solar surface. This tantalizing TRACE image shows clusters of the majestic, hot coronal loops which span 30 or more times the diameter of planet Earth".
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A - The Sun.jpgThe Sun (and a "Sun-Grazer") from Soho68 visiteSun Data and Statistics
Mass (kg) = 1.989e+30
Mass (Earth = 1) = 332,830
Equatorial radius = 695.000 Km
Equatorial radius (Earth = 1) = 108,97
Mean density (gm/cm^3) = 1,410
Rotational period (days) = from 25 up to 36
Escape velocity = 618,02 Km per second
Luminosity (ergs/sec) = 3.827e33
Magnitude (Vo) = - 26,8
Mean surface temperature = 6.000°C
Age (billion years) = approx. 4.5
Principal chemistry: Hydrogen 92,1%; Helium 7,8%; Oxygen 0,061%; Carbon 0,030%; Nitrogen 0,0084%; Neon 0,0076%; Iron 0,0037%; Silicon 0,0031%; Magnesium 0,0024%; Sulfur 0,0015%; others 0,0015%
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Sun-TRACE.jpgThe Sun from TRACE in ultra-violet light67 visiteCaption NASA originale:"Shown in ultraviolet light, the relatively cool dark regions have temperatures of thousands of degrees Celsius. Large sunspot group AR 9169 is visible as the bright area near the horizon. The bright glowing gas flowing around the sunspots has a temperature of over 1.000.000° C. The reason for the high temperatures is still unknown but thought to be related to the rapidly changing magnetic field loops that "channel" solar plasma.
Sunspot group AR 9169 moved across the Sun during September 2000 and decayed in a few weeks".
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Coronal Aurora - ISS.jpgCoronal Aurora from Space67 visiteOriginal caption:"From the ground, spectacular auroras seem to dance high above. But the International Space Station (ISS) orbits at nearly the same height as many auroras, sometimes passing over them, and sometimes right through them. Still, the auroral electron and proton streams pose no direct danger to the ISS. In 2003, ISS Science Officer Don Pettit captured the green aurora, pictured above in a digitally sharpened image. From orbit, Pettit reported that changing auroras appeared to crawl around like giant green amoebas. Over 300 Km below, the Manicouagan Impact Crater can be seen in northern Canada, planet Earth".
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