| Piú viste - The Sun: just a star, like many others... |
A-The_Sun-SOHO-LASCO-1.gifA Day of the Sun (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)89 visitenessun commentoMareKromium
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The Sun in Hydrogen-Alpha light.jpgThe Sun in "Hydrogen-alpha" light86 visiteCaption NASA originale:"The above picture was taken in a specific color of light emitted by Hydrogen gas called Hydrogen-alpha. Granules cover the solar photosphere surface like shag carpet, interrupted by bright regions containing dark sunspots. Our Sun glows because it is hot, but it is NOT on fire. Fire is the rapid acquisition of oxygen, and there is VERY LITTLE O2 on the Sun! The energy source of the Sun is the nuclear fusion of Hydrogen into Helium (4H--->1He) deep within its core".
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The Sun_s Corona.jpgThe "Corona"86 visiteIn sede di commento a questa immagine (amatoriale, ma non per questo meno bella) della corona solare - come visibile durante un'eclissi totale - una piccola curiosità: sapevate che alcune delle sfumature della corona sono visibili (anzi: percepibili) soltanto dall'occhio umano?
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The_Sun-XClass_Flare-SDO20110215_015332_2048_0193.jpgSolar "X-Class" Flare86 visiteCaption NASA:"On February 14, 2011, the Sun unleashed one of its most powerful explosions, an "X-Class Flare". The blast was the largest so far in the new Solar Cycle. Erupting from Active Region AR1158 in the Sun's Southern Hemisphere, the Flare is captured here in this extreme UltraViolet image from the Solar Dynamics Observatory (SDO). The intense burst of electromagnetic radiation momentarily overwhelmed pixels in SDO's detectors causing the bright vertical blemish.
This "X-Class Flare" was also accompanied by a Coronal Mass Ejection (CME), a massive cloud of charged particles traveling outward at nearly 900 Km per second".MareKromium
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Sun_Spot.jpgA really beautiful and DEEP SunSpot85 visitenessun commentoMareKromium
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ZA-Sunspot.jpgSunspot and Solar "granules" (detail mgnf)83 visiteCaption NASA originale:"Sometimes, small regions of the Sun appear unusually dark. Visible above is a close-up picture of a sunspot, a depression on the Sun's face that is slightly cooler and less luminous than the rest of the Sun. Sunspots can be larger than the Earth and usually last for only a few days. As you can see, the Sun's face is a bubbling sea of separate cells of hot gas. These cells are known as "granules" and a solar "granule" is about 1000 Km across and "lives" for + or - 10 minutes, then explodes".
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Sunrise from Space.jpgSunrise from space...82 visiteCaption NASA originale:"Sunrise seen from low Earth orbit by the shuttle astronauts can be very dramatic indeed. In this view, the Sun is just visible peaking over towering anvil-shaped storm clouds whose silhouetted tops mark the upper boundary of the troposphere, the lowest layer of planet Earth's atmosphere. Sunlight filtering through suspended dust causes this dense layer of air to appear red. In contrast, the blue stripe marks the stratosphere, the tenuous upper atmosphere, which preferentially scatters blue light".
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Sun-PIA03149_modest.jpgSolar Flares from Soho81 visiteCaption NASA originale:"Extreme Ultraviolet Imaging Telescope (EIT) image of a huge, handle-shaped prominence taken on Sept. 14,1999 taken in the 304 angstrom wavelength - Prominences are huge clouds of relatively cool dense plasma suspended in the Sun's hot, thin corona. At times, they can erupt, escaping the Sun's atmosphere. Emission in this spectral line shows the upper chromosphere at a temperature of about 60,000 degrees K. Every feature in the image traces magnetic field structure. The hottest areas appear almost white, while the darker red areas indicate cooler temperatures".
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The_Sun-Spicules.jpgSpiculae in Solar Region 1109281 visiteCaption NASA:"Imagine a pipe as wide as a state and as long as the Earth. Now imagine that this pipe is filled with hot gas moving 50.000 Km per hour. Further imagine that this pipe is not made of metal but a transparent Magnetic Field. You are envisioning just one of thousands of young Spicules (Spiculae) on the active Sun.
Pictured above is one of the highest resolution image yet of these enigmatic Solar Flux Tubes. Spicules line the above frame of SAR 11092 that crossed the Sun last month, but are particularly evident converging on the Sunspot on the lower right.
Time-sequenced images have recently shown that Spicules last about five minutes, starting out as tall tubes of rapidly rising gas but eventually fading as the gas peaks and falls back down to the Sun. What determines the creation and dynamics of Spicules still remains a topic of the active Solar Research".MareKromium
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Sun-prom1743_eit_big.jpgAnother "Solar Prominence" from Soho80 visiteCaption NASA originale:"This large prominence is significant not only for its size, but also for its shape. The picture was taken early in the year 2000 by the Sun-orbiting SOHO satellite. Although large prominences and energetic Coronal Mass Ejections (CMEs) are relatively rare, they are occurred more frequently near Solar Maximum, such as the time of peak sunspot and solar activity in the 11 year solar cycle".
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Black Sun.jpgBlack Sun80 visiteCaption NASA originale:"During a total solar eclipse, Earth's moon blocks the Sun - almost exactly. While the Sun is about 400 times wider than the Moon, it is also about 400 times farther away and each appears to be half a degree or so in diameter. On August 11, 1999 this remarkable coincidence in the apparent size of two vastly different celestial bodies produced tantalizing solar spectacles for denizens of Europe and Asia. For example, prominences along the Sun's limb peer around the Moon's dark edge in this dramatic picture of totality recorded as the lunar shadow swept across Hungary. Subtle structures in the Sun's inner corona are also visible streaming beyond the silhouetted Moon".
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The_Sun-489332main_euvfilament-20101016-1.jpgIntense Solar Activity on the Sun: Sunspot 1112 and Solar Flares76 visiteOn Saturday, October 16, 2010, NASA’s Solar Dynamics Observatory captured this stunning image of one of the most intense, Solar Flares seen in the past few months. So far there have been no reports of energetic particles from this M-class Flare interfering with NASA Spacecraft or making their way to Earth.MareKromium
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