The Sun: just a star, like many others...
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The_Sun-Spicules.jpgSpiculae in Solar Region 1109279 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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The_Sun-Texture.jpgThe "Texture" of the Sun54 visiteUp close, the Solar Surface is a striking patch work of "granules" in this very High Resolution picture of the quiet Sun. Caused by convection, the granules are hot, rising columns of plasma edged by dark lanes of cooler, descending plasma. But the HR view reveals that the dark lanes are dotted with many small, contrasting bright points. Constantly present on the Solar Surface, the bright points do not seem to be related to Sunspots that come and go with the Magnetic Solar Cycle.
Nonetheless, the bright points are regions of concentrated Magnetic Fields and are bright because the magnetic pressure opens a window to hotter deeper layers below the Photosphere. For scale, the white bar at the lower left corresponds to approx. 5000 Km across the Sun's Surface.
The sharp, narrow-band image was recorded in September, 2007 using the Swedish Solar Telescope on the astronomical island of La Palma.MareKromium
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The_Sun-XClass_Flare-SDO20110215_015332_2048_0193.jpgSolar "X-Class" Flare85 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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The_Sun.JPGCold Sun? (All Filters; credits: SOHO & Dr M. Faccin)54 visitenessun commentoMareKromium
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The_Sun.jpgNever too close, never too far...53 visiteCaption NASA:"When is the Sun most distant from Earth? It happened again just this past weekend.
A common misconception is that the Sun is most distant during the Winter, when it's the coldest. In truth, however, the seasonal temperatures are more greatly influenced by the number of daylight hours and how high the Sun rises.
For example, during Northern Winter, the tilt of the Earth causes the Sun to be above the horizon for a shorter time and remain lower in the sky than in Northern Summer. The picture compares the relative size of the Sun during Earth's closest approach in January (Northern Winter) on the left, and in July (Northern Summer) on the right. The angular size of the Sun is noticeably smaller during July, when it is farther away. If the Earth's orbit was perfectly circular, the Sun would always appear to be the same size.
These two solar images were taken from Spain during 2006, but the same effect can be seen in any year from any Earth-bound location".MareKromium
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The_Sun_-_Eclipse.jpgAt the Sun's Edge54 visiteCaption NASA:"A train trip on the Trans-Siberian railway to Novosibirsk resulted in this stunning view along the edge of the Sun, recorded during the August 1st, 2008, total Solar Eclipse.
The picture is a composite of two images taken at special moments in the eclipse sequence, corresponding to the very beginning and the very end of the total eclipse phase.
Those times are known to eclipse chasers as 2nd and 3rd contact.
Bright beads around the Moon's dark silhouette are rays of sunlight shining through lunar valleys at the edge of the Lunar Disk.
But the composite view also captures Solar Prominences, such as "looping structures" of hot plasma suspended in magnetic fields, extending beyond the Sun's edge".MareKromium
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The_Sun_and_Mercury.jpgThe Sun and Mercury54 visiteEnjoying the transit of Mercury from Dallas, Texas, astronomer Phil Jones recorded this detailed image of the Sun. Along with a silhouette of the innermost Planet, a network of cells and dark filaments can be seen against a bright solar disk with spicules and prominences along the Sun's edge. The composited image was taken through a telescope equiped with an H-alpha filter that narrowly transmits only the red light from Hydrogen atoms. Such images emphasize the Solar Chromosphere, the region of the Sun's atmosphere immediately above its Photosphere or normally visible surface. Left of center, the tiny disk of Mercury seems to be imitating a small sunspot that looks a little too round. But in H-alpha pictures, sunspot regions are usually dominated by bright splotches (called plages) on the Solar Chromosphere.
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The_Sun_from_SOHO_-_Coronal_Mass_Ejection.jpgCoronal Mass Ejection54 visiteCaption NASA originale:"What's happening to our Sun? Another Coronal Mass Ejection (CME)!
The Sun-orbiting SOHO spacecraft has imaged many erupting filaments lifting off the active solar surface and blasting enormous bubbles of magnetic plasma into space. Direct light from the sun is blocked in the inner part of the above image, taken in 2002, and replaced by a simultaneous image of the Sun in ultraviolet light.
The field of view extends over 2 MKM from the Solar Surface. While hints of these explosive events, called Coronal Mass Ejections or CMEs, were discovered by spacecraft in the early 70s, this dramatic image is part of a detailed record of this CME's development from the presently operating SOHO spacecraft.
Near the minimum of the Solar Activity Cycle CMEs occur about once a week, but near solar maximum rates of two or more per day are typical. Strong CMEs may profoundly influence space weather. Those directed toward our Planet can have serious effects".
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The_Sun_in_3D.jpg3-D Sun56 visiteCaption NASA:"What does the Sun look like in all three spatial dimensions? To find out, NASA launched two STEREO satellites to perceive three dimensions on the Sun much like two eyes allow humans to perceive three dimensions on the Earth.
Such a perspective is designed to allow new insight into the surface of the rapidly changing Sun, allowing humans to better understand and predict things like Coronal Mass Ejections and solar flares that affect the Earth as well as satellites and astronauts orbiting the Earth. Pictured above are two simultaneous images of the Sun taken by STEREO A and STEREO B, now digitally combined to give one of the first 3-D pictures of the Sun ever taken. To fully appreciate the image, one should view it with 3-D red-blue glasses. The teeming and bubbling solar surface can be seen sporting a prominent solar prominence near the top of the image".MareKromium
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The_Sun_in_Extreme_UV.jpgThe Sun in Extreme UV54 visiteThis wild-looking portrait of the Sun was made on March 30th, 2010, by the recently launched Solar Dynamics Observatory (SDO).
Shown in false-color, the composite view covers Extreme UltraViolet wavelengths and traces hot plasma at temperatures approaching 1 million Kelvins. At full resolution, SDO image data is intended to explore solar activity in unprecedented detail. In fact, SDO will send 1.5 terabytes of data back each day, equivalent to a daily download of about half a million MP3 songs.MareKromium
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UV Sun.jpgUltraviolet Sun55 visiteDa "NASA - Picture of the Day" del 10 Luglio 2006:"Is this our Sun?
Yes. Even on a normal day, our Sun is sizzling ball of seething hot gas. Unpredictably, regions of strong and tangled magnetic fields arise, causing sunspots and bright active regions. The Sun's surface bubbles as hot Hydrogen gas streams along looping magnetic fields. These active regions channel gas along magnetic loops, usually falling back but sometimes escaping into the Solar Corona or out into space as the solar wind. Pictured above is our Sun in three colors of ultraviolet light. Since only active regions emit significant amounts of energetic ultraviolet light, most of the Sun appears dark. The colorful portions glow spectacularly, pinpointing the Sun's hottest and most violent regions. Although the Sun is constantly changing, the rate of visible light it emits has been relatively stable over the past 5 BY, allowing life to emerge on Earth".
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ZA-Solar Sail.jpgThe "Solar Sail"54 visiteNelle more del lancio del vettore Cosmos 1 (realizzato dalla Planetary Society in collaborazione con lo Space Research Institute -IKI- di Mosca), il quale dovrebbe portare nello spazio la prima sonda capace di usare il Vento Solare quale strumento di propulsione, noi ci domandiamo se questa trovata sia davvero un colpo di genio, oppure una delle "bufale" che, ogni tanto, la NASA o qualche altra Agenzia Spaziale si inventa per giustificare la spendita di fondi e gettare fumo negli occhi del pubblico...
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