| Piú viste - The Sun: just a star, like many others... |
Solar_Prominence~0.jpgSolar Prominence67 visiteCaption NASA, da "NASA - Picture of the Day" del giorno 23 Marzo 2010:"Dramatic Prominences can sometimes be seen looming just beyond the edge of the Sun.
Such was the case last week as a Giant Prominence, visible above on the right, highlighted a Sun showing increased activity as it comes off an unusually quiet Solar Minimum. A changing carpet of hot gas is visible in the Chromosphere of the Sun in the above image taken in a very specific color of light emitted by Hydrogen.
A Solar Prominence is a cloud of Solar Gas held just above the Surface by the Sun's Magnetic Field. The Earth would easily fit below the Prominence on the right. Although very hot, Prominences typically appear dark when viewed against the Sun, since they are slightly cooler than the Surface.
A quiescent Prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. The next day, the same prominence looked slightly different".MareKromium
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Athmosferic_Corona-Schneider.jpgDiamond Ring and Shadow Bands67 visiteDalla Rubrica "NASA - Picture of the Day" del giorno 24 Luglio 2010:"As the total phase of July ,11th, 2010 Solar Eclipse came to an end, Sunlight streaming past the edge of the Moon's silhouette created the fleeting appearance of a glistening Diamond Ring in the sky.
Seen through a thin cloud layer from the French Polynesian atoll of Hao it also produced remarkable Shadow Bands, flickering across the dramatic scene. Projected onto the cloud layer, the Shadow Bands are parallel to the sliver of Sunlight emerging from behind the Moon's edge.
Caused by turbulence in Earth's Atmosphere refracting the sliver of Sunlight, the narrow bands were captured in this brief, 1/400th second exposure. Shining through the cloud droplets, the Sunlight also produced a luminous atmospheric corona, not to be confused with the Solar Corona seen during Eclipse Totality.
The Atmospheric Corona is centered on the bright diamond of emerging Sunlight".MareKromium
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Sunspots - SST.jpgSunspots66 visiteCaption NASA originale:"This stunning image shows remarkable and mysterious details near the dark central region of a planet-sized sunspot in one of the sharpest views ever of the surface of the Sun. Just released, the picture was made using the Swedish Solar Telescope now in its first year of operation on the Canary Island of La Palma. Along with features described as hairs and canals are dark cores visible within the bright filaments that extend into the sunspot, representing previously unknown and unexplored solar phenomena".
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Solar Prominence.jpgSolar "Blow"...66 visiteDa "NASA - Picture of the Day" del 7 Agosto 2006:"Our Sun is still very active. In the year 2000, our Sun went though Solar Maximum, the time in its 11-year cycle where the most sunspots and explosive activities occur. Sunspots, the Solar Cycle, and Solar Prominences are all caused by the Sun's changing magnetic field.
Pictured above is a solar prominence that erupted in 2002, July, throwing electrons and ions out into the Solar System.
The above image was taken in the ultraviolet light emitted by a specific type of Ionized Helium, a common element on the Sun. Particularly hot areas appear in white, while relatively cool areas appear in red. Our Sun should gradually quiet down until Solar Minimum occurs, and the Sun is most quiet. No one can precisely predict when Solar Minimum will occur, although some signs indicate that it has started already".
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The_Sun-PIA09330.jpgThe South Pole of the Sun66 visiteSTEREO, a two-year mission, launched October 2006, will provide a unique and revolutionary view of the Sun-Earth System. The two nearly identical observatories -- one ahead of Earth in its orbit, the other trailing behind -- will trace the flow of energy and matter from the Sun to Earth. They will reveal the 3D structure of coronal mass ejections; violent eruptions of matter from the sun that can disrupt satellites and power grids, and help us understand why they happen. STEREO will become a key addition to the fleet of space weather detection satellites by providing more accurate alerts for the arrival time of Earth-directed solar ejections with its unique side-viewing perspective. MareKromium
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Solar_Corona-TSE2010_JLD4.jpgThe "Crown" of the Sun66 visiteDalla Rubrica "NASA - Picture of the Day" del giorno 21 Luglio 2010:"During a total Solar Eclipse, the Sun's extensive Outer Atmosphere, or Corona, is an inspirational sight. Subtle shades and shimmering features that engage the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single photograph.
But this composite of 7 consecutive digital images over a range of exposure times comes close to revealing the Crown of the Sun in all its glory. The telescopic views were recorded from the Isla de Pascua (Easter Island) during July, 11th, 2010 Total Solar Eclipse and also show solar prominences extending just beyond the edge of the eclipsed Sun.
Remarkably, features on the dim, Near Side of the New Moon can also be made out, illuminated by Sunlight reflected from a Full Earth".MareKromium
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At the edge of the Sun.jpgAt the edge of the Sun65 visiteCaption NASA originale: "Dramatic prominences can sometimes be seen looming just beyond the edge of the Sun. A Solar Prominence is a cloud of solar gas held just above the surface by the Sun's magnetic field. The Earth would easily fit below the prominence on the left. A quiescent prominence typically lasts about a month and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although very hot, prominences typically appear dark when viewed against the Sun, since they are slightly cooler than the surface. The above image - in false color - was taken on June 1st, 2003, from Stuttgart, Germany, with a simple amateur telescope and camera".
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The limb of the Sun.jpgThe limb of the Sun64 visiteFotografia amatoriale della corona solare durante l'ultima grande eclissi totale del 1999.
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ZZ-ZZ-HybridEclypse-Heinsius_Panama_tse2005_1.jpgAn unusual "Hybrid Solar Eclipse" (2)64 visiteDa "NASA - Picture of the Day" del 6 Maggio 2005:"(...) But for Stephan Heinsius, near the end of the shadow track at Penonome Airfield, Panama, the Moon's apparent size had shrunk enough to create an anular eclipse, showing a complete anulus of the Sun's bright disk as a dramatic "Ring of Fire".
(...) How rare is such a Hybrid Eclipse?
Calculations show that during the 21st century just 3,1% (7 out of 224) of Solar Eclipses are hybrid while hybrids comprise about 5% of all Solar Eclipses over the period from 2.000 BC to AD 4.000".
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The_Sun-PIA09322.jpgClose-up View of an Active Region of the Sun (March 23, 2007)63 visitenessun commentoMareKromium
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The Sun from Soho.jpgA "Solar Prominence" from Soho62 visiteCaption NASA originale:"A 'Solar Prominence' is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. The Earth would easily fit under the hovering curtain of hot gas (like the one pictured above). A quiescent prominence typically lasts about one month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although somehow related to the Sun's changing magnetic field, the energy mechanism that creates and sustains a Solar Prominence is still a mistery".
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Sun & Comet (2).jpgA comet approaching the Sun (from SOHO)62 visiteCaption NASA originale:"SOHO, the space-based SOlar and Heliospheric Observatory, has become by far the reigning champion facility for discovering comets, its total having reached more than 200. As might be expected of a solar observatory, most of the SOHO discovered comets are "sungrazers", such as comets destined to dive within a mere 50.000 Km or so of the solar photosphere.
At that range the intense heat and gravitational forces make it unlikely these primitive chunks of ice and dust will survive".
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