| Piú viste - The Sun: just a star, like many others... |
ZA-Solar Sail.jpgThe "Solar Sail"55 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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Sun-Equinox 2002.jpgThe Sun during the 2002 Equinox55 visiteCaption NASA originale:"The active Sun near the March Equinox, the beginning of Autumn in the south and Spring in the northern hemisphere. Recorded in a band of extreme ultraviolet light emitted by highly ionized iron atoms, the Sun's upper atmosphere (or solar corona) shines with an array of active regions and plasma loops suspended in magnetic fields. The bright coronal structures and loops seen here have temperatures of about 1.500.000° K".
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Sun & Comet (dtl-mgnf).jpgA comet approaching the Sun (from SOHO) - detail mgnf55 visiteCaption NASA originale:"Based on their similar orbits, as first worked out by 19th century German astronomer Heinrich Kreutz, all "sungrazers" are believed to originate from a single large "parent comet" which broke up during a perihelion passage perhaps 2.000 years ago. Over time, pieces have continued to split off producing a family of smaller comets which seem to travel in the same orbit".
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Mercury and the Sun.jpgA "Superior Conjunction" Of Mercury55 visiteCaption originale NASA dal "NASA - Picture of the Day" dell'8-9-1999: "In astronomical parlance, an interior planet is at "Superior Conjunction" when it is located on the opposite side of the Sun from Earth. Mercury, the solar system's innermost planet, zips past this point in its orbit today. In fact, in this picture (taken on September 1999) from a solar coronagraph on board the the space-based SOHO observatory, shows Mercury positioned very close to the Sun as seen from a near Earth vantage point. The coronagraph uses an internal occulting disk to block the intense solar glare which otherwise hides this sight from ground-based observers. The shadow of the occulting disk is at the center with the Sun's size and position indicated by the white circle. Mercury is the bright dot with a horizontal line (a digital artifact), while faint dots scattered throughout the field are stars. Bright regions of the sun's outer atmosphere are also visible".
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Hungarian Eclypse.jpgMoments of the last Total Eclipse55 visiteCaption NASA originale:"Only in the fleeting darkness of a total solar eclipse is the light of the Solar Corona easily visible from Earth. Normally overwhelmed by the bright solar disk, the expansive corona, the Sun's outer atmosphere, is an alluring sight. But the subtle details and extreme ranges in the corona's brightness discernible to the eye are notoriously difficult to photograph. In this series of images recorded from Siofok, Hungary during the total phase of the August 11, 1999 eclipse, progressively longer exposures (top left to bottom center) have been used to more faithfully capture different regions of the elusive solar corona. The final image (at bottom right) shows light from the solar disk emerging from behind the moon's edge at the end of totality".
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ZZ-The Sun.jpgAutumnal Equinox 199455 visiteDa "NASA - Picture of the Day" del 20 Marzo 2005:"Today, the Sun crosses the celestial equator heading North, marking the Vernal Equinox - such as the 1st day of Spring in the Northern Hemisphere and Autumn in the south. Equinox means equal night and with the Sun on the celestial equator, Earthlings will experience 12 hours of daylight and 12 hours of darkness. For those in the Northern Hemisphere, the days will continue to grow longer with the Sun marching higher in the sky as Summer approaches. A few weeks after the northern Autumnal Equinox of 1994, the Crew of the Shuttle Endeavor recorded this image of the Sun poised above the Earth's limb. Glare illuminates Endeavor's vertical tail (pointing toward the Earth) along with radar equipment in the payload bay. The space shuttle is expected to return to flight later this year with the launch of STS-114".
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ZZ-ZZ-Annular_seip_big.jpgThe "Annular Eclipse" of October, 3rd, 2005 (HR)55 visiteDa "NASA - Picture of the Day" del 5 Ottobre 2005:"On Monday, part of the Sun went missing. The missing piece was no cause for concern because the Moon was only momentarily in the way. The event was not a total eclipse of the Sun for any Earth-bound sky enthusiast but rather, at best, an annular eclipse, where the Moon blocked most of the Sun. Because of the relatively large distance to the Moon during this Earth-Moon-Sun alignment, the Moon did not have a large enough angular size to block the entire Sun. Those who witnessed the solar eclipse from a narrow path through Spain and Africa, however, were lucky enough to see the coveted Ring of Fire, a dark Moon completely surrounded by the brilliant light of the distant Sun. Pictured above is a Ring of Fire captured two days ago in unusually HR above Spain. The resulting image shows details of the granular solar surface as well as many prominences around the Sun".
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The Sun-W00011347.jpgThe Sun from Cassini55 visiteOriginal caption:"W00011347.jpg was taken on October 23, 2005 and received on Earth October 24, 2005. The camera was pointing toward SATURN-E-RING at approximately 6.847.402 kilometers away and the image was taken using the CL1 and IRP0 filters. This image has not been validated or calibrated".
Secondo noi questa è un'immagine del Sole e non un'istantanea relativa all'Anello E di Saturno. Un'immagine ottenuta casualmente: uno scatto nel buio, mentre una delle fotocamere di Cassini "cercava" l'Anello E.
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Solar Eclypse 2006-tse2006_ayiomamitis_f.jpgThe "Diamond Ring"55 visiteDa "NASA - Picture of the Day" del 30 Marzo 2006:"The track of totality for the first solar eclipse of 2006 began early yesterday on the East coast of Brazil and ended half a world away at sunset in Western Mongolia. In between, the shadow of the Moon crossed the Atlantic Ocean, Northern Africa, central Asia and so came for a moment to the small Greek island of Kastelorizo in the Eastern Aegean.
Astronomer Anthony Ayiomamitis reports that the islanders and many eclipse-watching visitors were indeed treated to an inspiring display of the beautiful Solar Corona as totality lasted about 3 minutes.
As the total phase of the eclipse ended, he was able to capture this striking "Diamond Ring" image. In it, the first rays of sunlight shining through edge-on lunar valleys create the fleeting appearance of glistening diamonds set in a bright ring around the Moon's silhouette".
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Solar Eclipse 2006.jpgFrom Space, from Earth...55 visiteDa "NASA - Picture of the Day" del 31 Marzo 2006:"Neither rain, nor snow, nor dark of night can keep the space-based SOlar Heliospheric Observatory (SOHO) from watching the Sun. In fact, from its vantage point 150 MKM sunward of planet Earth, SOHO's cameras can always monitor the Sun's Outer Atmosphere, or Corona.
But only during a total solar eclipse can earth-based observers see the lovely coronal streamers and structures - such as when the Moon briefly blocks the overwhelmingly bright solar surface.
In this composite view, SOHO's uninterrupted view of the Solar Corona above the Solar Photosphere (center) and Corona far beyond the Sun's disk, are shown in orange hues. The middle, donut-shaped region is the Corona as recorded by the Williams College Eclipse Expedition to Kastelorizo Island, Greece during the March 29th, 2006 total solar eclipse.
Merging ground and space-based views allows astronomers to trace features in the Corona that reach from just above the Sun's surface into the Solar Wind".
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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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The Sun-EITquadsA.jpgMulticolor and Multispectrum...55 visitenessun commento
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