| Piú votate - Asteroids and Comets |
Comets-Comet_SWAN-3.jpgComet "SWAN"56 visiteDa "NASA - Picture of the Day" del 4 Ottobre 2006:"A newly discovered comet has brightened enough to be visible this week with binoculars. The picturesque comet is already becoming a favored target for northern sky imagers. Pictured above just last week, Comet SWAN showed a bright blue-green coma and an impressive tail. Comet C/2006 M4 (SWAN) was discovered in June in public images from the Solar Wind Anisotropies (SWAN) instrument of NASA and ESA's Sun-orbiting SOHO spacecraft. Comet SWAN, near magnitude six, will be visible with binoculars in the North-Eastern sky not far from the Big Dipper over the next few days before dawn. The comet is expected to reach its peak brightness this week. Passing its closest to the Sun two days ago, Comet SWAN and will be at its closest to the Earth toward the end of this month. Comet SWAN's unusual orbit appears to be hyperbolic, meaning that it will likely go off into interstellar space, never to return".
(8 voti)
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Itokawa-06.jpgOrbiting around Itokawa (3)53 visiteSpecifically, at the time of arrival at Itokawa, Hayabusa had driven its proprietary new ion engines for 26.000 hours, including their operation during an Earth flyby.
It has also perfectly completed a period of hybrid optical navigation followed by
precise guidance and navigation of the spacecraft during its station keeping period around Itokawa.
These engineering achievements are the primary mission of Hayabusa and their successful completion is a great achievement.
(8 voti)
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Itokawa-04.jpgOrbiting around Itokawa (1)53 visiteHayabusa arrived at its exploration target, near Earth asteroid Itokawa, on Sept., 12th, 2005 after having been propelled there via ion engines and an Earth swing-by. Since then, it has successfully performed orbital maneuvers, precisely keeping its position relative to Itokawa. The Hayabusa Project Team has made many discoveries while carrying out their ambitious scientific observations of Itokawa. This release summarizes and reports the major scientific and engineering achievements in advance of Hayabusa’s unprecedented and historic descent to the surfaceof Itokawa for sample collection middle to later this month (November 2005).
(8 voti)
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Itokawa~0.jpgClosing on Itokawa52 visiteItokawa: un asteroide che sembra contraddire tutto quanto viene dato per acquisito nel campo delle forme esteriori e dei rilievi superficiali dei corpi (teoricamente) esposti a pesantissimi azioni di impatto sin dagli albori della loro esistenza. Pensate a 433-Eros, oppure a Ceres, o Dactyl o a qualsiasi altro corpo similare che abbiamo avuto occasione di vedere da distanza ravvicinata. Forse il solo asteroide AnneFrank non sembra presentare una particolare craterizzazione (ma le immagini, di cattiva qualità, non possono essere considerate definitorie) e quindi si viene a porre nel novero delle rarità. Tuttavia, quello che vediamo adesso, è ben più che un'eccezione e molto di più di un'Anomalìa: Itokawa NON ha alcun cratere superficiale visibile e le sue forme, spigolose ed a tratti aguzze, costituiscono una novità assoluta per i Ricercatori e gli Studiosi di Scienze Planetarie.
Original caption:"Where are the craters on asteroid Itokawa? No one knows. The Japanese robot probe Hayabusa recently approached the Earth-crossing asteroid and is returning pictures showing a surface unlike any other Solar System body yet photographed -- a surface possibly devoid of craters. One possibility for the lack of common circular indentations is that asteroid Itokawa is a rubble pile -- a bunch of rocks and ice chunks only loosely held together by a small amount of gravity. If so, craters might be filled in whenever the asteroid gets jiggled by a passing planet -- Earth in this case. Alternatively, surface particles may become electrically charged by the Sun, levitate in the microgravity field, and move to fill in craters. Over the weekend, Hayabusa lowered itself to the surface of the strange asteroid in an effort to study the unusual body and collect surface samples that could be returned to Earth in 2007".
(8 voti)
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Itokawa.gifAsteroid "Itokawa": a new "shooting" against a Celestial Body53 visiteJapan's JAXA Space Agency launched the Hayabusa Mission to rendezvous with asteroid Itokawa. Last week, the small robotic Hayabusa spacecraft arrived at asteroid Itokawa and stationed only 20 Km away. Although a long term goal is to find out how much ice, rock and trace elements reside on the asteroid's surface, a shorter term goal is to determine the mass of the asteroid by measuring the attraction of the drifting Hayabusa spacecraft. During the next few months, Hayabusa will also image and map asteroid Itokawa. The above time-lapse image sequence was taken by Hayabusa upon final approach, showing the general oblong shape of the asteroid. In November, a small coffee-can sized robot dubbed MINERVA is scheduled for release and is expected to hop around the asteroid taking pictures. Also in November, Hayabusa will fire pellets into asteroid Itokawa and collect some of the debris in a return capsule. In December, Hayabusa will fire its rockets toward Earth and drop the return capsule in June 2007.
(8 voti)
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Tempel1-PIA07881.jpgTempel-1, from Kitt Peak (pseudo-colors)55 visiteCaption NASA originale:"The Kitt Peak National Observatory's 2,1-meter telescope observed comet Tempel 1 on April 11, 2005, when the comet was near its closest approach to the Earth. A pinkish dust jet is visible to the SouthWest, with the broader neutral gas coma surrounding it. North is up, East is to the left and the field of view is about 80.000 Km wide. The Sun was almost directly behind the observer at this time. The red, green and blue bars in the background are stars that moved between the individual images.
This pseudo-color picture was created by combining three black and white images obtained with different filters. The images were obtained with the HB Narrowband Comet Filters, using CN (3870 A - shown in blue), C2 (5140 A - shown in green) and RC (7128 A - shown in red).
The CN and C2 filters capture different gas species (along with the underlying dust) while the RC filter captures just the dust".
(8 voti)
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Asteroids_from_HST-01.jpgAsteroids, from HST (2)54 visite"Many asteroids remain undiscovered. In fact, 1 was discovered in 1998 as the long blue streak in the above archival image taken by the Hubble Space Telescope. In 2002 June, the small 100-mt asteroid 2002 MN was discovered only after it whizzed by the Earth, passing well within the orbit of the Moon. 2002 MN passed closer than any asteroid since 1994 XM1 but not as close as 2004 MN4 will pass in 2029. A collision with a large asteroid would not affect Earth's orbit so much as raise dust that would affect Earth's climate. One likely result is a global extinction of many species of life, possibly dwarfing the ongoing extinction occurring now".
Dopo aver letto questi commenti la nostra memoria ritorna allo tsunami del Dicembre 2004 ed al paventato spostamento dell'asse terrestre: l'ipotesi più plausibile per spiegare l'accaduto sembra essere proprio quella che la NASA stessa ci suggerisce commentando questi frames HST: un asteroide di circa 100 metri potrebbe aver impattato l'Oceano Indiano.
C'è da riflettere.
(8 voti)
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Comets-Wild_2-00.jpgApproaching Wild 2 (1)54 visiteCaption NASA originale:"This image was taken during the close approach phase of Stardust's Jan 2, 2004 flyby of comet Wild 2. It is a distant side view of the roughly spherical comet nucleus. One hemisphere is in sunlight and the other is in shadow analogous to a view of the quarter moon. Several large depressed regions can be seen. Comet Wild 2 is about 5 Km (3,1 miles) in diameter".
(8 voti)
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Comets-Wild_2-04.jpgThe map of Comet Wild 252 visiteUna mappa - non particolarmente dettagliata ma comunque idonea a farci vedere e riconoscere le aree maggiormente importanti - della Cometa Wild 2. La mappa in oggetto è stata ottenuta sulla base delle riprese della cometa effettuate dalla Sonda "Stardust" il 2 Gennaio 2004 e, in particolare, impiegando il frame che Vi mostriamo nel quadro successivo.
I nomi indicati per le diverse aree di Wild 2 sono quelli utilizzati dallo "Stardust Team".
Da notare, infine, che il "bacino Shoemaker" potrebbe (a dispetto delle apparenze) NON aver avuto origine da un impatto.
(8 voti)
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Comets-Comet_Churyumov-Gerasimenko-cometCG01_rosetta_2048-MF-EB-LXTT-IPF.jpgA view of Comet Churyumov-Gerasimenko218 visiteUn "piccolo" Tributo dato dalla prestigiosa rubrica quotidiana NASA "Astronomy Picture Of The Day" ai nostri Amici e Partner, Marco Faccin ed Elisabetta Bonora. Guardate su http :// apod. nasa. gov/ apod/ astropix.html di lunedì, 15 Settenbre 2014. Complimenti, di Cuore! E, sia detto per Onestà Intellettuale, qui, Lunexit, non c'entra nulla. Il nostro è solo un Omaggio a due OTTIMI Partners. Ma Lunexit, su questo Lavoro, non ha credito alcuno.MareKromium
(7 voti)
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Comets-Comet_Hyakutake.jpgComet Hyakutake55 visiteDa "NASA - Picture of the Day" del giorno 16 Dicembre 2009:"In 1996, an unexpectedly bright comet passed by planet Earth. Discovered less than two months before, Comet C/1996 B2 Hyakutake came within only 1/10th of the Earth-Sun distance from the Earth in late March. At that time, Comet Hyakutake, dubbed the Great Comet of 1996, became the brightest comet to grace the skies of Earth in 20 years. During its previous visit, Comet Hyakutake may well have been seen by the stone age Magdalenian culture, who 17.000 years ago were possibly among the first humans to live in tents as well as caves.
Pictured above near closest approach as it appeared on 1996 March 26, the long Ion and Dust Tails of Comet Hyakutake are visible flowing off to the left in front of a distant star field that includes both the Big and Little Dippers.
On the far left, the blue Ion Tail appears to have recently undergone a magnetic disconnection event. On the far right, the Comet's green-tinted Coma obscures a dense nucleus of melting dirty ice estimated to be about 5 Km across. A few months later, Comet Hyakutake began its long trek back to the outer Solar System.
Because of being gravitationally deflected by massive planets, Comet Hyakutake is not expected back for about 100.000 years...".MareKromium
(7 voti)
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ShootingStar.jpgShooting Star71 visiteDa "NASA - Picture of the Day" del giorno 15 Ottobre 2009:"The brilliant fireball meteor captured in this snapshot was a startling visitor to Tuesday evening's twilight skies over the city of Groningen (NL).
In fact, sightings of the meteor, as bright as the Full Moon, were widely reported throughout the Netherlands and Germany at approximately 17:00 UT. Accompanied by sonic booms and rumbling sounds, the meteor was seen to break up into bright fragments, eventually leaving a persistent smoke-like trail.
Even though there are bright fireball meteors in planet Earth's Atmosphere every day, sightings of them are relatively rare because they more often occur over oceans and uninhabited areas".MareKromium
(7 voti)
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