| Piú votate - Asteroids and Comets |
Itokawa-04.jpgOrbiting around Itokawa (1)58 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).
(9 voti)
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Itokawa.gifAsteroid "Itokawa": a new "shooting" against a Celestial Body58 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.
(9 voti)
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Tempel1-PIA07881.jpgTempel-1, from Kitt Peak (pseudo-colors)59 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".
(9 voti)
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Asteroids_from_HST-00.jpgAsteroids, from HST (1)68 visiteCaption NASA originale da "NASA - Picture of the Day" del 18 Aprile 2005:"Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor. Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing. Significant threats do exist for rocks near 100 meters in diameter, which strike the Earth roughly every 1000 years. An object this size could cause significant tsunamis were it to strike an ocean, potentially devastating even distant shores. A collision with a Massive asteroid, over 1 Km across, is more rare, occurring typically millions of years apart, but could have truly global consequences".
(9 voti)
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Comets-Wild_2-02.jpgWild 2 - stereo image pair59 visitenessun commento
(9 voti)
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Comets-Wild_2-05.jpgWild 262 visiteCaption NASA originale:"This image is the closest short exposure of the comet, taken at an 11,4° phase angle (phase angle is the angle between the camera, the comet and the Sun).
(9 voti)
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Comets-Wild_2-04.jpgThe map of Comet Wild 258 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.
(9 voti)
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Asteroids.jpgAsteroids (an Image-Mosaic by Emily Lakdawalla - Planetary Society - & Ted Stryk)104 visiteDalla Rubrica "NASA - Picture of the Day" del giorno 26 Luglio 2010:"As humans explore the Universe, the record for largest Asteroid visited by a Spacecraft has increased yet again. Earlier this month, ESA's robotic Rosetta Spacecraft zipped past the asteroid 21 Lutetia taking data and snapping images in an effort to better determine the history of the Asteroid and the origin of its unusual colors.
Although of unknown composition, Lutetia is not massive enough for gravity to pull it into a sphere.
Pictured above on the upper right, the 100-Km across Lutetia is shown in comparison with the other nine Asteroids and four Comets that have been visited, so far, by human-launched spacecraft. Orbiting in the Main Asteroid Belt, Lutetia shows itself to be a heavily cratered remnant of the early Solar System.
The Rosetta Spacecraft is now continuing onto comet Churyumov-Gerasimenko where a landing is planned for the AD 2014".MareKromium
(8 voti)
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Comets-Garrad-PIA12985.jpgComet Garradd57 visiteThis image from the WISE mission was taken on January 2nd, 2010, during the check-out phase, before the start of the WISE survey. It is a mosaic of 3 individual WISE frames spanning an area on the sky about 7 times the size of the full Moon in portions of the constellations Bootes and Canes Venatici.
In the lower right portion of the image there is a streak of orange light. This is most likely a human-made satellite, orbiting Earth at a higher altitude than the WISE telescope, which is at 523 km above the surface. WISE sees many of these as it scans the sky.
Just above the satellite in the image is Comet C/2008 Q3 (Garradd). Comets are balls of dust and ice left over from the formation of the Solar System. As a comet approaches the Sun it is heated and releases gas and dust from its surface that is blown back by the solar wind into a long, spectacular tail. This comet was discovered in August 2008 by Gordon Garradd of the Siding Spring Observatory in Australia. This comet probably comes from the Oort Cloud, a vast collection of remnants from the formation of the Solar System thought to surround it. At the time the comet was observed by WISE, in the constellation Bootes, it was a distance of 419 million kilometers (2.789 Astronomical Units, AU) from Earth. But we are just catching it while it is near the Sun. The orbit calculated for Comet C/2008 Q3 (Garradd) is inclined to the plane of the Solar System by nearly 140 degrees and takes it very far from the Sun (trillions of kilometers). It made its closest approach to the Sun in June of 2009 at a distance of 1.8 AU (270 million km), just outside the orbit of Mars. If it comes back near the Sun at all, it won't be for hundreds of thousands of years.
In the upper left of the image is the impressive globular cluster Messier 3 (M3). M3 was discovered in the constellation Canes Venatici by famous French Astronomer, Charles Messier in 1764, and first seen to be made of stars around 1784 by the British astronomer who discovered infrared light, William Herschel. Globular clusters are huge globs of stars (hence the name) that are found orbiting in the outer reaches of most galaxies. They are thought to form around the same time that a galaxy forms. The Milky Way has over 200 known globular clusters. M3 is one of the largest and brightest globular clusters around the Milky Way. It is just barely visible to the naked eye from a dark location. M3 is made of about half a million stars, thought to be about 8 billion years old. It is about 150 light-years across (1 light-year is equal to 9.46 trillion km) and located some 34,000 light-years from Earth.
WISE sees invisible infrared light, and the colors here are mapped to 3 of the 4 wavelength bands observed by WISE. Blue represents light with a wavelength of 3.4 microns, cyan maps to 4.6 microns and red is lightat 12 microns (a micron is 1 millionth of a meter, and visible light runs from 0.4-0.7 microns). The light from relatively hot objects, like stars in M3, is seen in blue and cyan. Red color represents cooler things, like dust from the comet and its tail. When this image was taken the WISE team was still calibrating the rate of the scan mirror with the motion of the WISE telescope. The rate was not yet perfected and careful examination of this image reveals some stars that are a little smeared and not exactly aligned in the blue/cyan with the red.
MareKromium
(8 voti)
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Comets-Comet_Siding_Spring-PIA12836.jpgComet Siding Spring61 visiteCaption NASA:"Is it a bird, or a plane? It's comet Siding Spring streaking across the sky, as seen by NASA's Wide-field Infrared Survey Explorer, or WISE.
The comet, also known as C/2007 Q3, was discovered in 2007 by observers in Australia. The snowball-like mass of ice and dust spent billions of years orbiting in the deep freeze of the Oort Cloud, a spherical cloud of comets surrounding our Solar System. At some point, it got knocked out of this orbit and onto a course that brings it closer to the Sun. Sunlight has warmed the Comet, causing it to shed ices and dust in a long tail that trails behind it.
On October 7, 2009, comet Siding Spring passed as close as 1,2 Astronomical Units from Earth and 2,25 Astronomical Units from the Sun (an Astronomical Unit - AU - is the distance between the Sun and Earth). Now, the comet is leaving the warmer, more hospitable neighborhood of the Solar System and heading back out to chillier parts. In this view, longer wavelengths of InfraRed Light are red and shorter wavelengths are blue.
The comet appears red because it is more than ten times colder than the surrounding stars. Colder objects give off more of their light at longer wavelengths.
An ice cube, for example, pours out a larger fraction of its light at longer InfraRed wavelengths than a cup of hot tea emits".MareKromium
(8 voti)
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ShootingStar.jpgShooting Star72 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
(8 voti)
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Asteroid_DD-45-b.gifAsteroid 2009 DD-45 (GIF-Movie)66 visiteVersione accelerata, leggermente ingrandita ed a contrasti amplificati della GIF-Movie che potrebbe aprire (anzi: che APRIRA'!) un autentico "caso ufologico": guardate e stupite!
...E complimenti al "mitico" Marco Faccin, anche lui puntuale come la Clock-Tower di Londra!MareKromium
(8 voti)
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