| Piú viste - Asteroids and Comets |
Comets-Comet_Holmes-UZ.gifThe Inner Coma of Comet Holmes60 visiteCaption NASA:"What's happening to Comet Holmes?
The rare comet remains visible to the unaided eyes of northern observers as an unusual small puff ball in the constellation of Perseus. A high resolution set of images of the comet's inner coma, taken last week and shown above, reveals significant detail. Close inspection shows numerous faint streamers that are possibly the result of jets emanating from the comet's nucleus. Comet Holmes has remained surprisingly bright over the past week, with luminosity estimates ranging from between visual magnitudes 2 to 3, making it brighter than most stars visible on a dark sky.
The above image of Comet Holmes was made with a small automated 0,38-meter telescope hirable over the web for a small fee".MareKromium
|
|
Asteroids-Asteroid_2002JF56-PIA09230-01.jpgFormer "Unknown Asteroid" is now "Asteroid 2002 JF56"60 visiteThe two "spots" in this image are a composite of two images of asteroid 2002 JF56 taken on June 11 and June 12, 2006, with the Multispectral Visible Imaging Camera (MVIC) component of the New Horizons Ralph imager. In the bottom image, taken when the asteroid was about 3,36 MKM (approx. 2,1 MMs) away from the Spacecraft, 2002 JF56 appears like a dim star. At top, taken at a distance of about 1,34 MKM (such as about 833.000 miles), the object is more than a factor of six brighter.
The best current, estimated diameter of the asteroid is approx. 2,5 Km.
The asteroid observation was a chance for the New Horizons team to test the spacecraft's ability to track a rapidly moving object. On June 13 New Horizons came to within about 102.000 Km of the small asteroid, when the Spacecraft was nearly 368 MKM (about 228 MMs) from the Sun and about 273 MKM (approx 170 MMs) from Earth.MareKromium
|
|
EROS-GIFMovie-051.gif433-Eros: features in motion! (GIF-Movie; credits: Dr G. Barca)60 visitenessun commentoMareKromium
|
|
Comets-Comet_Lulin-00.jpgComet Lulin is approaching...60 visiteDa "NASA - Picture of the Day", del giorno 2 Febbraio 2009:"How bright will Comet Lulin become? No one knows for sure. Although it is notoriously difficult to accurately predict the brightness of newly discovered comets, Comet Lulin could well become visible to the unaided eye later this month (such as February 2009).
As Comet Lulin moves into the Northern Sky in mid February to rise around midnight, it should at least be spotted by comet watchers with binoculars and a good sky chart. Tracking observations indicate that the comet officially designated C/2007 N3 (Lulin) has now swung by the Sun and is approaching Earth on a trajectory that will bring it within half the Earth-Sun distance in late February.
Comet Lulin's orbit indicates that this is likely the comet's first trip into the Inner Solar System. The comet was discovered by Quanzhi Ye of Sun Yat-sen University, on images obtained by Chi-Sheng Lin at the Lu-Lin Observatory of National Central University.
In this picture, taken from Italy last Friday, are Comet Lulin's coma and tails, one tail pointing away from the Sun, and an anti-tail - dust that trails the comet in its orbit and may appear to point toward the Sun".MareKromium
|
|
Comets-Comet_Lulin_05.jpgComet Lulin and distant Galaxies60 visiteCaption NASA, da "NASA - Picture of the Day" del giorno 7 Marzo 2009:"Now fading in our night sky, Comet Lulin has provided some lovely cosmic vistas. Moving rapidly against the background of stars, Lulin briefly posed with the likes of Saturn and Regulus (Alpha Leo).
But here it is seen against a field of distant galaxies. To reveal the faint background galaxies and trace the Comet's fading tail, the remarkable picture is a blended composite of telescopic exposures aligned with the both the stars and the speedy comet. The largest galaxies seen left of the comet's head or coma are cataloged as NGC 3016, NGC 3019, NGC 3020 and NGC 3024 and lie at a distance of 100 MLY or so.
When the exposures were made, on February 28, the Lulin was about 3,6 Light-Minutes from Earth".MareKromium
|
|
Comets-Comet_Hyakutake.jpgComet Hyakutake60 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
|
|
KBO-1-Artist_Conception.jpgKuiper's Belt Object occulting a Star60 visiteThis is an artist's impression of a 0,5-mile-diameter Kuiper Belt Object (KBO) that was detected by NASA's Hubble Space Telescope. The icy relic from the early Solar System is too small for Hubble to photograph. The object was detected when it passed in front of a background star, temporarily disrupting the starlight.MareKromium
|
|
Itokawa.gifRevolving around Itokawa (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)60 visitenessun commentoMareKromium
|
|
DACTYL-PIA00298.jpgAsteroid Dactyl59 visiteWithin seconds of its closest approach to the asteroid 243 Ida on August 28, 1993, the Galileo spacecraft's Solid State Imaging camera caught this glimpse of Ida's previously unknown moon orbiting the asteroid. One frame of a 15-image set designed to capture a view of Ida at the highest possible resolution landed by chance with its edge right on the little moon. The range from the spacecraft was about 2.400 Km and each picture element spans about 24 meters (80 feet) on the surface of the moon. Only a small sliver of the sunlit crescent is visible at the edge of the frame (which was shifted inward toward the center in this frame). Dactyl is approximately egg-shaped, measuring about 1.2 x 1.4 x 1.6 Km (0.75 x 0.87 x 1 mile). At the time this image was shuttered, Ida was about 90 Km (56 miles) away from the moon, outside this frame to the left and slightly below center. The smoothly curving shape of the dark edge of Ida's moon can be seen on the left. The moon's observed darkside was just barely detectable.
|
|
IDA-PIA00135.jpgAsteroid Ida (HR)59 visiteThis view of the asteroid 243 Ida is a mosaic of 5 image frames acquired by the Galileo spacecraft's solid-state imaging system at ranges of 3.057 to 3.821 Km on August 28, 1993, about 3-1/2 minutes before the spacecraft made its closest approach to the asteroid. Galileo flew about 2.400 Km from Ida at a relative velocity of 12.4 km/sec (28,000 mph). Asteroid and spacecraft were 441 million Km from the Sun. Ida is the second asteroid ever encountered by a spacecraft. It appears to be about 52 Km in length, more than twice as large as Gaspra, the first asteroid observed by Galileo in October 1991. Ida is an irregularly shaped asteroid placed by scientists in the S class (believed to be like stony or stony iron meteorites). It is a member of the Koronis family, presumed fragments left from the breakup of a precursor asteroid in a catastrophic collision. This view shows numerous craters, including many degraded craters larger than any seen on Gaspra.
|
|
EROS-PIA02906_modest.jpgHorizon view59 visiteThis image of Eros, taken from the NEAR Shoemaker spacecraft on May 2, 2000, from an orbital altitude of 52 kilometers (32 miles), shows a view toward Eros' horizon. The section shown is about 1.8 kilometers (1.1 miles) across. This particular view provides a snapshot of three of the most common types of features seen on the asteroid: craters whose rims have been rounded by erosion due to smaller impacts and blanketing by the impact debris, or regolith (impact debris); variations in the brightness of material on the walls of the craters; and a scattering of boulders ranging in size from nearly 100 meters (328 feet) down to about 8 meters (26 feet).
|
|
Comets-Wild_2-04.jpgThe map of Comet Wild 259 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 รจ 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.
|
|
| 282 immagini su 24 pagina(e) |
 |
|
|
|
|
13 | |
|
|
|
|
