| Ultimi arrivi - Saturn: the "Ringed Beauty" and His Moons |
Mimas-PIA08172.jpgMimas, from 190.000 Km57 visiteThis amazing perspective view captures battered Mimas against the hazy limb of Saturn.
It is obvious in such close-up images that Mimas (397 Km, or about 247 miles across) has been badly scarred by impacts over the eons. Its 130 kilometer- (80 mile-) wide crater, Herschel, lies in the darkness at right.
North on Mimas is up and rotated 19° to the right.
The image was taken with the Cassini spacecraft narrow-angle camera on March 21, 2006 using a filter sensitive to wavelengths of ultraviolet light centered at 338 nnmts. The image was acquired at a distance of approximately 191.000 Km (approx. 119.000 miles) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 91°. Image scale is about 1 Km (such as approx. 3.730 feet) per pixel.Mag 05, 2006
|
|
Janus and Epimetheus-PIA08170.jpgJanus, Epimetheus and the "Orbital Switch"57 visiteCaption NASA originale:"In their orbital ballet, Janus and Epimetheus swap positions every four years - one moon moving closer to Saturn, the other moving farther away. The two recently changed positions (the swap occurring on January 21, 2006), and Janus will remain the innermost of the pair until 2010, when they will switch positions again.
Although the moons appear to be close in the image, they are not. Janus is about 40.000 Km (appx. 25.000 miles) farther away from Cassini than Epimetheus (at left) in this view. In fact, even when they are at their closest, tugging at each other and swapping orbital positions, they are never closer than about 15.000 Km (about 9.000 miles).
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 20, 2006 at a distance of approx. 452.000 Km(about 281.000 miles) from Epimetheus and 492.000 Km (about 306,000 miles) from Janus. The image scale is about 3 Km (appx. 2 miles) per pixel on both moons".Mag 03, 2006
|
|
Janus-PIA08169.jpgJanus and the Rings58 visiteCaption NASA originale:"Janus peeks out from beneath the Ring-Plane, partially lit here by reflected light from Saturn. A couple of craters can be seen on the moon's surface. To the right, two faint clumps of material can be seen in the dynamic F-Ring.
The perspective in this view may be a bit confusing -- from just below the Ring-Plane, Cassini is gazing toward Janus (181 Km, or 113 miles across), which is behind the Rings.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 16, 2006, at a distance of approx. 2,1 MKM (such as about 1,3 MMs) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 103°. Image scale is approx. 12 Km (about 8 miles) per pixel".Mag 03, 2006
|
|
Pan-N00060357.jpgSinking in the Rings: Pan, from 438.000 Km57 visiteCaption NASA:"N00060357.jpg was taken on April 29, 2006 and received on Earth April 29, 2006. The camera was pointing toward Pan that, at the time, was approximately 438.027 Km away.
The image was taken using the CL1 and CL2 filters. This image has not been validated or calibrated"Mag 01, 2006
|
|
Janus-N00060322.jpgLonely Janus...73 visiteCaption NASA:"N00060322.jpg was taken on April 29, 2006 and received on Earth April 29, 2006. The camera was pointing toward Janus that, at the time, was approximately 225.386 Km away.
The image was taken using the P120 and GRN filters. This image has not been validated or calibrated".Mag 01, 2006
|
|
Janus-N00060306.jpgThe "Runners": Janus and Epimetheus58 visiteCaption NASA:"N00060306.jpg was taken on April 29, 2006 and received on Earth April 29, 2006. The camera was pointing toward Janus that, at the time, was approximately 217.624 Km away.
The image was taken using the CL1 and CL2 filters. This image has not been validated or calibrated".Mag 01, 2006
|
|
Saturn-PIA08166.jpgRomantic inhospitality...61 visiteCaption originale:"Dreamy colors ranging from pale rose to butterscotch to sapphire give this utterly inhospitable gas planet a romantic appeal. Shadows of the rings caress the Northern Latitudes whose blue color is presumed to be a seasonal effect.
Enceladus hugs the Ring-Plane right of center.
Images taken using red, green and blue spectral filters were combined to create this color view, which approximates what the human eye would see. The image was taken with the Cassini spacecraft wide-angle camera on March 16, 2006 at a distance of approximately 2,1 MKM (such as about 1,3 MMs) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 102°. Image scale is about 120 Km (approx. 75 miles) per pixel on Saturn".Apr 27, 2006
|
|
Tethys&Co-PIA08165.jpgWonderful Trio, in Saturn's Space58 visiteCaption originale:"The three very different moons seen here provide targets of great interest for planetary scientists studying the Saturn System. Captured here by Cassini, along with the Rings, are Tethys at upper right, Enceladus below center and Janus at lower left.
Researchers study the orbital dance of Janus (181 Km, or about 113 miles across) with Epimetheus, tectonics and cratering on Tethys (1.071 Km, or approx. 665 miles across) and geyser activity on Enceladus (505 Km, or about 314 miles across). And these are only a few of the wonders that await exploration in the realm of the Ringed Planet.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 16, 2006, at a distance of approx. 2,4 MKM (such as about 1,5 MMs) from Tethys; 1,9 MKM (about 1,2 MMs) from Enceladus and 2,2 MKM (roughly 1,4 MMs) from Janus. The image scale is about 14 Km (appx. 9 miles) per pixel on Tethys, 11 Km (about 7 miles) p. px. on Enceladus and 13 Km (about 8 miles) p. px on Janus".Apr 26, 2006
|
|
The Rings-PIA08163-2.jpgThe "E-Ring" of Saturn: the "Enceladus Ring" (2)58 visiteThis appearance implies that the particles in this part of the Ring have nonzero inclinations (a similar affect is seen in Jupiter's Gossamer Ring). An object with a nonzero inclination does not orbit exactly at Saturn¿s Ring-Plane: its orbit takes it above and below it. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus. One possible explanation is that all the E-Ring particles come from the plume of icy material that is shooting due South out of the moon's Pole.
This means all of the particles are created with a certain velocity out of the Ring-Plane, and then they orbit above and below that plane.
Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally scatters any particles that lie very close to the Ring-Plane, giving them nonzero inclinations. Stray light within the camera system is responsible for the broad, faint "Y" shape across the image.
The image was taken in visible light with the Cassini spacecraft wide-angle camera on March 15, 2006, at a distance of approximately 2.4 million kilometers (1.5 million miles) from Saturn. The image scale on the sky at the distance of Saturn is 142 kilometers (88 miles) per pixel.
Apr 26, 2006
|
|
The Rings-PIA08163-1.jpgThe "E-Ring" of Saturn: the "Enceladus Ring" (1)67 visiteThis excellent view of the faint E-Ring - a ring feature now known to be created by Enceladus - also shows two of Saturn's small moons that orbit within the Ring, among a field of stars in the background.
The E-Ring extends from three to eight Saturn radii - about 180.000 Km(such as about 118.000 miles) to 482.000 Km (about 300.000 miles). Its full extent is not visible in this view.
Calypso (22 Km, or about 14 miles across) and Helene (32 Km, or about 20 miles across) orbit within the E-Ring's expanse. Helene skirts the outer parts of the E-Ring, but here it is projected in front of a region deeper within the Ring.
Calypso and Helene are trojan satellites, or moons that orbit 60° in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione. An interesting feature of note in this image is the double-banded appearance of the E-Ring, which is created because the Ring is somewhat fainter in the Ring-Plane than it is 500-1000 Km (about 300-600 miles) above and below it.Apr 26, 2006
|
|
Saturn-PIA08162.jpgSaturnian (swirling) clouds61 visiteCaption NASA originale:"The bright whorls and small-scale specks of convective clouds drift through a Region just North of Saturn's bright Equatorial Band. Observers have seen major storms develop in this Region in the past 15-20 years.
The image was taken in visible red light with the Cassini spacecraft narrow-angle camera on March 13, 2006, at a distance of approximately 2,6 MKM (about 1,6 MMs) from Saturn. The image scale is approx. 15 Km (about 9 miles) per pixel".Apr 24, 2006
|
|
Rhea-PIA08148.jpgRhea (HR)86 visiteCaption NASA originale:"Rhea shows off her bright, fresh-looking impact crater in this Cassini view taken during a close approach. The view is toward the Leading Hemisphere on Rhea. North is up.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 24, 2006 at a distance of approx. 343.000 Km (such as about 213.000 miles) from Rhea and at a phase angle of 27°. Image scale is 2 Km (about 1 mile) per pixel".Apr 22, 2006
|
|
| 2245 immagini su 188 pagina(e) |
 |
|
|
|
|
108 | |
|
|
|
|
