|
|
Uranus-Hurricane01.jpgUranian Hurricane (detail 1)55 visitenessun commento
|
|
Uranus-Hurricane02.jpgUranian Hurricane (detail 2)54 visitenessun commento
|
|
Uranus-Neptune-HST3_.JPGUranus and Neptune, from HST (Natural Colors and Enhanced Natural Colors; credits: NASA)54 visitenessun commentoMareKromium
|
|
Uranus-Voyager2-PIA00369.jpgUranus Cloud Movement56 visiteTime-lapse Voyager 2 images of Uranus show the movement of 2 small, bright, streaky clouds - the first such features ever seen on the Planet. The clouds were detected in this series of orange-filtered images taken Jan. 14, 1986, over a 4.6-hour interval (from top to bottom). At the time, the spacecraft was about 12,9 MKM (about 8 MMs) from the Planet, whose pole of rotation is near the center of each disk. Uranus, which is tipped on its side with respect to the other planets, is rotating in a counterclockwise direction, as are the 2 clouds seen here as bright streaks.
(The occasional donut-shaped features that show up are shadows cast by dust in the camera optics. The processing necessary to bring out the faint features on the Planet also brings out these camera blemishes.) The larger of the 2 clouds is at a latitude of 33°; the smaller cloud, seen faintly in the 3 lower images, lies at 26° (a lower latitude and hence closer to the limb). Their counterclockwise periods of rotation are 16.2 and 16.9 hours, respectively. This difference implies that the lower-latitude feature is lagging behind the higher-latitude feature at a speed of almost 100 meters per second (220 mph). Latitudinal bands are also visible in these images. The faint bands, more numerous now than in previous Voyager images from longer range, are concentric with the pole of rotation -- that is, they circle the planet in lines of constant latitude.MareKromium
|
|
Uranus-familyportrait-PIA01975_modest.jpgThe 5 major moons of Uranus59 visiteThis "family portrait" of Uranus' 5 largest moons was compiled from images sent back Jan. 20, 1986, by Voyager 2 spacecraft. The pictures were taken through a clear filter from distances of 5 to 6,1 MKM (3,1 to 3.8 MMs). In this comparison, we see the relative sizes and relativities of the satellites. From left, in order of increasing distance from the planet, they are Miranda, Ariel, Umbriel, Titania and Oberon. The 2 largest, Oberon and Titania, are about half the size of Earth's Moon, or roughly, 1.600 Km (1.000 miles) in diameter. Miranda, smallest of the 5, has about one-quarter to one-third the diameter. Even in these distant views, the satellites exhibit distinct differences in appearance. On average, Oberon and Titania reflect about 20% of the sunlight, Umbriel about 12%, Ariel and Miranda about 30%. Ariel shows the largest contrast on its surface, with the brightest areas about 25%. All five satellites show only slight color variations on their surfaces, with their average color being very nearly gray. The best views of the satellites will be obtained Jan. 24, the day of closest approach.
|
|
Uranus-uppatm-PIA01488.jpgHaze in the upper atmosphere of Uranus57 visiteCaption NASA originale:"This is a computer enhancement of a Voyager 2 image, that emphasizes the high-level haze in Uranus' upper atmosphere. Notice how the clouds are obscured by the overlying atmosphere".
|
|
Uranus_and_Ariel.jpgUranus and Ariel: the Eclypse56 visiteCaption NASA originale:"This image is a never-before-seen astronomical alignment of a moon traversing the face of Uranus, and its accompanying shadow. The white dot near the center of Uranus' blue-green disk is the icy moon Ariel. The 700-mile-diameter satellite is casting a shadow onto the cloud tops of Uranus. To an observer on Uranus, this would appear as a solar eclipse, where the moon briefly blocks out the Sun as its shadow races across Uranus's cloud tops.
Though such "transits" by moons across the disks of their parents are commonplace for some other Gas Giant Planets, such as Jupiter, the satellites of Uranus orbit the planet in such a way that they rarely cast shadows on the Planet's Surface. Uranus is tilted so that its spin axis lies nearly in its orbital plane".
|
|
UranusandAriel-Eclypse.jpgUranus and Ariel; Earth and Moon55 visiteCaption NASA originale"This illustrates the relative sizes of Uranus, Earth and Earth's Moon. The images are shown at the proper relative size, but not the correct relative distance from each other. Uranus is approx. 31.000 miles (about 50.000 Km) in diameter, or about 4 times the size of Earth. The Earth is approx. 7.900 miles (about 12.800 Km) in diameter, or about 4 times the diameter of the Moon (2.100 miles, such as about 3.500 Km)".
|
|
UranusfromHST-1.JPGUranus, from HST (False Colors; credits: NASA)55 visitenessun commentoMareKromium
|
|
UranusfromHST-2.JPGUranus, from HST (Natural, but enhanced, Colors; credits: NASA)66 visitenessun commentoMareKromium
|
|
UranusfromHST-3.JPGUranus, from HST (Natural, but enhanced, Colors; credits: NASA)55 visitenessun commentoMareKromium
|
|
UranusfromHST-4.JPGUranus, from HST (Natural, but enhanced, Colors; credits: NASA)56 visitenessun commentoMareKromium
|
|
| 109 immagini su 10 pagina(e) |
 |
|
|
|
|
7 | |
|
|
