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Gemeenschappelijk 'donker' verleden voor manen van Saturnus?   Seen approximately as it would to the human eye, this image of Saturn's moon Dione was taken on 11 October 2005 by the NASA/ESA/ASI Cassini spacecraft. Blue, green and infrared (centred at 752 nanometres) spectral filters were used to create this colour view. The images were obtained with the Cassini spacecraft wide-angle camera at a distance of approximately 39 000 kilometres from Dione. The image scale is about 2 kilometres per pixel. Ecologie van het Saturnussysteem  This collage shows several of Saturn's moons.  Cassini captures the first high-resolution glimpse of the bright trailing hemisphere of Saturn's moon Iapetus. This false-color mosaic shows the entire hemisphere of Iapetus (1,468 kilometers) visible from Cassini on the outbound leg of its encounter with the two-toned moon in September 2007. The central longitude of the trailing hemisphere is 24 degrees to the left of the mosaic's center. Also shown here is the complicated transition region between the dark leading and bright trailing hemispheres. This region, visible along the right side of the image, was observed in many of the images acquired by Cassini near closest approach during the encounter. Revealed here for the first time in detail are the geological structures that mark the trailing hemisphere. The region appears heavily cratered, particularly in the north and south polar regions. Near the top of the mosaic, numerous impact features visible in NASA Voyager 2 spacecraft images (acquired in 1981) are visible, including the craters Ogier and Charlemagne. The most prominent topographic feature in this view, in the bottom half of the mosaic, is a 450-kilometer wide impact basin, one of at least nine such large basins on Iapetus. In fact, the basin overlaps an older, similar-sized impact basin to its southeast. In many places, the dark material - thought to be composed of nitrogen-bearing organic compounds called cyanides, hydrated minerals and other carbonaceous minerals - appears to coat equator-facing slopes and crater floors. The distribution of this material and variations in the color of the bright material across the trailing hemisphere will be crucial clues to understanding the origin of Iapetus' peculiar bright-dark dual personality. The view was acquired with the Cassini spacecraft narrow-angle camera on 10 September 2007, at a distance of about 73,000 kilometers from Iapetus. The color seen in this view represents an expansion of the wavelengths of the electromagnetic spectrum visible to human eyes. The intense reddish-brown hue of the dark material is far less pronounced in true color images. The use of enhanced color makes the reddish character of the dark material more visible than it would be to the naked eye. This mosaic consists of 60 images covering 15 footprints across the surface of Iapetus. The view is an orthographic projection centered on 10.8° south, 246.5° west and has a resolution of 426 metres per pixel. An orthographic view is most like the view seen by a distant observer looking through a telescope.
At each footprint, a full resolution clear filter image was combined with half-resolution images taken with infrared, green and ultraviolet spectral filters (centered at 752, 568 and 338 nanometres, respectively) to create this full-resolution false color mosaic. Donker materiaal van elders afkomstig  Det svenska visualiseringsverktyget UniView kan låta dig åka med ESA:s Cassini på en resa genom sarturnussystemet. UniView har sitt ursprung vid Linköpings universitet.  This is a composite image of Saturn's moon Phoebe comparing it in size with the Netherlands. Phoebe is, from top to bottom, 220 kilometres in height and 110 kilometres wide. The whole image of the Netherlands is 154 kilometres left to right, and 225 kilometres top to bottom. From the top of the fourth island to Hoek van Holland (north of where the delta starts), this distance is 220 kilometres.
But from Maastricht in the south (not in the picture) to its northernmost point, the Netherlands is 300 kilometres in length in total.  Surely one of the most gorgeous sights the solar system has to offer, Saturn sits enveloped by the full splendour of its stately rings in this mosaic of 36 images taken by Cassini over the course of about 2.5 hours, as the spacecraft scanned across the entire main ring system. This view looks toward the unlit side of the rings from about 40 °above the ring plane. Taking in the rings in their entirety was the focus of this particular imaging sequence obtained by the Cassini spacecraft’s wide-angle camera on 19 January 2007, at a distance of approximately 1.23 million kilometres from Saturn. Image scale is 70 kilometres per pixel. The camera exposure times were just right to capture the dark-side of its rings, but longer than that required to properly expose the globe of sunlit Saturn. Consequently, the sunlit half of the planet is overexposed. Between the blinding light of day and the dark of night, there is a strip of twilight on the globe where colourful details in the atmosphere can be seen. Bright clouds dot the bluish-grey northern polar region here. In the south, the planet's night side glows golden in reflected light from the rings' sunlit face.
Saturn's shadow stretches completely across the rings in this view, in contrast to what Cassini saw when it arrived in 2004. De ijspluimen van Enceladus  As it swooped past the south pole of Saturn's moon Enceladus on 14 July 2005, Cassini acquired high resolution views of this puzzling ice world. From afar, Enceladus exhibits a bizarre mixture of softened craters and complex, fractured terrains. This large mosaic of 21 narrow-angle camera images have been arranged to provide a full-disc view of the anti-Saturn hemisphere on Enceladus. This mosaic is a false-colour view that includes images taken at wavelengths from the ultraviolet to the infrared portion of the spectrum, and is similar to another, lower resolution false-colour view obtained during the flyby. In false-colour, many long fractures on Enceladus exhibit a pronounced difference in colour (represented here in blue) from the surrounding terrain. A leading explanation for the difference in colour is that the walls of the fractures expose outcrops of coarse-grained ice that are free of the powdery surface materials that cover flat-lying surfaces.
The original images in the false-colour mosaic range in resolution from 350 to 67 metres per pixel and were taken at distances ranging from 61 300 to 11 100 kilometres from Enceladus. The mosaic is also part of a movie sequence of images from this flyby.  This artist’s impression shows how the ice particles and water vapour observed spewing from geysers on Saturn's moon Enceladus may be related to liquid water beneath the surface. The large number of ice particles and the rate at which they are produced require high temperatures, close to the melting point of water. These warm temperatures indicate that there may be an internal lake of liquid water at or near the moon's south pole, where the geysers are present. This internal lake could be similar to Earth's Lake Vostok, where liquid water is locked in ice beneath Antarctica. The presence of liquid water inside Enceladus would have major implications for future studies of the possibility of life in the outer solar system. Achtergrond  An artist's impression of Huygens on Titan. Release date: 23 april 2008 |