In the foreground, Dione and pockmarked surface of impact craters and the background, there are the atmosphere of Saturn and its rings. The image was taken by Cassini August 17, 2015, 170,000 km from its surface when undertaking the last survey of its mission of this icy moon. © NASA, JPL-Caltech, Space Science Institute
Cassini offers us last image of Dione – 3 Photos
Arriving in 2004 in the kingdom of Saturn around which 62 known moons, the Cassini spacecraft, which left Earth 1997 will soon complete its mission. This Monday, August 17, 2015, she accomplished more than 1.4 billion km from us, his fifth and final overview of Dione, a moon that, precisely, was discovered in 1684 by Jean-Dominique Cassini (the astronomer named the four satellites he discovered “the stars of Louis” Sidera Lodoicea in honor of Louis XIV).
With a diameter of 1118 kilometers, Dione is rich in ice and recalls, in some ways, the dwarf planet Ceres (940 km) for its white spots she wears in multiple locations. Gravitationally bound to Saturn, its history, but is not quite the same.
Latest image captured by Cassini Dione, August 17 2015. The probe, then moving away, was 75,000 km from the surface of this little icy world. © NASA, JPL-Caltech, Space Science Institute
The nearest flyover, 100 km above the frozen ground date December 2011. Now Cassini is passed only 474 km from the surface. “We had just enough time to take some pictures, giving us beautiful views high resolution of its surface says Tilmann Denk (Freie University, Berlin), member of the scientific team mission. We have been able to use sunlight reflected from Saturn as additional light source, allowing to reveal details in the shadows of some images. “
But the visit was primarily an opportunity to perform one last time measurements of gravity and magnetosphere Dione. All collected data will help researchers better understand the structure of this icy planet.
Dione photographed by Cassini in 537 km of its surface, 17 August 2015. This is the image at the highest resolution of the mission to that moon of Saturn. © NASA, JPL-Caltech, Space Science Institute
NASA recalled in a statement that it remains for a Cassini handful of overflights to operate before completing its mission late 2017. One of his targets for next three appointments is Enceladus, another small icy moon. Since 2005 and the discovery of geysers, the body of some 500 km in diameter, geologically active and considered a potentially habitable worlds in the Solar System, focused much attention from scientists.
The ship Esa and Nasa will make a tour on 14 and 28 October and 19 December goodbye. On 28 October it be close Enceladus just 49 km above its surface, which represents a golden opportunity to creep into his steam jets, sniff and, of course, to probe that it contains (probably an ocean of liquid water in contact with its core).
“I am moved because I know, like everyone else, by watching these beautiful images of Dione and increasing its surface, it is the last of this distant world that we will see a very long time says Carolyn Porco, imaging team Space Science Institute (Boulder, Colorado). After Cassini has faithfully delivered another series of extraordinary wealth. What we were lucky … “
On the same subject
No comments:
Post a Comment