Logo

Archiv für Saturn

Ein Gürtel aus kleinen Monden

Das prächtige Ringsystem des Saturn geht auf die Zerstörung kleinerer Monde zurück. Für diese Theorie spricht nun auch die Entdeckung von acht Minimonden in einem der Saturnringe durch amerikanische, deutsche und finnische Forscher. Wahrscheinlich handelt es sich bei diesen Minimonden um Bruchstücke größerer Objekte, die allmählich durch Kollisionen mit anderen Brocken zermahlen wurden und so den Ring auffüllten. Die kleinen Monde dürften bestenfalls 140 Meter messen, schätzen Miodrag Sremcevic von der University of Colorado und seine Kollegen in einem Artikel im Fachmagazin “Nature”. Für ihre Untersuchungen wertete die Gruppe Aufnahmen der Raumsonde Cassini aus. Auf den Bildern sind die Winzlinge selbst zwar nicht zu sehen, sie verraten sich jedoch durch propellerförmige Dichteschwankungen des Ringmaterials in ihrer Nähe. Sieben der acht Minimonde liegen im A-Ring, dem äußeren der beiden hellsten und größten Saturnringe. Während der Ring etwa 14.000 Kilometer breit ist, befinden sich die sieben in einem 3.000 Kilometer schmalen Gürtel. Sie könnten auf das Auseinanderbrechen eines gut zehn Kilometer großen Mondes zurückgehen, schätzen die Forscher anhand der Gesamtmasse der großen Objekte im betreffenden Gürtel. Monde ähnlichen Kalibers ziehen noch heute um den Saturn, beispielsweise Pan und Daphnis. Der achte Minimond kreist knapp außerhalb der Encke-Teilung, einer Lücke im A-Ring, um den Saturn. Erst im letzten Jahr war über die ersten vier “Propeller” in dem Ringsystem berichtet worden. Eine weitere Studie über diese Objekte im A-Ring haben Carolyn Porco vom Space Science Institute in Boulder, Colorado, und ihre Kollegen kürzlich zur Begutachtung eingereicht.
New CU-Boulder Study Confirms First-Known Belt Of Moonlets In Saturn Rings

Propeller Belt

Ein Gürtel aus Minimonden

Four Propellers

The Alphabet Soup of Saturn’s Rings

Cassini's Diamond Anniversary

Ten years ago, NASA’s Cassini spacecraft departed planet Earth from Cape Canaveral, Florida, and embarked on a seven-year long, circuitous journey of several billion miles across the solar system to the planet Saturn. To celebrate this special occasion, the mission’s imaging team has released some stunning new images and movies of the ringed planet and its most photogenic companions:
http://ciclops.org/view_event.php?id=71

Cassini Pinpoints Hot Sources of Jets on Enceladus


A recent analysis of images from NASA’s Cassini spacecraft provides conclusive evidence that the jets of fine, icy particles spraying from Saturn’s moon Enceladus originate from the hottest spots on the moon’s “tiger stripe” fractures that straddle the moon’s south polar region.
Cassini Pinpoints Hot Sources of Jets on Enceladus

Possible Explanation for Two-Toned Iapetus

Saturn’s moon Iapetus is one of the most mysterious objects in the Solar System. It’s shaped like a walnut, with a strange ridge that runs along its equator, and it’s got vastly different hemispheres. One side is as white as snow, and the other side is dark as tar. Scientists think they’ve at least got an answer for this mystery.
Cassini is on the Trail of a Runaway Mystery

Inspiring Talk on Exploring the Saturn System

Planetary scientist Carolyn Porco is the leader of the Imaging Team for the Cassini mission. She gave an 18 minute talk on the Cassini-Huygens mission and on some of the amazing scientific results from Titan, Enceladus, and Saturn itself at the TED conference in Monterey in March 2007. Here is the video of that inspiring talk:

YouTube – Carolyn Porco: Fly me to the moons of Saturn

Link to this talk: http://www.ted.com/talks/carolyn_porco_flies_us_to_saturn

Frostiger Enceladus: Leben eher unwahrscheinlich

Ein neues Modell des Saturnmondes Enceladus könnte die Hoffnungen, dort Leben zu finden, dämpfen. Das von Forschern der Universität von Illinois erstellte Modell erklärt die auffallendsten Erscheinungen auf Enceladus ohne das Vorhandensein von flüssigem Wasser.
Frigid enceladus: an unlikely harbor for life

Cassini data points to origin of Saturn's G ring

Scientists studying data from NASA’s Cassini spacecraft have discovered what they thought is the origin for one of the more unusual rings surrounding the planet Saturn. In a paper published in the journal “Science”, they said Saturn’s G ring is likely linked to an arc of relatively large ice particles in a part of the ring’s inner edge, which are kept in line by the gravitational influence of Saturn’s moon Mimas. Collisions with micrometeoroids create smaller particles, which are then spread throughout the ring by plasma in Saturn’s magnetic field.
http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20070802/

Saturn’s Moon Iapetus Enjoys Eternal Youth

Saturn’s moon Iapetus is one of the strangest objects in our Solar System. Unlike other objects of this size, Iapetus is walnut-shaped, with a clearly defined chain of mountains along its equator. How could it have formed billions of years ago with the rest of the Solar System, and yet still have its unique shape? Researchers have developed a computer model that seems to accurately explain the series of events that Iapetus went through to arrive at its current shape. Billions of years ago, shortly after its formation, Iapetus spun quickly, taking just 5 hours to complete a rotation. This fast spin gave it the oblate walnut shape it has today. Over time, its rotation slowed down to about 16 hours. It also cooled down enough that its surface froze solid. It couldn’t absorb the excess surface material. Instead, this rubble built up the chain of mountains around its equator. At this point, its formation completely halted. The moon now orbits at a relatively slow rate, turning only once every 80 days. Scientists were able to confirm these computer model predictions for Iapetus, using observations of its rocks containing the short-lived isotopes aluminum-26 and iron-60. These decay at a rate that allowed scientists to carbon date the moon at roughly 4,564 billion years old.

http://www.jpl.nasa.gov/news/news.php?release=2007-079

Two More of Saturn’s Moons are Blasting Out Particles

One of Cassini’s greatest discoveries are the ice geysers pouring out of Saturn’s moon Enceladus. Recent research by the NASA/ESA Cassini team suggests that this icy moon isn’t the only geologically-active world orbiting the ringed planet. Two other Saturnian moons, Tethys and Dione, are shooting streams of charged particles into space, and this may be a sign of geysers like those on Enceladus.

http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens/Two_more_active_moons_around_Saturn

Clumps found in Saturn's rings

Scientists working with data from NASA’s Cassini spacecraft have concluded that one of Saturn’s major rings is composed of clumps of material rather than a more uniform distribution of smaller objects. Planetary scientists used a series of stellar occultations, where the rings passed in front of a star, to perform a “CAT scan” of the rings, analyzing the distribution of particles within them. They found that one ring, the B ring, contains tightly-packed clumps of material with wider spacings between the clumps than previously expected. The clumps are constantly forming and being town apart by Saturn’s gravity, often colliding with one another. This clumpiness may mean that Saturn’s rings are two to three times as massive as previously thought.
Cassini ‘Cat Scan’ Maps Clumps in Saturn’s Rings