[EN VIDÉO] Saturn: the giant with the rings of ice and dustEmbark on a journey to meet the second largest planet in the Solar System: Saturn. A gas giant surrounded by a multitude of brilliant rings that does not leave anyone indifferent when observed. Get to know the world of Saturn, explored very closely for 13 years by the Cassini probe.
It is up to the astronomer, mathematician and physicist Dutch Christian Huygens (1629-1695) that we owe the discovery of the rings of Saturn in 1655. To tell the truth, they had been observed well in astronomical telescopes since Galileo but nobody until Huygens had clear observations highlighting their nature and it was also he who drew from his interpretation of the existence of rings around Saturn a prediction that would be verified and that would convince his colleagues: observation by the edge of these rings in 1671.
Until the 1970s, only the rings of Saturn were known, but in 1979 the Voyager 1 probe revealed the rings of Jupiter. In 1989, the probe Voyager 2 will make it possible to photograph for the first time the rings of Neptune whose existence had been demonstrated in 1984 thanks to the observation program ofconcealment ofstars proposed by André Brahic and his colleagues, Bruno Sicardy and Françoise Roques from the Paris-Meudon Observatory, and produced by Patrice Bouchet, Reinhold Häfner and Jean Manfroid at the La Silla Observatory (ESO).
In fact, rings aroundUranus had already been discovered by chance on March 10, 1977 by James L. Elliot, Edward W. Dunham and Douglas J. Mink from observations carried out using the Gerard P. Kuiper Airborne Observatory (KAO; in French “Gerard P. Kuiper Airborne Observatory”) which was a project of the Nasa to develop research in astronomy infrared.
But back to the rings of Jupiter. The Jovian ring system is tenuous and mostly composed of dust and not ice unlike that of Saturn and these reasons explain why it took so long to detect it. It is divided into several rings: the halo, the main ring and the Gossamer rings. In particular, it was studied using the telescope Hubble and probes Galileo and Juno.
We do not yet know the origin of the rings of Saturn, nor when they date. This is an open research topic, and symmetrically, we wondered why Jupiter, which is a little more massive and larger than Saturn, does not have a comparable ring system. Of them astronomers from UC Riverside in the USA have filed on arXiv an article in which they propose an answer to this enigma.
In a statement from the University, one of the authors of the article, Stephen Kaneexplain that ” that [l]It’s long bothered that Jupiter doesn’t have even more amazing rings that would put Saturn to shame. If Jupiter had them, they would appear even brighter to us, because the planet is so much closer than Saturn. “. This led the researcher to wonder if Jupiter would not have had rings in the past, rings which would have disappeared due to instability specific to celestial mechanics with its gravitational disturbances, its tidal forces and his resonances gravitational.
The computers modern and the refinements of the simulations of the consequences of the laws of theastrophysics that they allow have therefore been taken advantage of by Stephen Kane and his doctoral student Zhexing Li to find out for sure. The two men therefore sought the effects that the four moons principals of Jupiter, IoEurope, Ganymede and Callisto on rings around Jupiter.
The results were not long in coming, as Kane again explained in a press release: We discovered that the Galilean moons of Jupiter, one of which is the largest moon of our solar systemwould very quickly destroy any large rings that might form “.
The rings of Jupiter that we know are therefore for this reason very little massive and it is thought that they are regularly supplied with dust by collisions of micrometeorites on other smaller moons of Jupiter, such as Thebe, Amalthea and especially Adrastea and Metis.
JupiterColor mosaic made up of 27 images taken from nine locations (in red, green and blue) by the Cassini-Huygens probe on December 29, 2000, when it was 10 million km from Jupiter. This is the finest portrait of Jupiter ever made, which allows you to view details, the smallest of which measure 60 km.
Shoemaker-Levy impact on JupiterPhoto taken in July 1994, just after the impact.
Io and Jupiter from Cassini
Jupiter and its system
Eruption on IoIncredible images of an eruption on Io in the Tvashtar region
The pack ice on Europe 1
The pack ice on Europe 2
Eruption on Io: Tvashtar regionLava fountains in the caldera of the Tvashtar region.
Ice Cliffs in Europe
Models of the structure of Europe
Volcanic plumes on Io
Evolution of volcanic plumes on Io
Evolution of the ground on Io
Important volcanic areas on Io
Comparison of the main satellites of Jupiter (surfaces)
Comparison of the main satellites of Jupiter
Comparison of Io and AmaltheIn this image we compare the size of two moons of Jupiter. Note the similarity in color which possibly implies that Amalthe owes its color to sulfur plumes ejected by Io.
Lava fountains on Io
The volcanic region of Tvashtar
Recent sinking on IoThe image shows, in dark, a recent flow on Io, covering an older deposit area (?). For more: http://photojournal.jpl.nasa.gov/catalog/PIA02557
Sodium clouds surrounding IoThis image taken with filters shows the gaseous envelope of sodium and sulfur from eruptions on Io For more: http://photojournal.jpl.nasa.gov/catalog/PIA01111