Io ( "EYE oh" ) is the fifth of Jupiter 's known satellites and the third largest; it is the innermost of the Galilean moons. ... Discovered by Galileo and Marius in 1610. ... Io's surface is radically different from any other body in the solar system. ... The material erupting from Io's vents appears to be some form of sulfur or sulfur dioxide. ... Analysis of the Voyager images led scientists to believe that the lava flows on Io's surface were composed mostly of various compounds of molten sulfur. ...

... B efore the Galileo encounters with Ganymede it was thought that Ganymede and Callisto were composed of a rocky core surrounded by a large mantle of water or water ice with an ice surface (and that Titan and Triton were similar). ... G anymede's surface is a roughly equal mix of two types of terrain: very old , highly cratered dark regions (left), and somewhat younger (but still ancient) lighter regions marked with an extensive array of grooves and ridges (right). ... Callisto .. ...

Ganymede . ... Ganymede Statistics . ... Hubble Finds Ozone on Jupiter's Moon Ganymede . ... Like Callisto , Ganymede is most likely composed of a rocky core with a water/ice mantle and a crust of rock and ice. ... Ganymede's mantle is most likely composed of ice and silicates, and its crust is probably a thick layer of water ice. ... Ganymede's surface is rich in water ice and Voyager and Galileo images show features which are evidence of geological and tectonic disruption of the surface in the past. ...

Giant Jupiter. Jupiter . ... Jupiter has no solid surface that is why speaking about its dimensious point the radius of the upper border line of the clouds, where the presseru is about 10 KPa; radius of Jupiter on the equator is 71400 km. ... The Jupiter satellites. ... Nowadays 16 satellites of the Jupiter are known: Adrastea, Mitis, Amaltea , Phina,then 4 Galilei satellites: Io , Europe , Hanimed , Callisto , Leda, Aimalia, Zicitea, Elara, Ananke, Carme, Pasipe and Sinope. ... Jupiter's ring. ...

... In summer 1994, the biggest news in astronomy was the collision of comet Shoemaker-Levy 9 with Jupiter. During this school year, Jupiter will charge back into the limelight with the arrival of the Galileo spacecraft (see figure 8 ). On Dec. 7, following a tortuous six-year ramble through the solar system, Galileo will begin its two-year mission studying Jupiter and its gaggle of moons. ... Besides the camera, Galileo will carry instruments capable of identifying minerals on Jupiter's moons. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Bad Astro Store . ... Site Info . ... It is from from Voyager 1 and shows a whopping big impact crater dominating the profile of the moon. Note that Mimas is about 400 kilometers across (about 250 miles). ... The wall around the crater is 5 kilometers high, and that central peak rises 6 kilometers above the surface (many impact craters have a large central peak which is caused by a pressure rebound from the impact). ... 2008 Phil Plait. ...

... Black Hole Signature From Advective Disks . ... If alone, a black hole would indeed appear quite black, but many black hole candidates are part of binary star systems. So how does a black hole binary system look different from a neutron star binary system? ... Sunspots: Magnetic Depressions . ... Our Sun has spots! These spots appear dark in photographs like the one above, but in fact sunspots are quite bright - they are just dark compared to the rest of the Sun. ... Blue Sun Glaring . ...

... Magnetic fields, subatomic particles, etc., traveling in different directions fill the universe. Do they deflect or otherwise affect one another? If so, isnт??t the information we get from them distorted? ... Neutrino astronomy, which is still in its infancy, is attractive because neutrinos interact so weakly with matter that few of these distorting effects occur. Get instant access to subscriber content on Astronomy.com! ...

NATIONAL ASTRONOMY AND IONOSPHERE CENTER . ... Astronomy . ... Visitor Center . ... Planetary Radar . ... A program of delay-Doppler mapping of the Galillean satellites is underway by L. Harcke and colleagues at Stanford University. The surfaces of Europa, Ganymede and Callisto have been imaged in order to determine the surface properties and look for different radar properties of the various terrain types. These maps will be correlated with the Galileo images of the satellites.€а . ...

Astronotes Armagh Planetarium's Stellar Blog! ... Planets . ... Monthly Sky Notes . ... October . ... By admin October 8, 2010 Posted in: Monthly Sky Notes . A giant from close up: an image made using data from the Cassini probe which flew past Jupiter in 2000. ... As it is so far from us, it takes JupiterтАЩs light a significant time to reach us тАУso when you see Jupiter tonight you are seeing it as it was 35€а minutes in the past. ... Posted October 12, 2010 at 11:15 PM . ... Astronotes . ...

FAMILIES AND SCATTERING . ... An important observation on the orbital distribution of irregular satellites is that satellite families at Saturn, Uranus and Neptune are not well defined. At Jupiter one finds 3-4 reasonably compact retrograde families, corresponding to each of the previously known retrograde irregulars and one prograde family. ... That is contrary to the current doctrine that very little has happened to these irregular satellite families following their collisional formation. ...

... Magnetic Storms . ... The Earth's own magnetic field is probably created in the Earth's core, believed to contain molten iron, by a "fluid dynamo" . ... Jupiter . ... The magnetospheres of the giant planets differ from the Earth's in at least four ways. ... If Jupiter's magnetosphere has the same proportions, the solar wind would need 2-3 days to cover the corresponding distance (equal to about half the Earth-Sun distance!), during which the planet might have rotated 5-7 times around its axis. ...