Callisto

 

Callisto is the second largest moon of Jupiter's known satellites .

 

 

Text Box: Discovered by Simon Marius & Galileo Galilei Date of discovery 1610 Mass (kg) 1.08e+23 Mass (Earth = 1) 1.8072e-02 Equatorial radius (km) 2,400 Equatorial radius (Earth = 1) 3.7629e-01 Mean density (gm/cm^3) 1.86 Mean distance from Jupiter (km) 1,883,000 Rotational period (days) 16.68902 Orbital period (days) 16.68902 Mean orbital velocity (km/sec) 8.21 Orbital eccentricity 0.007 Orbital inclination (degrees) 0.281 Escape velocity (km/sec) 2.45 Visual geometric albedo 0.20 Magnitude (Vo) 5.65  

Text Box: Orbit:1,883,000 km from Jupiter

 

 

 

Callisto is slightly smaller than Mercury and it is a third of its mass.  Callisto's surface is covered with craters and the oldest, most cratered surface observed in the solar system.  The largest crater is named Valhalla.  Vallhalla's central region is 600 kilometers in diameter and its rings reach out to 3000 kilometers in diameter.   Its crust is very ancient and goes back to 4 billion years ago.  It is possible that there is an ocean underneath the crust.  Callisto has no large mountains, which might be because of the icy surface.  It also seems that there are no earthquakes or volcanoes either  Callisto has no know atmosphere and its ancient craters collapsed like Ganymede. 

Text Box: Diameter: 4800 km

 

 

 

 

Text Box: Mass:1.08e23 kg