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    Jupiter is the closest "gas giant" planet to the sun.  It is also the largest planet in our solar system, and because of that, named after the most powerful god in Roman mythology (Zeus in Greek mythology).  This planet was also known to the ancients as separate from the stars.  Through our two telescopes, Jupiter is very interesting.  On a dark night, the bands across the planet are visible, along with the four Galilean moons: Io, Europa, Ganymede, and Callisto.  Occasionally, we can even see the famous great red spot, a huge hurricane on Jupiter which has been blowing for over 400 years, in which 3 Earths would fit!  Here are some more fun facts about Jupiter:


Mass -- 1.8987 x 1027 kg   (317.82 earth masses)


Radius -- 44,423 mi   (71,492 km or 11.209 earth radii)


Distance from the sun (average) -- 483,682,810 mi   (778,412,020 km or 5.023 AU)


Gravity -- 68.48 ft/sq. sec   (20.87 m/sq. sec)

    An adult weighing 140 lbs on Earth would weigh 298 lbs on Jupiter!


Orbital velocity -- 29.236 mph   (47,051 km/hr or 0.0439 earth speed)


Orbital eccentricity -- 0.04839

    This is how off-circular the moon's orbit around the Earth is.  An eccentricity of 0.00 would be a perfect circle.  An eccentricity of nearly 1 would be a very flattened oval.  For a fun project on ellipses and eccentricity, click here.


Sidereal rotation -- 9.925 hr   (0.4147 earth days)

    A day on Jupiter is less than half an Earth day.


Sidereal orbit -- 103,934 hr   (4,330 earth days or 11.9 earth years)

    Jupiter's year is nearly 12x the length of a year on Earth.


Moons -- 60+, including Io, Europa, Ganymede, and Callisto

    Astronomers are constantly finding new moons with the ever-increasing available technology.



For more information on Jupiter, please visit SEDS' website and NASA's website  Both websites are wonderful resources. 


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Website last updated March 16,  2006.  Hosted by Anthony Watts, KMXI Radio.  Webmasters Tiara Norris and Brendan Diamond.