Tour of the Solar System: The Planet Jupiter

The great gas giant Jupiter orbits the sun just beyond the vaunted asteroid belt.  The planet is about 775 million KM from our Sun, and takes about 12 years to make just a single orbit.  On most nights, Jupiter can be readily seem in our night sky since it is one of the brightest objects.

There are 64 moons that have been cataloged as orbiting around the gas giant.  Jupiter's gravity produces a considerable amount of tidal forces on some of the moons that allow them to be quite warm, despite being located so far from our Sun.

Jupiter is thought to be mostly made up of liquids and gases.  However, deep within the bowels of the planet, a rocky core may be lurking that is surrounded by metallic hydrogen.

Late last summer, NASA launched the Juno spacecraft towards Jupiter.  It is expected to arrive on station in the summer of 2016. Juno will measure the amount of thermal radiation emanating from the gas giant.  Juno will also measure the magnetospere of Jupiter.

Jupiter has been long hypothesized as being a 'failed star.'  It contains the correct ingredients, about three quaters hydrogen and a quarter of helium,  as well as the same structure as a star.  However, it never quite reached the size, mass, and density to kick off steller ignition.

However, the planet does give off a little more heat than it receives from the Sun.  This total amount of heat given off is quite small and barely registers outside of its own atmosphere.  Since there is a low level of radiative steller process ongoing, the planet is shrinking by a few centimeters a year.