Jupiter is one of the most studied astronomical objects.  Jupiter is by far the largest planet in our Solar System, with more than twice the mass of all the other planets combined.  In fact, it has 318 times the mass of the Earth.  It's one of the brightest objects in the night sky and people have been studying it since before anyone knew what planets were.  Galileo first examined Jupiter with a telescope and discovered four of its moons in 1610.  Since that time, thousands of astronomers have studied the mysterious planet.  Radio emissions from Jupiter were detected in the 1950s.  Scientists soon realized that Jupiter had an enormous magnetic field where trapped electrons and protons spiraled back and forth, producing radio waves called synchrotron emission.  Voyager 1 and Voyager 2 flew by Jupiter in 1979 and the Galileo spacecraft orbited Jupiter from 1995 to 2003, sending a probe into the giant planet to study its atmosphere and returning a steady stream of data about the giant planet and the entire Jovian system.  Ulysses used Jupiter's enormous gravitational pull for an assist to change its trajectory into an orbit over the Sun's poles and Cassini gave us more data as it flew by Jupiter in 2000 on the way to Saturn. 
Even though we know a lot about Jupiter, in many ways it still remains a mystery.  It has more than 60 moons and several rings.  Scientists have plotted the orbits of the moons and studied the rings.  We've found tantalizing hints of liquid water below the icy surface of Jupiter's moon Europa but we don't yet know if it could harbor life.  We've discovered volcanoes on Io's surface and deduced how stresses from Jupiter's enormous gravity are heating that fiery Jovian satellite.

Jupiter presents a fascinating set of mysteries for scientists to unravel and in many ways it is the key to understanding our Solar System and how planets form.  Over the coming decade, scientists will answer many of the questions posed by our Solar System's largest planet.  GAVRT students will be part of the science team making important contributions as we solve fundamental puzzles posed by the mysterious giant, which dominates our planetary neighborhood.


GAVRT has been accepted as an educational partner in the upcoming NASA mission, Juno.  Juno is a Jupiter polar orbiter, which is scheduled to launch in 2011 and to arrive at Jupiter in 2016.  For a year, Juno will orbit Jupiter every 11 days as it attempts to probe the interior of Jupiter.  By precisely mapping the magnetic field close to the planet, Juno will help us understand the magnetic dynamo, which must lie deep inside the giant planet.  Using Doppler measurements of the spacecraft's orbital velocity as it closely orbits the planet at 32 different longitudes, Juno will determine the gravitational field and learn still more about the interior structure.  We will also be measuring the mass of Jupiter's solid core (if it has one) and improving our understanding of the belts and zones.  Juno will use radiometers at six different microwave frequencies to penetrate deep into the Jovian atmosphere, measuring the global water/oxygen abundance, which is crucial to understanding how and where the planet formed.  The microwave observations will also yield valuable information about the dynamics of Jupiter's atmosphere, helping us solve the many puzzles of Jupiter's weather and atmospheric system.  Juno will fly over Jupiter's poles for the first time, taking pictures of the aurora (Northern and Southern lights) and measuring the magnetic field and particle fluxes in the radiation belts.  Juno's microwave radiometers will also map the synchrotron emission from the inside, allowing vast improvements to our computer models of the radiation belts.  NASA's Juno Mission is expecting GAVRT to supply the needed ground-based radio observations.