What Lies Inside Jupiter?   
       
   July 29, 2011: Jupiter's swirling clouds can be seen through any department   
   store telescope. With no more effort than it takes to bend over an eyepiece,   
   you can witness storm systems bigger than Earth navigating ruddy belts that   
   stretch hundreds of thousands of kilometers around Jupiter's vast equator.   
   It's fascinating.   
   [...]   
   An artist's concept of Juno at Jupiter. [more]   
       
   It's also vexing. According to many researchers, the really interesting   
   things--from the roots of monster storms to stores of exotic matter--are   
   located at depth. The clouds themselves hide the greatest mysteries from view.   
       
   NASA's Juno probe, scheduled to launch on August 5th, could change all that.   
   The goal of the mission is to answer the question, What lies inside Jupiter?   
       
   "Our knowledge of Jupiter is truly skin deep," says Juno's principal   
   investigator, Scott Bolton of the SouthWest Research Institute in San Antonio,   
   TX. "Even the Galileo probe, which dived into the clouds in 1995, penetrated   
   no more than about 0.2% of Jupiter's radius."   
       
   There are many basic things researchers would like to know-like how far down   
   does the Great Red Spot go? How much water does Jupiter hold? And what is the   
   exotic material near the planet's core?   
       
   Juno will lift the veil without actually diving through the clouds. Bolton   
   explains how: "Swooping as low as 5000 km above the cloudtops, Juno will spend   
   a full year orbiting nearer to Jupiter than any previous spacecraft. The   
   probe's flight path will cover all latitudes and longitudes, allowing us to   
   fully map Jupiter's gravitational field and thus figure out how the interior   
   is layered."   
       
   Jupiter is made primarily of hydrogen, but only the outer layers may be in   
   gaseous form. Deep inside Jupiter, researchers believe, high temperatures and   
   crushing pressures transform the gas into an exotic form of matter known as   
   liquid metallic hydrogen--a liquid form of hydrogen akin to the slippery   
   mercury in an old-fashioned thermometer. Jupiter's powerful magnetic field   
   almost certainly springs from dynamo action inside this vast realm of   
   electrically conducting fluid.   
   [...]   
   Click to view a ScienceCast video entitled, "What Lies Inside Jupiter?" [video]   
       
   http://www.youtube.com/watch?v=QO27Wjl8e9c   
       
   "Juno's magnetometers will precisely map Jupiter's magnetic field," says   
   Bolton. "This will tell us a great deal about the planet's inner magnetic   
   dynamo [and the role liquid metallic hydrogen plays in it]."   
       
   Juno will also probe Jupiter's atmosphere using a set of microwave radiometers.   
       
   "Our sensors can measure the temperature and water content at depths where the   
   pressure is 50 times greater than what the Galileo probe experienced," says   
   Bolton.   
       
   Jupiter's water content is of particular interest. There are two leading   
   theories of Jupiter's origin: One holds that Jupiter formed more or less where   
   it is today, while the other suggests Jupiter formed at greater distances from   
   the sun, later migrating to its current location. (Imagine the havoc a giant   
   planet migrating through the solar system could cause.) The two theories   
   predict different amounts of water in Jupiter's interior, so Juno should be   
   able to distinguish between them-or rule out both.   
       
   Finally, Juno will get a grand view of the most powerful Northern Lights in   
   the Solar System.   
       
   "Juno's polar orbit is ideal for studying Jupiter's auroras," explains Bolton.   
   "They are really strong, and we don't fully understand how they are created."   
       
   Unlike Earth, which lights up in response to solar activity, Jupiter makes its   
   own auroras. The power source is the giant planet's own rotation. Although   
   Jupiter is ten times wider than Earth, it manages to spin around 2.5 times as   
   fast as our little planet. As any freshman engineering student knows, if you   
   spin a magnet-and Jupiter is a very big magnet-you've got an electric   
   generator. Induced electric fields accelerate particles toward Jupiter's poles   
   where the aurora action takes place. Remarkably, many of the particles that   
   rain down on Jupiter's poles appear to be ejecta from volcanoes on Io. How   
   this complicated system actually works is a puzzle.   
       
   It's a puzzle that members of the public will witness at close range thanks to   
   JunoCam-a public outreach instrument modeled on the descent camera for Mars   
   rover Curiosity. When Juno swoops low over the cloudtops, JunoCam will go to   
   work, snapping pictures better than the best Hubble images of Jupiter.   
       
   "JunoCam will show us what you would see if you were an astronaut orbiting   
   Jupiter," says Bolton. "I am looking forward to that."   
       
   Juno is slated to reach Jupiter in 2016.   
       
       
   Author: Dr. Tony Phillips | Credit: Science@NASA   
       
   More Information   
   Juno -- SWRI home page   
       
   Juno --- NASA home page   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.63   
    * Origin: NCS BBS (1:3828/7)