Rex Feldmann, age 16, of Butte, Mont., for his question:
WHAT IS JUPITER'S RADIO RADIATION
Jupiter is the largest planet in our solar system. It is more than 11 times the diameter of the Earth. Unlike the other planets, Jupiter sends out rather strong radio radiation.
The radiation of Jupiter is received in two forms: as bursts of radio energy and as continuous radio energy. It can be received on this planet by radio telescopes.
American astronomers Bernard Burke and Kenneth Franklin were the first to hear the bursts of radio energy. They made their discovery in 1955.
Since the mid 1950s, other astronomers have found that these bursts of radio radiation often occur at the same point during Jupiter's rotation on its axis. The bursts do not occur during each rotation, but they do follow a somewhat regular pattern.
Most astronomers think that Jupiter's radio radiation comes from high energy particles that form radiation belts around the planet. The particles, which are given off by the sun, are trapped by Jupiter's magnetic field. The bursts of radio radiation may result from the trapped particles hitting the top of Jupiter's atmosphere.
Jupiter has a greater mass than any other planet 318 times greater than the Earth. The force of gravity in Jupiter is also greater. A 100 pound person on the Earth would weigh about 264 pounds on Jupiter.
Jupiter has a large mass, but it has a low density. It is slightly more dense than water and about one fourth as dense as the Earth. Saturn is the only planet that has a lower density than Jupiter.
Most astronomers believe that Jupiter is a large ball of hot liquid that has no solid surface. However, the planet may have a small solid core of rocky material. The surface cannot be seen because of the layers of dense clouds that surround the planet.
When viewed through a telescope, a series of belts and zones can be seen on Jupiter's clouds.
The belts and zones on Jupiter's surface may be caused by various gases in the clouds. The zones are light colored areas between the belts, while the belts are dark lines that circle the planet parallel to its equator. The widths and positions of the belts change slowly through the years.
Jupiter has at least 63 satellites more than any other planet. The four largest satellites appear to consist chiefly of rocky material and ice. They have diameters greater than 1,900 miles.
The satellites of Jupiter are called Galilean satellites because the Italian astronomer Galileo discovered them in 1610.
The diameter of the largest satellite, called Ganymede, is about 3,480 miles, or 380 miles greater than the diameter of the planet Mercury.
Jupiter's nine smaller satellites have diameters ranging from about 5 to 100 miles. They were discovered by early astronomers using telescopes and recent discoveries by the NASA Voyager and Cassini spacecraft.