Encounter with Jupiter - Wavelength Virtual Astronomical Tours

Planet Profile - Jupiter

Mass: 1.90 x 10^27 kg
Diameter: 142,800 km
Mean density: 1314 kg/m^3
Escape velocity: 59500 m/sec
Average distance from Sun: 5.203 AU
Rotation period: 9.8 hours
Revolution period: 11.86 years
Obliquity: 3.08^°
Orbit inclination: 1.3^°
Orbit eccentricity: 0.048
Mean surface temperature: 120^° K
Visual geometricalbedo: 0.44
Atmospheric components: 90% hydrogen, 10% helium, .07% methane
Rings: Faint ring. Infrared spectra imply dark rock fragments.

Want to know your weight on Jupiter?

Jupiter was first visited by Pioneer 10 in 1973 and later by Pioneer 11, Voyager 1, Voyager 2 and Ulysses. The spacecraft Galileo is one of the latest to orbit around Jupiter and sending back data. Data from the Pioneer 10 and 11 spacecraft suggested that a ring system existed around Jupiter. This theory was confirmed when two of the Voyager 1 scientists insisted that after traveling 1 billion km it was at least worth a quick look to see if any rings might be present. They have since been imaged in the infra-red from ground-based telescopes and by Galileo.

Jupiter has rings like Saturn's, but much fainter and smaller, the main ring is 7000 km or 4350 miles wide. Unlike Saturn's, Jupiter's rings are dark, with an albedo of about .05. They're probably composed of very small grains of rocky material. Unlike Saturn's rings, they seem to contain no ice. Particles in Jupiter's rings probably don't stay there for long because of atmospheric and magnetic drag. The Galileo spacecraft found clear evidence that the rings are continuously resupplied by dust formed in micrometeor impacts on the four inner moons, which are very energetic because of Jupiter's large gravitational field. The inner halo ring is broadened by interactions with Jupiter's magnetic field.

The colorful, wavy cloud pattern to the left of the Red Spot is a region of extraordinarily complex wave motion. This dramatic view of the Great Red Spot and its surroundings was taken February 25, 1979, when Voyager 1 was 9.2 million km or 5.7 million miles from Jupiter. An atmospheric system larger than Earth and more than 300 years old, the Great Red Spot remains a mystery. Swirling, storm-like features possibly associated with wind shear can be seen both to the left and above the Red Spot.

This mosaic of the Great Red Spot was taken by the Voyager 2 spacecraft. It shows that the region changed significantly since the Voyager 1 encounter four months earlier. Around the northern boundary a white cloud is seen, which extends east of the region. The presence of this cloud prevents small cloud vertices from circling the spot in the manner seen in the Voyager 1 encounter.

In July 1994, Comet Shoemaker-Levy 9 collided with Jupiter with spectacular results (left). The effects were clearly visible even with amateur telescopes. The debris from the collision was visible for nearly a year afterward with HST.

The King of The Solar System

Jupiter was the King of the Gods, the ruler of Olympus and the patron of the Roman state. Jupiter is the fifth planet from the Sun and by far the largest. Jupiter is more than twice as massive as all the other planets combined 318 times Earth. Jupiter's diameter is 11 times Earth's diameter and 20% larger than Saturn's.

Jupiter is the fourth brightest object in the sky after the Sun, the Moon and Venus; but there are times when Mars is also brighter. Galileo discoved, four of Jupiter's larger moons in 1610, Io, Europa, Ganymede and Callisto. These four moons are now known as the Galilean moons. Their discovery was the first example of bodies in motion that were not centered around the Earth. It was a major piece of evidence supporting Copernicus's heliocentric theory of the motions of the planets. Galileo's outspoken support of Copernican theory, and his satire of the Church officials put him at odds with the Inquisition.

Jupiter is a "gas giant"; all gas giants are similar to Jupiter and Saturn in composition.The gas planets do not have solid surfaces, their gaseous material simply gets denser with depth. What we see when looking at these planets is the tops of clouds high in their atmospheres slightly above the 1 atmosphere level. Gas giants are also very much larger than terrestrial planets.

An Inside Look at Jupiter

Jupiter is about 90% hydrogen and 10% helium by numbers of atoms, 75/25% by mass with traces of methane, water, ammonia and "rock". This is very close to the composition of the primordial Solar Nebula from which the entire solar system was formed. Saturn has a similar composition, but Uranus and Neptune have much less hydrogen and helium.

Our knowledge of the interior of Jupiter and the other gas planets is very indirect and is likely to remain so for some time. Jupiter probably has a core of rocky material amounting to something like 10 to 15 times the mass of the Earth. Above the core lies the main bulk of the planet in the form of liquid metallic hydrogen.

This exotic form of the most common of elements is possible only at pressures exceeding 4 million bars, as is the case in the interior of Jupiter and Saturn. Liquid metallic hydrogen consists of ionized protons and electrons similar to the interior of the Sun but at a far lower temperature. At the temperature and pressure of Jupiter's interior hydrogen is a liquid, not a gas. It is an electrical conductor and the source of Jupiter's magnetic field. This layer probably also contains some helium and traces of various "ices".

Jupiter And Its Satellites

Ira Boucher - Ira Designs