Space Station >> Physical Characteristics Of Jupiter

w Planetary composition

Jupiter is composed of a relatively small rocky core, surrounded by metallic hydrogen, surrounded by liquid hydrogen, which is surrounded by gaseous hydrogen. There is no clear boundary or surface between these different phases of hydrogen, the conditions blend smoothly from gas to liquid as one descends.

w Atmosphere

Jupiter's atmosphere is composed of ~81% hydrogen and ~18% helium by number of atoms. The atmosphere is ~75%/24% by mass; with ~1% of the mass accounted for by other substances - the interior contains denser materials such that the distribution is ~71%/24%/5%.The atmosphere contains trace amounts of methane, water vapor, ammonia, and "rock". There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine and sulfur. The outermost layer of the atmosphere contains crystals of frozen ammonia.

This atmospheric composition is very similar to that of the composition of the solar nebula. Saturn has a similar composition, but Uranus and Neptune have much less hydrogen and helium.Jupiter's upper atmosphere undergoes differential rotation, an effect first noticed by Giovanni-Cassini (1690).The rotation of Jupiter's polar atmosphere is ~5 minutes longer than that of the equatorial atmosphere. In addition, bands of clouds of different latitudes flow in opposing directions on the prevailing winds. The interactions of these circulation patterns cause storms and turbulence. Wind speeds of 600 km/h are not uncommon. A specific violent storm, about three times Earth's diameter, is known as the Great Red Spot, and has persisted through more than three centuries of human observation. The only spacecraft to have descended into Jupiter's atmosphere to take scientific measurements is the Galileo probe.

w Planetary Rings

Jupiter has a planetary ring system which is made of smoke-like dust particles knocked from its moons by meteor impacts. The main ring is made of dust from the satellites Adrastea and Metis. Two wide gossamer rings encircle the main ring, originating from Thebe and Amalthea. There is also an extremely tenuous and distant outer ring that circles Jupiter backwards. Its origin is uncertain, but this outer ring might be made of captured interplanetary dust.

w Magnetosphere

Jupiter has a very large and efficient magnetosphere. In fact, if you could see Jupiter's magnetic field from Earth, it would appear five times as large as the full moon in the sky despite being so much farther away. This magnetic field collects a large flux of particle radiation in Jupiter's radiation belts, as well as producing a dramatic gas torus and flux tube associated with Io. Jupiter's magnetosphere is the largest planetary structure in the solar system. The Pioneer probes confirmed that Jupiter's enormous magnetic field is 10 times stronger than Earth's and contains 20,000 times as much energy.

The sensitive instruments aboard was discovered that the Jovian magnetic field's "north" magnetic pole is at the planet’s geographic south pole, with the axis of the magnetic field tilted 11 degrees from the Jovian rotation axis and offset from the center of Jupiter in a manner similar to the axis of the Earth's field. The Pioneers measured the bow shock of the Jovian magnetosphere to the width of 26 million kms (16 million miles), with the magnetic tail extending beyond Saturn’s orbit.

The data showed that the magnetic field varies fatly in size on the sunward side of Jupiter because of pressure variations in the solar wind, an effect studied in further detail by the two Voyager spacecraft. It was also discovered that streams of high-energy atomic particles are ejected from the Jovian magnetosphere and travel as far as the orbit of the Earth. Energetic protons were found and measured in the Jovian radiation belt and electric currents were detected flowing between Jupiter and some of its moons, particularly Io.

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