Download Jupiter (Jove) was the King of the Gods

Planet Jupiter
o Fifth planet from Sun.
o Largest planet.
o Twice as massive of all the other planets combined.
Earth Comparison
o Orbit:
5.20 AU
o Diameter:
11.2 Earths
o Mass:
318 Earths
History
o Jupiter (Jove) was the King of the Gods (Zeus).
o Fourth brightest object in the sky from Earth.
o Known as a “wandering star” since prehistoric times.
o Galileo (1610) used telescope to discover four moons: Io, Europa, Ganymede, Callisto
o Moons were first discovery of a center of motion not associated with Earth.
o Satellite motions and phases of Venus helped support Copernicus's heliocentric theory.
Visiting Spacecraft
o First visited by Pioneer 10 in 1973
o Pioneer 11
o Voyager 1
o Voyager 2
o Ulysses
o Galileo orbited Jupiter for eight years.
o JUNO, launched in 2011 and will arrive at Jupiter in 2016
Structure
o No solid surface, the gaseous materials simply get denser with depth.
o 90% hydrogen
o 10% helium
o Traces of methane, water, and ammonia.
o Similar to primordial Solar Nebula from which the solar system formed.
o Saturn has a similar composition.
o Uranus and Neptune have much less hydrogen and helium.
Interior – “Core”
o Knowledge of Jupiter’s interior is indirect.
o Galileo’s atmospheric probe only went to 150 km below the cloud tops.
o Jupiter probably has a core of rocky material amounting to 10 to 15 Earth-masses.
Interior – “Mantle"
o Liquid metallic hydrogen above the core makes up most of the planet.
o This exotic form of hydrogen is possible only at pressures exceeding 4 million Earth atmospheres.
o Liquid metallic hydrogen consists of ionized protons and electrons.
o It’s an electrical conductor and the source of Jupiter's magnetic field.
Outer “Layer” (atmosphere)
o The outermost layer is composed primarily of ordinary hydrogen and helium gas.
o Also includes:
o Water
o Carbon Dioxide
o Methane
o The atmosphere we see is just the very top of this deep layer.
Lack of “Layers”
o Experiments show that hydrogen does not change phase suddenly.
o Therefore there are no boundaries between the various interior layers.
Clouds
o Three layers of clouds consist of
o Ammonia Ice,
o Ammonium Hydrosulfide,
o and a mixture of ice and water.
Weather
o High velocity winds are confined in wide bands of latitude.
o Winds blow in opposite directions in adjacent bands.
o The Galilean probe indicates winds are more than 400 mph and extend down as far as the probe was
able to observe.
o Winds may extend down thousands of kilometers into the interior.
Band Characteristics
o Chemical and temperature differences between bands create colored effects.
o Light colored bands are called zones; the dark ones belts.
o Bands have been known for some time on Jupiter, but complex vortices in the boundary regions between
the bands were first seen by Voyager.
o Cloud colors correlate with altitude:
o Blue = lowest
o Brown = higher
o Whites = higher yet
o Red = highest
o Sometimes we see the lower layers through holes in the upper ones.
The Red Spot
o The Great Red Spot (GRS) has been seen for more than 300 years.
o Discovered by Cassini or Robert Hooke.
o The GRS is a 12,000 by 25,000 km oval, big enough to hold two Earths.
o Infrared observations and its rotation direction indicate that the GRS is a high-pressure region whose
cloud tops are significantly higher and colder than the surrounding regions.
o There are other spots such as Red Spot Junior.
o It is not known how such structures can persist for so long.
Radiation
o Jupiter radiates more energy into space than it receives from the Sun.
o The interior is hot: the core is about 20,000 K.
o Slow gravitational compression heats the planet.
o Interior heat causes convection deep within Jupiter's liquid layers and is probably responsible for the
complex motions we see in the cloud tops.
o Jupiter does NOT produce energy by nuclear fusion as in the Sun; it is much too small and hence its
interior is too cool to ignite nuclear reactions.
o If Jupiter were 80 times more massive, it would be a small star.
Magnetic Field
o Jupiter has a huge magnetic field, much stronger than Earth's.
o Its magnetosphere extends past the orbit of Saturn!
o Jupiter's moons therefore lie within it.
o Designers of the Voyager and Galileo spacecraft had to take in account the high levels of energetic
particles trapped by Jupiter's magnetic field.
o It would be immediately fatal to an unprotected human being.
Rings!
o Jupiter has rings like Saturn's, but much fainter and smaller.
o Unexpected and were only discovered 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.
o Unlike Saturn's, Jupiter's rings are dark.
o Composed of very small grains of rocky material.
o Particles don't stay there long due to atmospheric and magnetic drag.
o The Galileo spacecraft found clear evidence that the rings are continuously resupplied by dust formed by
micrometeor impacts on the four inner moons.
Comet Impact!
o In July 1994, Comet Shoemaker-Levy 9 collided with Jupiter with spectacular results.
o The effects were clearly visible even with small telescopes.
o The debris from the collision was visible for nearly a year afterward with HST.
The Moons
o Galilean moons are easily visible with binoculars; a few bands and the Great Red Spot can be seen with
a small telescope.
o Jupiter has 67 known satellites (as of 2013): the four large Galilean moons plus many more small ones
some of which have not yet been named:
o Jupiter's satellites are named for other figures in the life of Zeus (mostly his numerous lovers)
o Like the Earth-Moon system, Jupiter’s rotation is very gradually slowing down due to the tidal drag
produced by the Galilean satellites.
o Also, the same tidal forces are changing the orbits of the moons, very slowly forcing them farther from
Jupiter.
o Io, Europa and Ganymede are locked together in a 1:2:4 orbital resonance.
o In a few hundred million years, Callisto will be locked in too, orbiting at exactly twice the period of
Ganymede (eight times the period of Io).
o Jupiter's satellites are named for other figures in the life of Zeus (mostly his numerous lovers).