Jupiter and its Moons

Lab 4

Jupiter• 5th planet from the Sun• largest one in the solar system• if Jupiter were hollow, more than one thousand

Earths could fit inside• contains more matter than all of the other planets

combined• mass of 1.9 x 1027 kg• 28 known satellites, 4 of which (Callisto, Europa,

Ganymede and Io) were observed by Galileo in 1610• there is a ring system, but it is very faint• Jupiter radiates more energy into space than it

receives from the Sun. Its core is ~ 20,000˚ K.

Mythology associated

• Jupiter (Zeus) was the King of the Gods, the ruler of Olympus and the patron of the Roman state. Zeus was the son of Cronus (Saturn).

• Europa is named after the beautiful Phoenician princess who, according to Greek mythology, Zeus saw gathering flowers and immediately fell in love with. Zeus transformed himself into a white bull and carried Europa away to the island of Crete. He then revealed his true identity and Europa became the first queen of Crete. Zeus later re-created the shape of the white bull in the stars which is now known as the constellation Taurus.

Jupiter • composed of 90% hydrogen and 10% helium, with small

amounts of CH4, NH3, H2O vapor and other compounds• At great depths within Jupiter, the pressure is so great

that the hydrogen atoms are broken up, freeing the electrons so that the resulting atoms consist of bare protons. This produces a state in which the hydrogen becomes metallic

• dynamic weather systems illustrated by colorful latitudinal bands, atmospheric clouds and storms

• cloud patterns change within hours or days• The Great Red Spot is a complex storm moving in a

counter-clockwise direction. At the outer edge, material appears to rotate in four to six days; near the center, motions are small and nearly random in direction

Jupiter animation

• http://www.solarviews.com/raw/jup/vjupitr5.mpg

Internal Structure of Jupiter

• The outer layer is primarily composed of molecular hydrogen

• At greater depths the hydrogen starts resembling a liquid• At 10,000 kilometers below Jupiter's cloud top liquid

hydrogen reaches a pressure of 1,000,000 bar with a temperature of 6,000° K.

• At this state hydrogen changes into a phase of liquid metallic hydrogen. In this state, the hydrogen atoms break down yielding ionized protons and electrons similar to the Sun's interior.

• Below this is a layer dominated by ice where "ice" denotes a soupy liquid mixture of water, methane, and ammonia under high temperatures and pressures

• Finally at the center is a rocky or rocky-ice core of up to 10 Earth masses

The Galilean Moons

Ganymede

• largest moon of Jupiter and is the largest in our solar system with a diameter of 5,262 km (3,280 miles)

• composed of a rocky core with a water/ice mantle and a crust of rock and ice

• no known atmosphere, but presence of ozone means a thin tenuous oxygen atmosphere from charged particles disrupting surface ice

• http://www.solarviews.com/raw/jup/vgany2.mpg

Callisto

• 2nd largest moon of Jupiter, 3rd largest in the solar system, ~same size as Mercury

• orbits just beyond Jupiter's main radiation belt• Callisto is the most heavily cratered satellite in the solar

system• Its crust is very ancient and dates back 4x109 years• Callisto has the lowest density (1.86 gm/cm3) of the

Galilean• appears to be composed of a crust 200 km thick• Beneath the crust is a possible salty ocean ~10 km thick• Beneath the ocean, is an unusual interior composed of

compressed rock and ice with the percentage of rock increasing as depth increases

• Callisto, like Ganymede, has no known atmosphere

Callisto animation

• http://www.solarviews.com/raw/jup/vcallis1.mpg

Europa

• crust composed of water and ice• surface is among the brightest and smoothest in

the solar system• Lines and cracks wrap the exterior as if a child

had scribbled around it. • Europa may be internally active, and its crust

may have, or had in the past, liquid water which can harbor life

• http://www.solarviews.com/raw/jup/veuropa1.mpg

Io• most volcanic body known, with lava flows, lava

lakes, and giant calderas covering its sulfurous landscape

• billowing volcanic geysers spewing sulfurous plumes 500 km high

• Its mountains are much taller than those on Earth reaching heights of 16 km (52,000 feet)

• Io appears to be a rocky silicate rich body that has a dense Fe/FeS core that extends halfway to the surface with a partially melted silicate-rich mantle, and a thin rocky crust.

• http://www.solarviews.com/raw/jup/vio1.mpg

Internal Structure of Io

Very Exotic

• Io orbits very close to Jupiter's cloud tops, placing it within an intense radiation belt that bathes the satellite with energetic electrons, protons, and heavier ions

• As the Jovian magnetosphere rotates, it sweeps past Io and strips away ~1,000 kg (1 ton)/sec of volcanic gases

• This produces a neutral cloud of atoms orbiting with Io as well as a huge, doughnut shaped torus of ions that glow in the ultraviolet.

• Io acts as an electrical generator as it moves through Jupiter's magnetic field, developing 400,000 volts across its diameter and generating an electric current of 3x106

amperes that flows along the magnetic field to the planet's ionosphere

Using Kepler’s 3rd Law

• MJupiter = a3/P2

where M=mass of Jupiter in solar masses, a=radius of its moon’s orbit in AU, and P=period of its moon’s orbit in years

Converting to Keplerian Units

• If P=5 days, then 5/365 = 0.014 years

• If a = 3.5 JD, where JD is diameter of Jupiter,

then 3.5JD/(1050JD/AU)=0.0033AU