Lecture 20: Jupiter

"By Jove, I think she's got it!"

My Fair Lady



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  • Date: November 18, 1994
    Reading Assignment: pp. 260-281

    Description : overview of Jupiter and it's moons

    Objectives

  • Be able to describe the composition of Jupiter's atmosphere.
  • Be able to describe the magnetosphere of Jupiter.
  • Be able to describe the differences between the inner and outer Galilean Moons.
  • Be able to discuss the basic characteristics of Jupiter, such as mass, rotation, composition, and orbital characteristics.
  • Understand that the moons of Jupiter probably did not all form in the same way.
  • Be able to describe the temperature of Jupiter and why this temperature is a bit unexpected.
  • Be able to explain differential rotation.

  • Lecture Outline

    Slide # 1: Lecture 12- Jupiter

    Slide # 2: Jupiter
  • orbit and rotation
  • composition and internal structure
  • surface features and history
  • atmosphere
  • magnetosphere
  • moons
  • Slide # 3: Planetary Structure
  • core
  • mantle
  • crust
  • hydrosphere
  • atmosphere
  • magnetosphere
  • Slide # 4: Jovian Planet Sizes Slide # 5: Planetary Orbits
  • outer solar system
  • Slide # 6: Jupiter- Revolution
  • semimajor axis = 5.20 AU
  • slightly elliptical orbit
  • orbital period = 11.9 Earth Years
  • Slide # 7: Moons
  • Mercury, Venus - none
  • Earth - 1
  • Mars - 2
  • Jupiter - 16
  • Saturn - 18
  • Uranus - 15
  • Neptune - 8
  • Pluto - 1
  • Slide # 8: Planetary Masses
  • Mercury = 1/20
  • Venus = 4/5
  • Earth = 1
  • Mars = 1/9
  • Jupiter = 318
  • Saturn = 95
  • Uranus = 15
  • Neptune = 17
  • Pluto = 0.002
  • Slide # 9: JupiterÕs Rotation
  • rotation is usually measured by observing surface features
  • Jupiter has no surface
  • Slide # 10: Measurements of JupiterÕs Rotation
  • observing cloud
  • Doppler measurements
  • magnetic fields
  • Slide # 11: JupiterÕs Rotation
  • 9h 50m at the Equator
  • 9h 56m near the poles
  • differential rotation
  • clouds are rotating at different speeds
  • Slide # 12: Differential Rotation
  • Jupiter is NOT a solid planet
  • Slide # 13: Magnetic Field Measurements
  • JupiterÕs core seems to be rotating every 9h 56m
  • detected by analysing radio signals
  • Slide # 14: JupiterÕs Rotation
  • fastest rotation of any planet in the solar system
  • causes Jupiter to have an equatorial bulge
  • Slide # 15: JupiterÕs Shape
  • oblateness of 0.065
  • Slide # 16: Atmospheric Composition of Jupiter
  • hydrogen (86.1%)
  • helium (13.8%)
  • traces of other gases (<1%)
  • methane
  • ammonia
  • water vapor
  • Slide # 17: Views of Jupiter
  • ground-based telescope
  • Slide # 18: Views of Jupiter
  • Voyager 1 Spacecraft
  • Slide # 19: Cloud Layers of Jupiter
  • structure of the atmosphere
  • Slide # 20: Why the Pretty Colors?
  • complex chemistry in the atmosphere
  • difficult to understand all the chemistry without more data
  • Slide # 21: Atmospheric Zones
  • bright zones
  • rising regions
  • dark belts
  • sinking regions
  • parts of the convection cycle
  • caused by circulation of the atmosphere
  • Slide # 22: Zones and Belts
  • side view
  • Slide # 23: The Red Spot
  • ancient hurricane on Jupiter
  • Slide # 24: Weather on Jupiter
  • the Great Red Spot
  • 300 year old hurricane
  • 25,000 km in diameter
  • many turbulent oval features
  • lightning detected
  • aurora detected
  • Slide # 25: Shoemaker- Levy 9
  • optical view of Jupiter
  • Slide # 26: Shoemaker- Levy 9
  • infrared view of Jupiter
  • Slide # 27: Shoemaker-Levy 9
  • donÕt let this happen to your planet
  • Slide # 28: Atmospheres
  • molecular speed and escape velocity
  • Slide # 29: Origin of the Atmospheres
  • primary atmosphere- Hydrogen and Helium
  • gases common in the solar system
  • nearly identical to SunÕs composition
  • too cold and too much gravity for any gases to escape
  • Slide # 30: Surface Heating of Planets
  • Most planets are warmed mainly by the SunÕs energy
  • sunlight strikes planetÕs surface and is absorbed
  • planet warms
  • planet radiates as a Black-Body
  • Slide # 31: Temperature of Jupiter
  • expected temperature should be 105K
  • measured temperature is 125K
  • 20K difference in temperature
  • Slide # 32: Energy Radiated
  • StephanÕs Law
  • energy proportional to temperature to fourth power
  • (125/105)4 = (actual energy / solar energy)4
  • Jupiter radiates twice as much energy as it receives from the Sun
  • Slide # 33: JupiterÕs Heat
  • NOT the Greenhouse effect
  • More energy is leaving Jupiter than arrives
  • Jupiter has an internal heat source
  • Slide # 34: JupiterÕs Heat
  • energy cannot be nuclear fusion or fission
  • not enough compression for fusion
  • not enough radioactive elements for fission
  • must be energy from the gravitational from the planetÕs formation
  • Slide # 35: Internal Structure
  • no seismic information is possible
  • we must rely on computer models
  • some tests possible through observations
  • Slide # 36: Internal Structure
  • big ball of mostly hydrogen
  • Slide # 37: Exploration of Jupiter
  • Pioneer 10 (December 1973)
  • Pioneer 11 (December 1974)
  • Voyager 1 (March 1977)
  • Voyager 2 (July 1977)
  • Slide # 38: Magnetic Fields
  • two conditions needed to form magnetic fields
  • liquid metal core
  • rapid rotation
  • Jupiter has rapid rotation and a large metallic hydrogen core
  • Slide # 39: Magnetic Field from Jupiter
  • Jupiter has a GIANT magnetosphere
  • Slide # 40: Magnetosphere
  • the magnetosphere extends over 5 AUÕs
  • 20,000 times stronger than EarthÕs magnetic field
  • radiation belts thousands of times stronger than EarthÕs
  • Slide # 41: Moons of Jupiter
  • at least 16 moons
  • four major groups of moons
  • inner satellites
  • Galilean satellites
  • prograde outer satellites
  • retrograde outer satellites
  • Slide # 42: Inner Moons
  • seem to be similar to large asteroids
  • probably big rocks
  • Slide # 43: Inner Moons
  • orbital sizes 1.79 to 3.11 planetary radii
  • diameters 20 to 200 km
  • low reflectivity
  • Albedo 0.05
  • circular orbits
  • Example: Amalthea
  • Slide # 44: Amalthea
  • potatos in space
  • Slide # 45: Galilean Moons
  • discovered by Galileo
  • orbital sizes 5.91 to 26.4 planetary radii
  • diameters 3140 to 5260 km
  • high reflectivity
  • Albedo 0.2 to 0.6
  • circular orbits
  • Io, Europa, Ganymede, Callistro
  • Slide # 46: Galilean Moons
  • Io and Europa
  • rocky composition- density 3.6 and 3.0 gm/cm3
  • inner Galilean moons
  • Callisto and Ganymede
  • lighter materials- lots of icy materials
  • lower density - 1.9 gm/cm3
  • outer Galilean moons
  • All these moons have
  • circular orbits
  • near the equatorial plain of Jupiter
  • Slide # 47: Prograde Moons
  • orbital sizes 155 to 164 planetary radii
  • diameters 239 to 260 km
  • low reflectivity
  • Albedo 0.03 to 0.05
  • eccentric (elliptical) orbits
  • Example: Leda
  • Slide # 48: Retrograde Moons
  • orbital sizes 297 to 332 planetary radii
  • diameters 30 to 70 km (?)
  • reflectivity- unknown
  • orbits eccentric and RETROGRADE
  • Example: Pasiphae
  • Slide # 49: Outer MoonÕs Origin
  • retrograde outer moons were almost certainly captured
  • probably originally ONE bigger moon which broke apart
  • prograde outer moons were probably captured
  • probably orginally ONE bigger moon which broke apart
  • Slide # 50: Geology of the Big Moons
  • the Galilean moons are a great chance to look at other ŌTerrestrial PlanetsĶ
  • Slide # 51: Io
  • moon of pizza
  • Slide # 52: Io
  • ACTIVE volcanos
  • eruptions detected by Voyager 1 and 2
  • heating and volcanos caused by tidal forces from Jupiter
  • Slide # 53: Volcanics on Io
  • Voyager detected volcanic plume
  • Slide # 54: Volcanos on Io
  • tidal forces from Jupiter squeeze Io
  • Slide # 55: Europa
  • few craters
  • frozen WATER ICE
  • many crossed lines
  • white color
  • possible geyser eruptions
  • possible water ocean under the ice
  • Slide # 56: Europa
  • broken cue-ball in space
  • Slide # 57: Ganymede
  • similar to the structure of EarthÕs Moon
  • water on Ganymede replaces lava on the Moon
  • frozen maria cover much of the landscape
  • Grooved terrain and ridges may come from ancient plate tectonics
  • Slide # 58: Ganymede
  • icy craters and grooves
  • Slide # 59: Callisto
  • similar to Ganymede
  • more craters and fewer faults
  • evidence of a big impact in the Valhalla basin
  • no evidence of plate tectonic activity
  • froze before plates could form
  • Slide # 60: Callisto
  • icy craters and a big impact
  • Slide # 61: Galilean Moons
  • moons and more moons
  • Slide # 62: JupiterÕs Ring
  • Jupiter has a faint ring
  • similar to the ring of Saturn, but much much less spectular
  • Slide # 63: Views of Jupiter
  • ring around the planet
  • Slide # 64: Jupiter
  • orbit and rotation
  • composition and internal structure
  • surface features and history
  • atmosphere
  • magnetosphere
  • moons