Jupiter. Largest and most massive planet in the solar system Contains almost ¾ of all planetary...
-
Upload
richard-golden -
Category
Documents
-
view
224 -
download
2
Transcript of Jupiter. Largest and most massive planet in the solar system Contains almost ¾ of all planetary...
Jupiter
JupiterLargest and most massive planet in the solar systemContains almost ¾ of all planetary matter in the solar system.
Explored in detail by several space probes:
Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Galileo
Most striking features visible from Earth: Multi-
colored cloud belts
Visual image
Infrared false-color image
Exploration of Jupiter
Previous Missions
Pioneer 10 & 11Voyager 1 & 2
Latest Jupiter Mission
Galileo (1995 - 2003)
Galileo Probe
What did it tell us?
What did we expect?
Jupiter’s Rotation
Jupiter is the most rapidly rotating planet in the solar system
Rotation period slightly less than 10 hr.
Centrifugal forces stretch Jupiter into a markedly oblate shape.
Jupiter’s Atmosphere
Jupiter’s liquid hydrogen ocean has no surface:
Gradual transition from gaseous to liquid phases.
Only very thin atmosphere above cloud
layers;
transition to liquid hydrogen zone ~ 1000 km below
clouds.
Jupiter’s Cloud layers• Haze (at the top)• Ammonia• Ammonium Hydrosulfide• Water (lowest observed layer)
What did the Probe find?
At depth of 1 bar (Earth Sea level):
T = 130 K (-225 F), P=1 bar
Survived to a depth of 150 km:
T = 425 K (305 F), P=22 bars
Hotter and denser than expected
Ammonia and water layers were not detected
Wind velocities much greater (435 mph)
Chemically like Sun in terms of H, He, but a bit off in other elements
Jupiter’s AtmosphereThree layers of clouds:
1. Ammonia
(NH3) crystals
2. Ammonia hydrosulfide
(NH4SH)
3. Water crystals
Heating mostly from latent, internal heat
Observations of Jupiter from the Earth reveal clouds and atmospheric structures
Belts
Zones
The Cloud Belts of JupiterDark belts and bright zones.
Zones higher and cooler than belts; high-pressure regions of
rising gas.
The Cloud Belts on JupiterJust like on Earth, high-and low-pressure
zones are bounded by high-pressure winds.
Jupiter’s Cloud belt structure has remained unchanged since humans began mapping them.
Clouds, clouds, cloudsRotation rate is about 10 hours
Differential Rotation (different parts rotate at different rates)
Produces turbulence, and storms
© Calvin Hamilton
The Great Red Spot
8-year sequence of images of the Great Red Spot on Jupiter
Has been visible for over 400 years
Giant storm system similar to Hurricanes on Earth: Wind speeds of 430 km/h (= 270 miles/h)Changes appearance gradually over time
The Great Red Spot
A storm that has been going on for nearly 400 years
2-3 x size of the Earth
The History of Jupiter Formed from cold gas in the outer solar nebula, where ices were able to condense.
Rapid growth
Soon able to trap gas directly through gravity
Heavy materials sink to the center
In the interior, hydrogen becomes metallic (very good electrical conductor)
Rapid rotation → strong magnetic field
Rapid rotation and large size → belt-zone cloud pattern
Dust from meteorite impacts onto inner moons trapped to form ring
Jupiter’s Magnetic FieldMagnetic field at least 10 times stronger than Earth’s magnetic field.
Magnetosphere over 100 times larger than Earth’s magnetosphere
Aurorae on JupiterJust like on Earth, Jupiter’s magnetosphere produces aurorae concentrated in rings around the magnetic poles. ~ 1000 times more powerful than aurorae on Earth.
Particles producing the aurorae originate mostly from moon Io
Aurora requires a magnetic field
What’s Jupiter’s magnetic field like?
How is it produced?
Rock and Metal
Liquid MetallicHydrogen
Liquid Hydrogen
Molecular Hydrogen
Jupiter’s Ring System
Jupiter’s RingNot only Saturn, but all four gas giants have rings.
Jupiter’s ring: dark and reddish;
only discovered by Voyager 1
spacecraft.
Galileo spacecraft image of Jupiter’s ring, illuminated from behind
Composed of microscopic particles of
rocky material
Location: Inside Roche limit, where larger bodies (moons) would be destroyed by tidal forces.
Satellites of Jupiter
Currently 60+ known satellites - most
Most small asteroid-like, only a few km in size
4 largest satellites are the Galilean Satellites
Io, Europa, Ganymede, Callisto
The Galilean Satellites
Io - The Volcanic World
Io: Bursting EnergyMost active of all Galilean moons; no impact craters visible at all.
Over 100 active volcanoes!
Interior is mostly rock.
Activity powered by tidal interactions with Jupiter.
Surface features have changed since the Voyager spacecraft visited (1979) and the Galileo spacecraft’s observations (late 1990’s)
Continual volcanic eruptions
Why?
Io has the highest density
Io has the fewest craters - youngest surface
Io is closest to Jupiter
And on the other side are the other 3 large satellites
Io is a victim of a tug of war (tidal heating) due to Jupiter and the other moons!
Jupiter’s Influence on its MoonsPresence of Jupiter has at least
two effects on geology of its moons:
1. Tidal effects: possible source of heat for interior of Ganymede
2. Focusing of meteoroids, exposing nearby satellites to more impacts than those further out.
Interactions with Jupiter’s MagnetosphereIo’s volcanoes blow out sulfur-rich gases
→ tenuous atmosphere, but gases can not be retained by Io’s gravity
→ gases escape from Io and form an ion torus in Jupiter’s magnetosphere.
→ Aurorae on Jupiter are fueled by particles from Io
Europa - The Ice World
Europa: A Hidden Ocean
Close to Jupiter → should be hit by many meteoroid impacts; but few craters visible.
→ Active surface; impact craters rapidly erased.
The Surface of Europa
Cracked surface and high albedo (reflectivity) provide further evidence for geological activity.
Ice features that are slowly changing
Very few craters
Lower density than Io
Slightly older surface
The Interior of EuropaEuropa is too small to retain its internal heat → Heating mostly from tidal interaction with Jupiter.
Europa has a liquid water ocean ~ 15 km below the icy surface.
Ganymede - The Largest Moon
Ganymede: A Hidden PastLargest of the 4 Galilean moons. Rocky core
Ice-rich mantle Crust of ice
1/3 of surface old, dark, cratered; rest: bright, young, grooved terrain
Bright terrain probably formed through flooding when surface broke
Light and Dark Terrain indicates some resurfacing
Lower Density
More craters, Less resurfacing
Older surface than Europa
Callisto - The Cratered Moon
Callisto: The Ancient FaceTidally locked to Jupiter, like all of Jupiter’s moons.
Composition: mixture of ice and rocks
Dark surface, heavily pocked with craters.
No metallic core: Callisto never differentiated to form core and mantle.→ No magnetic field.
Layer of liquid water, ~ 10 km thick, ~ 100 km below surface, probably heated by radioactive decay.
Valhalla Impact Basin - rings extend out 1500 km
Lowest Density
Most craters
Very little resurfacing
Oldest surface