Jupiter & Saturn
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Transcript of Jupiter & Saturn
Jupiter & SaturnLecture 22
Jupiter & Saturn at glance
As seen from the Earth
As seen from the space
Differential RotationDifferential rotation typifies Jupiter and Saturn: Particles at different locations in the fluid take different lengths of time to complete one rotation.
Solid rotation typifies the terrestrial planets: Every part of the object takes exactly the same time to complete one rotation.
(a) Pioneer 11, December 1974 (c) HST, February 1995(b) Voyager 2, July 1979
White ovals
The Great Red Spot lies within a white zone.
A dark belt has encroached on the Great Red Spot.
The Great Red Spot again lies within a white zone.
20,000 km Earth’s diameter
Turbulence downwind of the Great Red Spot
Winds on the north side of the Great Red Spot flow westward.
Winds on the south side of the Great Red Spot flow eastward.
Winds within the Great Red Spot circulate counterclockwise.
Great Red Spot of Jupiter
Regularities in Jupiter’s Atmosphere
http://bcs.whfreeman.com/webpub/astronomy/Videos/MotionsofJupitersAtmosphere_clearSkin_3/MotionsofJupitersAtmosphere.html
Great Red Spot is a strong massive storm
Atmospheres
Saturn has lower atmospheric temperatures than Jupiter.
Saturn has weaker surface gravity than Jupiter, so its cloud layers are more spread out.
Internal Structure
Jupiter’s Magnetic Field
Saturn’s Magnetic Field
Saturn’s Ring
Gravitational effects carve gaps in the rings and focus ring particles into narrow ringlets.
Shaping a ringhttp://bcs.whfreeman.com/webpub/astronomy/Videos/ShapingSaturnsFRing_clearSkin_3/ShapingSaturnsFRing.html
Changing Appearance of Saturn’s Ring
Jupiter has a ring too! Saturn’s ring = icy fragment Jupiter’s ring = rocky particles
Voyager 2 first took an image of “spokes” in the Saturn’s ring. This dark radial features rotate with the Saturn. It is thought to be related to the magnetic field of the Saturn
Cannot be a shape due to the gravitational force alone. Why?
Spokes in the Saturn’s Ring
Roche Limit
Within ~2.5 times the radius of a planet, it’s dangerous!
In summary…
Important ConceptsComposition & StructureAtmosphere and Magnetic FieldsOrigin of rings
Important TermsDifferential RotationRoche limit
Chapter/sections covered in this lecture : Chapter 12