Universe 1

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Uranus & Neptune

The water planets

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Uranian planets

The Uranian Planets

4x Earth diameter Bluish green H atmospheres Methane gives blue tint Uranus 3rd largest in size Neptune 3rd largest in mass Watery interiors

Watery "slush"

Rocky core

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Uranian planets

Uranus discovery

William Herschel, 1781 First planet discovered

telescopically 20 AU from Sun – doubled

size of Solar System

Saturn

Uranus

Universe 2

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Uranian planets

UranusPre-Voyager discoveries

Orbital period 84 years 5 medium-sized moons Axis tilted 90º Rings detected 1977 by stellar

occultation

Gerard Kuiper

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Uranian planets

Uranus seasons

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Uranian planets

UranusVoyager 2 encounter

January 1986 Solstice Bull’s eye

Universe 3

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Uranian planets

UranusAtmosphere

Nearly featureless fuzzball. A few clouds of methane ice East-west winds Temperature the same on day

side as night side.

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Uranian planets

UranusOther Voyager 2 results

10 new small inner moons 2 innermost: shepherd moons

Close-ups of rings Bizarre magnetic field

tilted 60º offset 1/3 toward surface Rotation period: 17 hr

Shepherd moons

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Uranian planets

Uranus rings

Universe 4

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Uranian planets

Discovery of Neptune1846

Uranus deviates Unseen gravitational source Jean Joseph LeVerrier John Couch Adams Johann Gottfried Galle, Berlin

Observatory

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Uranian planets

Neptune Pre-Voyager discoveries

Moons Triton (retrograde) Nereid (eccentric)

Rotation: 16 hours “Ring arcs”

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Uranian planets

NeptuneVoyager 2 encounter

August 1989 Close pass over north pole Triton last encounter

Universe 5

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Uranian planets

Voyager at NeptuneAtmosphere

Great Dark Spot Methane ice clouds Fastest winds: >1200 km/hr Mysterious underlying cloud deck

Great Dark Spot

Lesser Dark Spot

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Uranian planets

The Great Dark Spot

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Uranian planets

Cloud Shadows

Universe 6

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Uranian planets

Voyager at NeptuneOther results

6 new moons Proteus 2nd largest Innermost associated

with rings

Proteus

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Uranian planets

Neptune Rings

Rings 2 main rings Thin sheet mysterious thick

spots

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Uranian planets

Magnetic Fields

Neptune's magnetic fieldis tilted like Uranus's.