ch 13-2 uranus and neptune pt 2

How do the magnetic fields of Uranus and Neptune differ from Earth's?

• Their magnetic fields are tilted at large angles relative to their rotation axes.

Are the magnetic fields of Uranus and Neptune dipolar?

• No. Their magnetic fields are complex and not simple dipoles.

• chaotic nature makes them hard to understand

What does "not dipolar" mean?

• The magnetic field is not shaped like a simple north-south bar magnet.

Do Uranus and Neptune have substantial magnetic fields?

• Yes, both planets have strong magnetic fields despite their unusual geometry.

Why are the magnetic fields of Uranus and Neptune unusual?

• They are highly tilted, off-center, and not simple dipole magnetic fields.

What produces the magnetic fields of Uranus and Neptune?

• A thin layer of electrically conductive fluid rich in ions beneath the atmosphere.

• stratified layers

Why can the fluid inside Uranus and Neptune conduct electricity?

• Extreme pressures create ion-rich materials that conduct electricity.

What materials are found in the conductive layers of Uranus and Neptune?

• Water, ammonia, and methane under extreme pressure.

what does thin watery layer porduce?

• magnetism

how many moons does Uranus have?

• 28 moons

  • 5 major

  • spherical

  • equal part ice and rock

5 major moons of Uranus

• Miranda, Ariel, Umbriel, Titania, and Oberon

Uranus moons are similar to Saturn’s medium sized moons, except?

• that all are much less reflective

which is the darkest moons of Uranus?

• Umbriel

what are the outermost moons of Uranus?

• Titania and Oberon

  • heavily cratered and little indication of geological activity

  • less reflective

Uranus moon: Miranda

• most unusual moon of Uranus

• smallest and inner most

• varied landscaped surface (complex geological history)

• mix of heavy cratered old regions and younger

what is the origin of Mirandas cracks and grooves?

• unknown

3 large race like structures found on Miranda

• corona

• 20 km deep

• upwelling of ice

massive fault canyons on Miranda

• intense geological activity stretching of crust

How many moons does Neptune have?

• 16 moons

  • only 2 can be seen from Earth

which of Neptune’s moon can be seen from Earth?

• Triton and Nereid

what kind of orbit is Triton in?

• retrograde orbit

  • opposite of planets rotation

what kind of orbit is Nereid’s in?

• highly eccentric

  • elongated and non circular

what is the result of the tidal bulge on Neptune?

• tends to make moon spiral toward planet rather than away

  • doomed to collide with planet

Which moon of Neptune is thought to be a captured Kuiper Belt Object?

• Triton.

What evidence suggests Triton was captured by Neptune?

• Its retrograde, highly inclined orbit and composition similar to Pluto.

Triton’s surface?

• has few craters, indicating an active surface

  • young

what has been observed on the surface of Triton?

• Nitrogen geysers, contributing to the surface features

  • erupt Nitrogen gas

Triton cryovolcanism

• active ice volcanoes

• erupt methane ice

• plumes rises 8km from internal heat of nitrogen ice beneath surface

Uranus and Neptune’s rings

• faint detected via stellar occultation

  • observed planet passing in front of star causing it to flicker

the rings of Uranus

• 13 known distinct rings

  • divide to inner narrow rings and outer more colorful dusting rings

what are Uranus rings composed of?

• water like compounds, young, replenished by collisions from moons

What are shepherd moons?

• small moons whose gravity helps confine and maintain planetary rings.

How do shepherd moons affect Uranus's Epsilon Ring?

• they prevent the ring particles from spreading out and keep the ring narrow.

What does it mean for a ring to diffuse?

• The ring particles spread out over a larger area.

Which moons shepherd Uranus's Epsilon Ring?

• Cordelia orbits inside the ring, and Ophelia orbits outside the ring.

how many rings does Neptune have?

• 5 rings

  • 3 narrow and 2 wide (broad and diffuse)

composition of Neptune’s rings

• should spread out and not clump

• believe moon nearby ring stabilizes them

• dark, dust, young, short lives

Uranus and Neptune heat emission

• urnaus has no excess heat emission, but neptune does