Lecture 8: Giant Planets Flashcards
1
Q
Giant Planets
A
- Rapidly rotating
- Large gravitationally bound balls of fluid
- Rotation flattens spheres into ellipsoid’s
- all have different interiors
- 3/4 have internal heat sources
- all 4 have strong magnetic fields and huge magnetospheres
- Auroral zones near magnetic poles
- All atmospheres are approximately the same structure, with differences in pressure, composition, and minimum temperature
2
Q
Jupiter
A
- Jupiter’s interior is differentiated (layers of hydrogen then the core)
- Atmosphere is result of heat, convection, and rotation
- Strong magnetic field
- No true surface
- Very oblate and fast rotation
- Hotter than expected but no greenhouse effect, planet is contracting
- mostly hydrogen and helium interior with metallic Hydrogen and rocky core
3
Q
Saturn
A
- Saturn is the most oblate giant planet
- Layered banded atmosphere
- strong magnetic field
- rocky core
- Largest rings in solar system
- North pole hexagonal cloud pattern
4
Q
Uranus
A
- Accidentally discovered in 1781 by telescope
- faint features, blue atmosphere (methane absorbs red wavelengths and reflects blue)
- hydrogen helium, methane clouds
- strong magnetic field
- no metallic hydrogen, but rocky core
- axis tilt 98º, very strong seasonal effect
5
Q
Neptune
A
- position predicted from observations of Uranus
- discovered in 1846
- unknown molecule makes colour deeper blue than Uranus
- More cloud features
- Large storm features like Jupiter (change a lot)
6
Q
Jupiter Giant Satellites
A
- Some large, many small
- some geologically active, now and in the past
- some formed with the planet, some captured
- Overall, surface age increases and mean density decreases with distance from Jupiter
- Orbital resonance brings Io, Europa, and Ganymede to the same position every 7 days
7
Q
Io
A
- Io is geologically active (most in solar system)
- covered in orange sulphur compounds
- strongly tied to Jupiter’s magnetic field
- tidal interaction and eccentric orbit heat interior
- Charged particles escaping Io interact with Jupiter’s magnetosphere
8
Q
Europa
A
- Europa has a smooth surface with few craters
- water ice, possibly over liquid water
- rocky interior and metallic core
- layer of liquid water or warm convecting ice
9
Q
Ganymede
A
- Ganymede is the largest moon in the solar system
- water ice over much of surface
- smooth surface and cracked terrain the result of tidal heating and icy composition
10
Q
Callisto
A
- Callisto is heavily cratered
- concentric circular ridges are signs of large impact
- most aged surface of the big four Galilean satellites
11
Q
Saturn’s Moons
A
- Many moons, probably many still to be discovered
- Innermost moons tidally locked to planet
- Moons interact with rings
- Varied, enigmatic
12
Q
Titan
A
- Largest of Saturn’s Moons
- dense, thick nitrogen atmosphere, extending far out into space
- probably has frozen water
- Methane clouds
- probe to titan in 2005 landed in mud and found water ice, methane springs, rivers with islands
- icy “rocks”, “river” valleys
- Dunes hundreds of Kilometers long
13
Q
Uranus’ Moons
A
- More than 20 small ones, some irregular in shape, some retrograde
- Five midsized, Miranda, Ariel, Umbriel, Titania, Oberon
- All icy, with varied geological history
14
Q
Miranda
A
- Strange, very fractured surface, some cataclysmic event?
15
Q
Neptune’s Moons
A
- Five small inner moons near ring system
- Two larger moons, icy
- five smaller outer moons, retrograde
