1. Jupiter and Saturn – Size and Mass
Size – 11  Earth (Jupiter) and 9  Earth (Saturn)
Mass – 318  Earth (Jupiter) and 95  Earth (Saturn)
Jupiter significantly less dense than Earth
Saturn much less dense than Earth
Orbits:
5.2 AU, 9.6 AU
12 years, 29 years

2. Jupiter and Saturn – Rotation and Shape
Rotation is fast!
10 hours Jupiter
10.6 hours Saturn
Q. 41: Jupiter and Saturn’s Rapid Rotation

3. Jupiter and Saturn – Composition
We have few clues to composition and distribution of interior
Gravity (density), shape, magnetic fields
We can’t duplicate comparable pressures on Earth
Q. 42: Jupiter and Saturn’s Magnetic Fields
Hydrogen and helium
Gas/liquid
Liquid metallic hydrogen
Liquid ices (water & others)
Rock/metal

4. Jupiter and Saturn – Magnetic Fields
Jupiter and Saturn each have enormous magnetic fields
Jupiter’s significantly bigger than Saturn’s
Generated in metallic hydrogen layer
Traps large amounts of charged particles from Io
Dangerous to spacecraft / computer

5. Jupiter and Saturn – Still Forming?
Jupiter and Saturn are so huge, that it takes a long time for them to lose internal heat
They are probably still contracting and cooling
Gravitational energy  Heat  Thermal radiation
They may not be completely differentiated yet
Helium is heavier than hydrogen
Drops of helium form within the hydrogen layers
They fall towards the center
Gravitational energy  Heat  Thermal radiation
Jupiter emits 1.65 time more heat than it gets from the Sun
Saturn emits 3 times more heat than it gets from the Sun

6. Jupiter and Saturn – Basic Climate
They are both cold – Jupiter 165 K, Saturn 134 K
Heat rising from center – convection
Powered from inside, not outside as on Earth
Fast rotation turns these into powerful winds heading east and west
Creates Bands and Zones

7. Jupiter and Saturn – Colors
Hydrogen and helium are essentially transparent
Other minor constituents produce ice clouds at the correct temperature
Ammonia (NH3) at coldest temperatures
Ammonium hydrosulfide (NH4SH) a bit higher
Water (H2O) at highest
On different planets, these will form at different altitudes
Shallow on warm Jupiter
Deeper on cold Saturn
Deeper still on Uranus and Neptune
The deeper they are, the harder they are to see

8. Jupiter and Saturn – Colors
Jupiter’s clouds shallow – easily seen
Saturn’s clouds deep – hard to see

9. Jupiter and Saturn – Bands
Warm gasses rising from inside make bright “Zones”?
Cool gasses falling back in make dark “Belts” ?
Bands are at different depths on different planets

10. Jupiter’s Bands Infrared Visible Zones - lighter, cooler clouds
Belts - darker, warmer clouds

11. Jupiter’s Weather Patterns

12. Winds on Jupiter and Saturn
Q. 43: Measuring the Rotation of Jupiter and Saturn

13. Storms on Jupiter

14. Storms on Saturn

15. Polar Regions on Jupiter and Saturn
Saturn has a strange, hexagon-shaped storm at its pole
Jupiter, in contrast, loses its band structure at north pole

16. Jupiter and Saturn – Colors
Hydrogen and Helium are essentially transparent
Other minor constituents produce ice clouds at the correct temperature
Ammonia (NH3) at coldest temperatures
Ammonium Hydrosulfide (NH4SH) a bit higher
Water (H2O) at highest
On different planets, these will form at different altitudes
Shallow on warm Jupiter
Deeper on cold Saturn
Deeper still on Uranus and Neptune
The deeper they are, the harder they are to see

17. Jupiter’s Great Red Spot
Jupiter’s super storm
Larger than Earth
Has persisted for > 300 years
Changes color and size

18. Red and Red Jr.
New storms constantly appearing, disappearing, and merging
In 1998, two of the smaller storms merged
Later, it turned red
Red Jr.
Red

19. Lightning on Saturn and Jupiter
As on Earth, storms can generate lightning
Images below are from Jupiter
Also detected on Saturn

20. Uranus and Neptune How We Know What We Know
Voyager 2
Uranus 1986
Neptune 1989
Ongoing Telescope observations
Neptune faint bands plus clouds
Uranus Featureless blue ball

21. Uranus and Neptune – Basic Facts
Size – About 4  Earth size, Uranus bigger
A lot smaller than Jupiter, Saturn
Mass – 14.5  Earth (Uranus), 17  Earth (Neptune)
Substantially lower density
Orbits – 19 AU (Uranus), 30 AU (Neptune)
84 y (Uranus), 165 y (Neptune)
Rotation – a little fast
17 hours (Uranus), 16 hours (Neptune)
Temperature – cold
76 K (Uranus), 72 K (Neptune)

22. Uranus and Neptune – Composition
No metallic hydrogen layer
“Ices” include water, methane, and ammonia
AST0812.jpg
Hydrogen & Helium w/ Methane
Uranus
Neptune
Rock/Metal
Liquid Ices
Ices have salts, which make them conductive
These are where the magnetic fields are generated

23. Uranus and Neptune – Internal Heat
Both give off more heat than they get from the Sun
Uranus – 1.1 times heat from Sun
Neptune – 2.6 times heat from Sun
Source of this heat is unknown

24. Magnetic Field and Axis of Rotation
Normally (first 6 planets), magnetic field will be centered on the planet, and point near the geographic pole
Not so for Uranus and Neptune!
No one knows why
Most planets rotate same way they go around the Sun
Axial tilt:
Jupiter: 3
Saturn: 
Uranus: 98!
Neptune: 28
Why is Uranus tilted?