1. Satellietes orbiting the other planets

2. How much can we learn from satellites orbiting other planets?

3. Galilean Moons of Jupiter

4. Galileo discovered these four satellites in January of 1610
This was a shock as it was the first stellar body discovered that orbited something other than us (according to Ptolemaic system)

6. Saturn has prominent moons, too

7. The “top 7” moons in the solar system
Satellite
Planet
Diameter(km)
Mass (relative to Moon)
Ganymede
Jupiter
5262
2.03
Titan
Saturn
5150
1.83
Callisto
4820
1.46 Io
3640
1.21
Moon
Earth
3476
1.00
Europa
3122
0.66
Triton
Neptune
2700
0.29

8. Moons of Jupiter
We knew almost nothing about these satellites until we launched the Voyager spacecraft in the 1970s Io
Europa
Ganymede
Callisto
8 others known before space age
A total of 67 now known (mostly tiny)

9. The Galilean satellites of Jupiter (cont)

10. Callisto: most distant of Galilean satellites
Distance from Jupiter = thousand km; diameter = 4820km

11. Ganymede: largest moon in solar system
Distance from Jupiter = 1080 thousand km, diameter = 5268

12. Ganymede is the only moon with a magnetic field
Radiogenic heating has produced radio waves. It also contains water

13. Europa and the origins of life in the universe
Distance from Jupiter = 671 thousand km, diameter = 3122 km

14. Cracks in the ice crust of Europa
Evidence of water flows from the interior

15. Views of the cracks from Galileo spacecraft

16. Speculations on interior structure of Europa

17. A future Europa Lander could tell us much about the possible subsurface ocean of Europa

18. Speculation on Europa of 4.5 Gyr ago

19. Io … world of rapid changes
Distance from Jupiter = 422 thousand kilometers, diameter = 2263 km
Active Volcano

20. Io
Comparisons between Voyager (late 70s) and Galileo (mid 90s) showed geographical changes on Io (see figure 14.11)

21. Changes on Io:

22. We learned from studying the Galilean moons that the geology is driven by tidal flexing and squeezing by gravity

23. Uranus’ Moons
Named after William Shakespeare and Alexander Pope characters
There are 15 known moons

24. Uranus’ Moons MIRANDA: Surface is a weird mix of old and new terrain
It has been proposed than it was shattered and reassembled in this way
There was not enough heat to fuse it smoothly together

25. Uranus’ Moons ARIEL: Youngest surface of the Uranian Satellites
There is evidence of tectonic activity
It has faults over 10 km deep

26. Uranus’ Moons TITANIA: Largest of Uranus’ moons
Has faults up to 100 km across
Has a heavily cratered surface

27. Neptune’s Moons TRITON:
Has thin atmosphere, geysers, and strange “cantaloupe terrain”
Diameter: 3000km

28. Neptune’s Moons Proteus:
Second largest moon of Neptune discovered by Voyager
Surprisingly, Neried, Neptune’s third largest moon was discovered from the ground before Proteus

29. Phobos and Deimos, moons of Mars
The only terrestrial planet satellites besides the Moon
Provide insight into formation of solar system