1. Giant Moons

2. Galilean Satellites Galileo saw four moons around Jupiter in 1610.
Support for Kepler’s laws.
These large moons were once thought to be like Earth’s.
All very different Io
Europa
Ganymede
Callisto
Galileo mission

3. Io Io is the solar system’s most active object.
The surface is covered in volcanos and geysers that spew dust into space.
The heat is generated from Jupiter’s tidal force.

4. Europa Europa has more water than Earth.
There is an ice layer covering a salty ocean.
Europa has a thin oxygen atmosphere.
Icy cracks on Europa

5. Ganymede Ganymede is larger than Mercury.
It has a magnetic field due to a molten iron core.
Ganymede shows craters and tectonics on the surface.
Water ice fills craters on the surface.

6. Callisto Callisto is almost as large as Mercury.
It also has ice filled craters.
Callisto has a weak magnetic field, but no core.
There is evidence that there is a deep subsurface ocean.

7. Titan Titan is the largest moon of Saturn.
Larger than Mercury
The planet is covered in clouds and has an atmosphere thicker than Earth.
Methane and ethane rain

8. Uranian Moons Miranda (470 km across) Titania (1580 km across)
Huge fault canyons (20 km)
Shattered as many as 5 times
Titania (1580 km across)
Many surface faults
1600 km canyon

9. Triton Triton is the largest moon of Neptune (2700 km).
It is the coldest known object in the solar system (-235 ºC).
It has a thin atmosphere and clouds of frozen nitrogen.