Introduction to the galliean moons

Overview of the Galilean Moons

• The Galilean moons of Jupiter are:

  • Io

  • Europa

  • Ganymede

  • Callisto

• Discovered by Galileo in the 1600s.

• Identified by their circular orbits that are prograde (orbiting in the expected direction).

Orbital Characteristics

• All moons orbit in the same equatorial plane as Jupiter.

• Orbits increase in width the further they are from Jupiter (similar to planet distances from the Sun).

Individual Moons

Europa

• Size: Smaller than Earth's Moon.

• Surface: Thought to have an ice crust approximately 100 to 200 kilometers thick.

• Core and Mantle: Possible iron core with a rocky mantle.

Io

• Core: Believed to have an iron core.

• Mantle: Possible rocky composition, similar to our Moon.

Ganymede

• Size: Larger than Mercury, making it the largest moon in the solar system.

• Core: May comprise a smaller metallic core with a mafic (rocky) mantle.

• Density: Exhibits lower density, suggesting a significant amount of water or ice in its composition.

Callisto

• Composition: Predominantly solid ice.

• Structure: Lacks any layers or differentiation; theorized to have no distinct core or mantle, merely solid ice throughout.

Density Trends

• Density Variation: Trends show that densities of the moons decrease as the distance from Jupiter increases (paralleling solar system trends with planets and the Sun).