1. The Jovian Planets
Huge worlds, heavily mantled in gas at the time of the formation of the Solar System.

2. The Galilean Satellites
Jupiter has four planetary-sized moons first seen by Galileo and easily visible in binoculars.

3. The Galilean Satellites
Jupiter has four planetary-sized moons first seen by Galileo and easily visible in binoculars.

4. Io and Geological Activity
Io, being similar in size to the Earth's Moon, might be expected to be a geologically dead world.

5. Io and Geological Activity
It turns out to be the most volcanically active world in the Solar System.

6. Io and Geological Activity
It turns out to be the most volcanically active world in the Solar System.
No impact craters!
Coloration from Sulfur and sulfur compounds.
Density = 3.0 g/cm3
mostly rock
formed in a “warm location”?
ices baked away?

10. Io's “Atmosphere”
The volcanic activity produces a continuously escaping tenuous atmosphere of sulfur and sodium near Io, and a “torus” of this material around Jupiter.

11. Heating Io Internally – Tidal Stretching
Io has an elliptical orbit due to tugs from the other large Galilean satellites.
The solid body of Io experiences significant, regular tidal distortion as a result (the orbit takes just under 2 days)

12. Heating Io Internally – Tidal Stretching
The tidal stretching heats the interior of Io significantly, so much so that volcanism is rampant.

13. Europa and Tidal Heating
Europa is the next Galilean satellite out from Jupiter
Craters are rare on Europa as well
tidal heating is much weaker – greater distance / slower orbit
Europa, however has an icy surface – easier to melt.

14. Europa and Tidal Heating
Europa is the next Galilean satellite out from Jupiter
Craters are rare on Europa as well
tidal heating is much weaker – greater distance / slower orbit
Europa, however has an icy surface – easier to melt.

15. Europa and Tidal Heating
Europa also has a density close to 3.0 g/cc.
The outer layer of ice is the top of a true frozen-over “ocean” about 100 kilometers deep.
Weak tidal heating combined with radioactive decay keep Europa warm enough keep the ocean liquid below a few kilometers of icy crust.
Liquid water in the outer solar system!!!

16. Europa and Tidal Heating
Europa also has a density close to 3.0 g/cc.
The outer layer of ice is the top of a true frozen-over “ocean” about 100 kilometers deep.
Weak tidal heating combined with radioactive decay keep Europa warm enough keep the ocean liquid below a few kilometers of icy crust.
Liquid water in the outer solar system!!!

17. Europa as an Abode for Life
Europa's ocean is likely habitable if life formed there.
Interestingly, it is now thought that life on Earth may have originated near submerged volcanic vents.
The most primitive life forms on Earth thrive in extreme environments – e.g. boiling water.

18. Europa as an Abode for Life
Europa's ocean is likely habitable if life formed there.
Interestingly, it is now thought that life on Earth may have originated near submerged volcanic vents.
The most primitive life forms on Earth thrive in extreme environments – e.g. boiling water.

20. Enceladus
Tidal heating again?

23. Composition of the Jovian Planets
Jupiter and Saturn attracted so much gas gravitationally during formation that the have a composition that largely matches the Sun
Mostly hydrogen, some helium, and a a tiny fraction of the other elements.

24. Composition of the Jovian Planets
Jupiter and Saturn attracted so much gas gravitationally during formation that the have a composition that largely matches the Sun
Mostly hydrogen, some helium, and a a tiny fraction of the other elements.
- Uranus and Neptune are also dominate by Hydrogen and Helium, but not to the degree that Jupiter and Saturn are.
- The significant portion of their mass likely made up by water leads to Uranus and Neptune being called “ice giants”

25. The Galilean Satellites
Jupiter has four planetary-sized moons first seen by Galileo and easily visible in binoculars.