Lecture 13

Question 1

Formation of the Jovian planets

Answer 1

-Frozen H-compounds formed planetesimals -> build-up proto-planets
-Massive planets gravitationally attract H and He gas
- Solar nebula are less dense further out so it takes a longer time to accumulate mass

Question 2

Why does Jupiter (and the other Jovian planets) emit more heat than received by the sun?

Answer 2

Due to the continued contraction of the planet

Question 3

Atmospheric structure and chemistry of the Jovian planets

Answer 3

-the atmosphere contains similar regions such as a stratosphere and troposphere
-the features persist for longer due to there being no friction on the surface

Question 4

Magnetic fields of the Jovian planets

Answer 4

Electrical conduction due to metallic hydrogen

Question 5

Formation of moon and ring systems on the Jovian planets

Answer 5

-Tidal forces near the planet prevent small moonlets from accreting into larger moons
-Moonlets are disrupted by impacts
-Ongoing impacts blast off dust to form the rings

Question 6

Two categories of moons

Answer 6

1) Formed in an accretion disk- tend to be larger, have regular orbits, surfaces, icy
2) Captured moons- smaller, irregular shapes, little geological activity, irregular orbits

Question 7

Why are the orbits of the Galilean moons elliptical?

Answer 7

The ‘tugs’ all add up so that the orbits are elliptical. That is, they are locked in an orbital resonance where they all align every seven days and the recurring tugs cause the orbits to be elliptical.

Question 8

Europa’s water

Answer 8

Underneath the icy crust, Europa has more than twice the water of Earth. These oceans are very salty and warmed by Jupiter’s tidal forces.

Question 9

What are the wavy edges/gaps in rings caused by?

Answer 9

Small satellites that orbit the rings.