Earth Sciences 1086F/G Lecture 15: chapter 15
13 Jan 2020
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1. Chapter 15: Saturn and Family
Saturn Missions:
o - Pioneer 11: first spacecraft visit to Saturn
- flew within 20,000 km of the planet’s cloud tops
o - Voyager 1 and Voyager 2: provided data for the recent Cassini-Huygens
mission
- they determined the hydrogen/helium ratio of the atmosphere - checked out
winds and atmosphere belt patterns
- found auroras at the poles
- got some good pictures of satellites and rings
o - Cassini-Huygens: first spacecraft to orbit Saturn
▪ - Cassini was built by NASA
▪ - the Huygens probe was built by the European Space Agency
▪ - used “gravity assist” boosts from other planets to get enough energy to
project itself all the
way to Saturn
▪ - it was the first spacecraft to explore the Saturn system of rings and
satellites from orbit
o - New Horizons: cut through the orbit of the Saturn system on the way to Pluto
Saturn: The Planet:
o - a lot less dense than Jupiter
o - Saturn rotates about as fast as Jupiter, but is almost twice as oblate
o - it has a small ‘rocky’ core, a thicker metallic hydrogen inner mantle, and the
rest is mostly
liquid hydrogen with an outermost 1000 km thick layer of atmosphere
o - Saturn is radiating 1.8 times as much energy as it gets from the sun
- this tells us heat is flowing out of its interior
Atmosphere:
o - about 91% of the atmosphere is hydrogen
o - 6% is helium
o - the rest consists of nitrogen, oxygen, carbon, and a few compounds including
water,
ammonia, and methane
o - the very outer layers are small amounts of hydrocarbons including acetylene,
ethane, propane, and methane
o - it’s atmosphere contains belt-zone circulation, which appears to arise in the
same way as that on Jupiter
o - zones — higher clouds formed by rising gas
o - belts — lower clouds formed by sinking gas
o - Saturn’s atmosphere is much colder than Jupiter’s
o - Saturn has fewer winds than Jupiter, but they are much stronger
- reason for this difference is not clear
- storms in the atmosphere are common
o - the clouds on Saturn form at about the same temperature as the clouds on
Jupiter
o - Saturn’s cloud pattern is much more uniform in colour than that of Jupiter and
with less
distinct divisions
o - scientists think there are 3 layers of clouds, depending on the temperature at
which various
Document Summary
Pioneer 11: first spacecraft visit to saturn. Flew within 20,000 km of the planet"s cloud tops. Voyager 1 and voyager 2: provided data for the recent cassini-huygens mission. They determined the hydrogen/helium ratio of the atmosphere - checked out winds and atmosphere belt patterns. Got some good pictures of satellites and rings. The huygens probe was built by the european space agency. Used gravity assist boosts from other planets to get enough energy to project itself all the way to saturn. It was the first spacecraft to explore the saturn system of rings and satellites from orbit. New horizons: cut through the orbit of the saturn system on the way to pluto. Saturn rotates about as fast as jupiter, but is almost twice as oblate. It has a small rocky" core, a thicker metallic hydrogen inner mantle, and the rest is mostly liquid hydrogen with an outermost 1000 km thick layer of atmosphere.
