Geol 1420 Chapter 12.1

Chapter 12: Saturn

12.1 Orbital and Physical Properties

  • Radius: 60,000 km

  • Mass: 5.7imes1026extkg5.7 imes 10^{26} ext{ kg}

  • Density: 700 kg/m³ — less than water!

  • Rotation:
      - Extremely rapid and differential rotation.
      - Causes significant flattening of Saturn, making it noticeably oblate.

  • Rings:
      - Very prominent and well-known feature.
      - Rings are wide but extremely thin compared to their extent.

Visual Observations

  • During Saturn’s 29.5-year orbital period, portions of its rings may appear to vanish
      - This occurs when Earth passes through the plane of the rings, causing an edge-on view.

12.2 Saturn’s Atmosphere

  • Composition:
      - Dominated by molecular hydrogen and helium.
      - Contains trace amounts of methane and ammonia.
      - Helium fraction on Saturn is significantly lower than that of Jupiter.

  • Color Characteristics:
      - Atmospheric coloration is more subdued compared to Jupiter, despite similar zonal and band structures.

  • Cloud Layers:
      - Atmosphere contains three distinct cloud layers.
      - These cloud layers are generally thicker than those on Jupiter, resulting in visibility primarily only of the topmost layer.

  • Wind Patterns:
      - Exhibits zonal flow similar to Jupiter, characterized by bands of wind in opposite directions.

  • Storm Activity:
      - Jupiter-style spots can develop into significant storms on Saturn but may dissipate quickly.   - Close-up observations reveal the existence of a polar vortex at Saturn's south pole.   - Large vortices are present at both poles, attributed to the presence of jet streams.