Jupiter and Saturn - In Depth Notes

Jupiter and Saturn

• General Characteristics

  • Images show relative sizes of Jupiter and Saturn, with distinct features.
  • Jupiter:
  • Dark belts (low-pressure zones) and light zones (high-pressure zones) create a banded appearance.
  • Dark belts are hypothesized to contain hydrocarbons that darken under UV light.
  • Lighter zones consist of high-altitude ammonia ice clouds reflecting sunlight.
  • Saturn:
  • Exhibits similar but more muted belt-zone circulation than Jupiter.

• Belt-zone Circulation

  • This atmospheric structure results from convection where warm air rises and cold air falls.
  • Influenced by the Coriolis effect due to rapid rotation.

Wind Speeds and Storms

• Wind Characteristics

  • Extreme wind speeds observed:
  • Jupiter: up to 620 ext{ km/h} (390 ext{ mph}).
  • Saturn: up to 1,800 ext{ km/h} (1,100 ext{ mph}).
  • For reference, hurricane winds on Earth reach a maximum of 400 ext{ km/h} (250 ext{ mph}).

• Great Red Spot (Jupiter)

  • A massive storm observed for over 300 years, with continuous observation for the last 200 years.
  • Current dimensions: oval shape, 25,000 ext{ km} (length) and 12,000 ext{ km} (width).
  • Two Earth-sized regions could fit within it.

• Little Red Spot (Red Spot Jr)

  • Formed from merging three storms in 1998, intensified in 2006.
  • The reason for its red color is under investigation, possibly due to material from lower atmosphere.

Storm Events on Saturn

• Major Storm (2010)

  • A storm with a vortex larger than Jupiter's Red Spot formed in Saturn's northern hemisphere.
  • Released ethylene gas and significantly altered local temperatures.

• Hexagonal Jet Stream

  • Unstable hexagonal feature observed at Saturn's north pole; its origins are under research.

Atmospheric Composition

• Main Components

  • Jupiter and Saturn's atmospheres primarily consist of hydrogen (H) and helium (He).
  • Layered structures include:
  • Ammonia ice (NH_3)
  • Ammonium hydrosulfide (NH_4SH)
  • Water (H_2O)

• Ice Clouds

  • Ice exists as aerosols with observed colors arising from chemical reactions involving lightning and sunlight.
  • Saturn has thicker ice layers due to lower gravitational pull.

Interior Structures

• Core Composition

  • Jupiter and Saturn both possess rocky cores surrounded by layers of metallic hydrogen, liquid hydrogen, and gaseous hydrogen.
  • The transition between gaseous and liquid hydrogen occurs at various depths.

• Physical Properties

  • Similar internal pressures and temperatures, resulting in a smooth transition to metallic hydrogen, a good electric conductor responsible for their magnetospheres.

Specifics for Jupiter

• Key Characteristics
  • At rac{1}{4} R_{Jupiter} within its interior, pressure forms metallic hydrogen.
  • Contains approximately 30 M_{Earth} of heavy elements with most suspended in convective hydrogen.
  • Density: Specific gravity (SG) of 1.33, which is about rac{1}{4} that of Earth.

Specifics for Saturn

• Key Characteristics
  • Lesser amount of metallic hydrogen due to smaller mass leading to lower pressure.
  • Saturn radiates about 2.5 times more energy than it receives from the Sun, a phenomenon requiring further explanation.

Magnetism

• Conditions for a Magnetosphere
  • Need conductive fluid, convection of that fluid, and rotation around an axis.
  • Both Jupiter and Saturn have significant magnetic fields and large magnetospheres, stronger than Earth's.
  • Jupiter's magnetic field is approximately 20,000 times stronger than Earth's.

Jupiter's Magnetosphere**

• Radiation Levels
  • Spacecraft enter intense radiation zones leading to significant radiation exposure, harmful to electronics.
  • Auroras on Jupiter significantly exceed those on Earth in luminosity (up to 1000 times brighter).

Comet Impact (Shoemaker-Levy 9)

• Observed in 1994, this comet was captured by Jupiter’s gravity, leading to its fragmentation and impact with the planet.
• Significant for being one of the first major astronomical events shared live via the Internet.
• Jupiter serves an important protective role for Earth by attracting comets and asteroids that might endanger our planet.