Jupiter_Notes

Overview of Jovian Planets

• The Jovian planets, including Jupiter, Saturn, Uranus, and Neptune, are primarily studied through spacecraft rather than telescopes.

Spacecraft Missions

• Voyager 1 & 2

  • Launched in 1989.

  • Voyager 1 traveled from Jupiter to Saturn, while Voyager 2 journeyed from Saturn to Uranus and Neptune.

  • Both studied the electromagnetic field, as well as radio, visible, and infrared emissions. They continue to send data as they reach interstellar space.

• Galileo

  • Arrived at Jupiter in December 1995.

  • Studied Jupiter’s moons, atmospheric chemistry, and measurements of the planet itself.

• Cassini

  • Launched in 1997.

  • Focused on Saturn, its rings, and moons, notably Titan.

Characteristics of Jovian Planets

• These planets have greater mass than Earth but exhibit low density due to their huge gravitational forces that hold atmospheric gases.

• Their predominant composition is hydrogen and helium, with cores that might be rocky or icy.

• Jovian planets possess strong electromagnetic fields generated by their rotating mantles, emitting radio waves.

Rotation Axes and Speeds

• Each Jovian planet rotates at different speeds:

  • Jupiter: High latitudes take longer to rotate compared to the equator (6-minute difference).

  • Saturn: 27-minute difference in rotation speed.

  • Uranus: 2-hour difference.

  • Neptune: 6-hour difference.

Internal Structure of Jovian Planets

• Observation of internal structures obscured by cloud layers:

  • Jupiter and Saturn are believed to have a metallic hydrogen layer.

  • Uranus and Neptune have a slushy layer of water as part of their mantles.

Rings of Jovian Planets

• All four Jovian planets have ring systems composed of particles and small moonlets.

• Rings may result from the destruction of moons or from material that could not coalesce into moons due to strong gravitational tidal forces.

Jupiter's Observational Features

• Jupiter is the third brightest object in the night sky, displaying distinct bands and ovals alongside many moons.

• Atmospheric Characteristics:

  • Shows parallel cloud bands with colors including yellow, blue, brown, tan, and red.

  • The Great Red Spot is a gargantuan hurricane, three times the size of Earth, existing for hundreds of years.

  • Composition: 86% hydrogen, 14% helium, with traces of methane, ammonia, and water vapor.

Energy Emission and Atmospheric Structure

• Jupiter emits more energy than it receives, potential sources include:

  • Internal heat from formation.

  • Ultraviolet energy absorption.

  • Magnetosphere effects.

  • Energy from electrical storms.

• Atmospheric layers consist of troposphere with clouds and varying ice, exhibiting temperature gradients as altitude increases.

The Great Red Spot

• A persistent storm approximately 35,000 km in diameter, rotating around Jupiter due to prevailing wind patterns.

• Color intensity correlates with storm strength, with red indicating strong storms.

Interior Structure of Jupiter

• Composition: An icy core ten times larger than Earth's core, surrounded by metallic hydrogen mantle, a good thermal conductor.

• Jupiter has a magnetic field over 20,000 times stronger than Earth’s and larger than the Sun’s, creating auroras.

• Jupiter's temperature averages 125 Kelvin, with various theories about its heat source:

  • Heat retention within clouds.

  • Leftover heat from its formation.

  • Ongoing heat release from within.

Moons of Jupiter

• Moons are categorized into three groups:

  • Large moons (>2500 km): 6 total, comparable in size to Earth’s Moon and possess geological activity.

  • Medium moons (400-1500 km): 12 learned, heavily cratered and with likely rock-water compositions.

  • Small moons (<300 km): Many irregularly shaped and primarily ice.

• Jupiter hosts 64 moons with four notable Galilean moons:

  • Io: Most geologically active, with over 80 active volcanoes, thin sulfur dioxide atmosphere, and smooth terrain due to volcanic activity.

  • Europa: Covered in ice, believed to enclose an ocean potentially harboring life. Ice covers cracks, and it has a weak magnetic field linked to a saline water layer beneath its icy crust.

  • Ganymede: Larger than Mercury, features an internal metallic core and fractured surface indicative of water activity, no atmosphere.

  • Callisto: Has more craters than Ganymede, shows less tectonic reformation, with meteorite impacts leading to ice melting and freezing.