Uranus_Notes

Discovery of Uranus

• Discovered in 1781 by William Herschel.

• Originally intended to be named "George’s Star" after King George.

• Officially named Uranus after its planetary status.

• Appears as a faint star to the naked eye; looks like a green dot through a telescope.

• Lacks visible features like bands or spots common in other planets.

Voyager 2 Mission

• Voyager 2 was sent to explore Uranus.

• Uranus does not conform to Kepler's planetary laws, indicating external gravitational influences from Neptune.

Unique Tilt and Seasons

• Uranus is tilted on its side at 98 degrees, with its poles facing the Sun.

• This unique tilt leads to extreme seasons: 42 years of continuous light followed by 42 years of darkness.

• Hypothesized that a collision with another celestial body caused this tilt, but certainty remains elusive.

Composition of Uranus

• Atmospheric Composition:

  • 84% Hydrogen

  • 14% Helium

  • 3% Methane

• Methane contributes to its distinctive color.

• Atmospheric features include few clouds in the upper atmosphere and a pervasive haze.

Atmospheric Conditions

• Wind speeds range between 200-500 km/h.

• Uranus has a smaller mass compared to other gas giants.

• Internal structure includes:

  • Rocky core

  • Slushy mantle

  • Molecular hydrogen crust

• Exhibits a strong magnetic field, although weaker than Jupiter's.

• Does not produce internal energy; balances energy received with radiation emitted.

Rings and Moons

• Discovered in 1977, Uranus has 11 narrow, dark, widely spaced rings.

• Contains 27 moons in total, five of which are medium-sized.

• Moons exhibit characteristics suggesting a lack of water:

  • Oberon: Heavily cratered, similar to Rhea (a moon of Saturn).

  • Miranda: Features ridges, valleys, and faults, composed of compressed gravel.

  • Ariel: Has cracks, indicating potential volcanic activity or impact scars.

  • Umbriel: Heavily cratered, akin to Rhea.

  • Titania: Also heavily cratered and resembles Rhea.