All About Uranus

• Uranus was the first planet discovered using a telescope.
• It is an ice giant, not a gas giant, comprised mostly of flowing ices over a solid core.
• Uranus is very cold and windy.
• Named after the Greek god of the sky, who was the father of Kronos (Saturn).

Rings

• It has 13 faint rings.
• The inner rings are narrow and dark.
• The outer rings are brightly colored and more visible.

Rotation and Orbit

• Uranus rotates at a nearly 90-degree angle from its orbital plane.
• It appears to spin on its side due to this tilt.
• Uranus rotates in the opposite direction of most planets, similar to Venus.
• Unlike any other planet, it rotates on its side.
• One rotation lasts 17 hours.
• One revolution around the sun takes 84 Earth years.

Atmosphere

• Uranus appears blue-green because of large amounts of methane.
• It has a thick atmosphere made of methane, hydrogen, and helium.
• Uranus lacks a true surface and is mostly swirling fluids.
• Extremely high pressures and temperatures would destroy a metal spacecraft.

Moons

• Uranus has 28 known moons.
• Five major moons: Miranda, Ariel, Umbriel, Titania, and Oberon.
• Inner moons (observed by Voyager 2) are roughly half water ice and half rock.
• Moons outside Oberon's orbit are likely captured asteroids.

Exploration

• Voyager 2 is the only spacecraft to have visited Uranus.
• Voyager 2 flew past Uranus after traveling 3 billion kilometers in nine years.
• Voyager 2 gathered information about the planet's rings and moons in only six hours.
• Voyager 2 discovered 10 new moons, two new rings, and a magnetic field stronger than Saturn's.
• Observations from the Hubble Space Telescope and powerful ground-based telescopes have also provided information about Uranus.
• In March 2011, the New Horizons spacecraft crossed Uranus' orbit on its way to Pluto.
• New Horizons did not take any images of Uranus.
• The spacecraft remains mostly inactive during its eight-year journey from Jupiter to Pluto, waking up for 50 days each year for instrument checkups.