Uranus (Planet)

The seventh planet from the Sun — the first planet discovered with a telescope, and the most extreme in the Solar System for its sideways tilt. An ice giant of cyan methane clouds, orbiting in permanent half-century seasons. Mythological counterpart: myth-ouranos. Crossing note: crossing-uranus-ouranos.

Key Properties

The Sideways Planet

Uranus's axial tilt of 97.77° means it orbits essentially on its side — the poles point roughly toward (and away from) the Sun. The consequence: each pole receives 42 years of continuous sunlight, then 42 years of continuous darkness. When Voyager 2 visited in 1986, the south pole was pointed toward the Sun.

Despite this extreme tilt, Uranus's atmosphere is paradoxically the coldest in the Solar System — it radiates almost no internal heat, unlike Jupiter or Saturn. The reason for this thermal suppression is unknown and is one of the planet's major mysteries.

Discovery and Naming

William Herschel observed Uranus on 13 March 1781 with a 6.2-inch telescope in Bath, England. He initially thought it was a comet. Confirmation as a planet followed. Herschel named it Georgium Sidus ("George's Star") in honour of King George III — a politically motivated choice that the rest of Europe refused.

French astronomers called it "Herschel." The name Uranus — proposed by Johann Bode, following the convention of naming planets after Roman/Greek deities — was adopted slowly and didn't fully replace rivals until around 1850.

The logic of the name: if Jupiter/Zeus overthrew Saturn/Cronus, who overthrew Uranus/Ouranos, then the planetary sequence outward from Jupiter (Saturn, Uranus) mirrors the mythological succession backwards in time.

Moons — Shakespeare and Pope

Uranus's 29 moons are uniquely named from characters in Shakespeare and Alexander Pope — the only major planet system not drawing on Greco-Roman mythology. The five major moons:

• Miranda — character in *The Tempest*; has fault canyons 20 km deep
• Ariel — *The Tempest* and *The Rape of the Lock*; youngest surface
• Umbriel — *The Rape of the Lock*; oldest surface
• Titania — Queen of the Fairies in *A Midsummer Night's Dream*; largest moon
• Oberon — King of the Fairies in *A Midsummer Night's Dream*

The Rings

Uranus has 13 ring systems — discovered serendipitously on 10 March 1977 when astronomers were observing a stellar occultation to study the atmosphere and noticed the star dimming briefly before and after disappearing behind Uranus. The rings are made of extremely dark particles reflecting only 2% of light — darker than coal. The outermost ring is blue, inner rings grey.