Uranus

Uranus is the seventh planet from the Sun, an ice giant with a blue-green atmosphere and an unusually tilted rotation axis. William Herschel discovered it in 1781.

Axial tilt: The angle between a body's rotational axis and the direction perpendicular to its orbital plane. Uranus's 98-degree axial tilt makes its poles alternately face the Sun during its long orbit.
William Herschel: A German-born British astronomer who discovered Uranus in 1781 and made major observations of stars and nebulae. Herschel first recognized Uranus as a moving object beyond Saturn.
Planetary migration: The movement of planets from their original orbits, often through interactions with a protoplanetary disk or other planets. Migration models use Uranus's orbit and the outer planets' arrangement to reconstruct Solar System history.
Neptune: The eighth planet from the Sun, an ice giant with a dynamic atmosphere and a strong internal heat source. Neptune resembles Uranus in size and composition but emits substantially more internal heat.
Uranian atmosphere: The gaseous envelope of Uranus, composed mainly of hydrogen, helium, and methane above a deeper volatile-rich interior. Methane in the upper atmosphere absorbs red light, contributing to Uranus's blue-green appearance.
Uranus's discovery: The 1781 identification of Uranus as a planet by William Herschel, the first planet discovered with a telescope. The discovery established that the Solar System extended beyond the planets known since antiquity.
Nice model: A model of Solar System evolution in which the giant planets underwent orbital rearrangement and scattering. The model explains how Uranus may have reached its present orbit during early planetary instability.
Jupiter: The largest planet in the Solar System, a hydrogen-helium gas giant with many moons and a powerful magnetosphere. Jupiter's immense size and rapid rotation contrast with Uranus's ice-rich interior and extreme axial tilt.
Uranus's magnetosphere: The region around Uranus shaped by its magnetic field and interaction with the solar wind. Its magnetic axis is strongly tilted and offset from the planet's center, producing a lopsided magnetosphere.
Johann Elert Bode: A German astronomer who promoted the name Uranus and helped popularize a numerical relation among planetary distances. Bode advocated the name that became standard for Herschel's newly discovered planet.

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