Ariel is the brightest and third most massive of the 27 known moons of
Uranus. Discovered on 24 October 1851 by William Lassell, it is named
for a sky spirit in Alexander Pope's The Rape of the Lock and
Shakespeare's The Tempest. Like its parent planet, Ariel orbits on its
side, giving it an extreme seasonal cycle. As of 2011, almost all
knowledge of Ariel derives from a single flyby of Uranus performed by
the spacecraft Voyager 2 in 1986, which managed to image 35% of the
moon's surface. There are no plans at present to return to study the
moon in more detail. After Miranda, Ariel is the second-smallest of
Uranus's five round satellites, and the second-closest to its planet.
Among the smallest of the Solar System's 19 known spherical moons (it
ranks 14th among them in diameter), Ariel is composed of roughly equal
parts ice and rocky material. Like all of Uranus's moons, Ariel
probably formed from an accretion disk that surrounded the planet
shortly after its formation, and, like other large moons, it may be
differentiated, with an inner core of rock surrounded by a mantle of
ice. Ariel has a complex surface comprising extensive cratered terrain
cross-cut by a system of scarps, canyons and ridges. The surface shows
signs of more recent geological activity than other Uranian moons, most
likely due to tidal heating.
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Today's selected anniversaries:
Belgian clarinetist Adolphe Sax received a patent for the saxophone.
The United States Court of Private Land Claims ruled that the title
claimed by James Reavis to 18,600 sq mi (48,000 km2) in present-day
Arizona and New Mexico was "wholly fictitious and fraudulent".
Archduke Franz Ferdinand of Austria and his wife, Sophie, Duchess of
Hohenberg, were assassinated by Yugoslav nationalist Gavrilo Princip
during a motorcade in Sarajevo, sparking the outbreak of World War I.
In response to a police raid at the Stonewall Inn in New York City,
groups of gay and transgender people began to riot against New York
City Police officers, a watershed event for the worldwide gay rights
Seventy-three leading officials of Iran's Islamic Republic Party were
killed when a bomb exploded at the party's headquarters in Tehran.
Wiktionary's word of the day:
(psychology) A subjective feeling experienced in response to a thought
or other stimulus; mood, emotion, especially as demonstrated in
external physical signs
Wikiquote quote of the day:
Good laws lead to the making of better ones; bad ones bring about