As of 2019, much of the detailed knowledge of Ariel derives from a single flyby of Uranus performed by the space probe Voyager 2 in 1986, which managed to image around 35% of the moon's surface.

There are no active plans at present to return to study the moon in more detail, although various concepts such as a Uranus Orbiter and Probe have been proposed.

Among the smallest of the Solar System's 20 known spherical moons (it ranks 14th among them in diameter), it is believed to be composed of roughly equal parts ice and rocky material.

Ariel has a complex surface consisting of 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.

Discovered on 24 October 1851 by William Lassell, it is named for a sky spirit in Alexander Pope's 1712 poem The Rape of the Lock and Shakespeare's The Tempest.

[15][16][17] All of Uranus's moons are named after characters from the works of William Shakespeare or Alexander Pope's The Rape of the Lock.

The moon's density is 1.52 g/cm3, which indicates that it consists of roughly equal parts water ice and a dense non-ice component.

[8] The cause of this asymmetry is not known, but it may be related to bombardment by charged particles from Uranus's magnetosphere, which is stronger on the trailing hemisphere (due to the plasma's co-rotation).

It might be produced locally from carbonates or organic materials under the influence of the energetic charged particles coming from Uranus's magnetosphere or solar ultraviolet radiation.

[30] Given its size, rock/ice composition and the possible presence of salt or ammonia in solution to lower the freezing point of water, Ariel's interior may be differentiated into a rocky core surrounded by an icy mantle.

[37] It is intersected by a network of scarps, canyons (graben), and narrow ridges mainly occurring in Ariel's mid-southern latitudes.

[37] The canyons, known as chasmata,[39] probably represent graben formed by extensional faulting, which resulted from global tensional stresses caused by the freezing of water (or aqueous ammonia) in the moon's interior (see below).

[22] The longest canyon is Kachina Chasma, at over 620 km in length (the feature extends into the hemisphere of Ariel that Voyager 2 did not see illuminated).

[37] The youngest terrain observed on Ariel are the plains: relatively low-lying smooth areas that must have formed over a long period of time, judging by their varying levels of cratering.

[37] A few of these areas appear to be less than 100 million years old, suggesting that Ariel may still be geologically active in spite of its relatively small size and lack of current tidal heating.

[37] Ariel's past geologic activity is believed to have been driven by tidal heating at a time when its orbit was more eccentric than currently.

[37] It has been suggested that a circular depression 245 km in diameter located at 10°S 30°E is a large, highly degraded impact structure.

[44] The moons that formed in such a subnebula would contain less water ice (with CO and N2 trapped as clathrate) and more rock, explaining the higher density.

[44] Models suggest that impacts accompanying accretion caused heating of Ariel's outer layer, reaching a maximum temperature of around 195 K at a depth of about 31 km.

[45] After the end of formation, the subsurface layer cooled, while the interior of Ariel heated due to decay of radioactive elements present in its rocks.

This caused strong extensional stresses in the moon's crust reaching estimates of 30 MPa, which may have led to cracking.

[45] The melting may have led to the separation of ice from rocks and formation of a rocky core surrounded by an icy mantle.

[45] More recent analysis concluded that an active ocean is probable for the 4 largest moons of Uranus; specifically including Ariel.

[48] The only close-up images of Ariel were obtained by the Voyager 2 probe, which photographed the moon during its flyby of Uranus in January 1986.

[51] On 26 July 2006, the Hubble Space Telescope captured a rare transit made by Ariel on Uranus, which cast a shadow that could be seen on the Uranian cloud tops.