The Kachina Chasmata are the longest

canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...

or system of canyons on the surface of the Uranian moon

Ariel Ariel may refer to: Film and television *Ariel Award, a Mexican Academy of Film award * ''Ariel'' (film), a 1988 Finnish film by Aki Kaurismäki * ''ARIEL Visual'' and ''ARIEL Deluxe'', 1989 and 1991 anime video series based on the novel series ...

. The name comes from a

spirit Spirit or spirits may refer to: Liquor and other volatile liquids * Spirits, a.k.a. liquor, distilled alcoholic drinks * Spirit or tincture, an extract of plant or animal material dissolved in ethanol * Volatile (especially flammable) liquids, ...

Hopi mythology The Hopi maintain a complex religious and mythological tradition stretching back over centuries. However, it is difficult to definitively state what all Hopis as a group believe. Like the oral traditions of many other societies, Hopi mythology is ...

. The 622 km long and 50 km wide chasmata arise from a system of

normal fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

s running from the north-west to south-east. The faults bound down-dropped

crustal blocks Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by tectonic and localized stresses in Earth's crust. Large areas of bedrock are broken up into blocks by faults. Blocks are characterized by rela ...

forming structures called

graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...

. The canyons cut the cratered terrain, which means that they were formed at a relatively late stage of the moon's evolution, when the interior of Ariel expanded and its ice crust cracked as a result. The floor of the canyons is not visible on the images obtained by the ''

Voyager 2 ''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, ''Voyager 1'', on a ...

'' spacecraft in January 1986; thus, whether it is covered by smooth plains like the floors of other Arielian graben is currently unknown. During the ''Voyager 2'' flyby in 1986 the northern hemisphere of Ariel was not illuminated by the Sun because the spacecraft arrived during a southern

solstice A solstice is an event that occurs when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around June 21 and December 21. In many countr ...

on Uranus. Nevertheless, because it was still illuminated by light reflected from Uranus, scientists using advanced processing methods were able to detect some details in the dark hemisphere. These analyses revealed a continuation of the Kachina Chasmata into the dark hemisphere, possibly as far as to the opposite limb. As the total length of the feature appears to be 1800–2200 km, it may be comparable to

Ithaca Chasma Ithaca Chasma is a valley (graben) of Saturn's moon Tethys, named after the island of Ithaca, in Greece. It is up to wide, deep and long, running approximately three-quarters of the way around Tethys' circumference, making it one of the long ...

on Tethys.

References

Citations Sources * * * * * * Ariel (moon) Surface features of Uranian moons {{crater-stub