The Kachina Chasmata are the longest known

canyon A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency t ...

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 *, a Russian film directed by Yevgeni Kotov * ''ARIEL Visual'' and ''ARIEL Deluxe'', a 1989 and 1991 ...

. The name comes from

kachina A kachina (; Hopi language, Hopi: ''katsina'' , plural ''katsinim'' ) is a spirit being in the religious beliefs of the Pueblo people, Native Americans in the United States, Native American cultures located in the south-western part of the Unite ...

, a spirit in

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 i ...

. 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 the south-east. The faults bound down-dropped crustal blocks forming structures called

graben In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...

. 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, as a part of the Voyager program. It was launched on a trajectory towards the gas giants (Jupiter and Saturn) and enabled further encounters with the ice giants (Uranus and ...

'' 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 the time when the Sun reaches its most northerly or southerly sun path, excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around 20–22 June and 20–22 December. In many countries ...

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 the opposite limb. As the total length of the feature appears to be 1800–2200 km, it may be comparable to Ithaca Chasma on Tethys.

References

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