Chaos terrain

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Conamara Chaos on Europa

In astrogeology, chaos terrain (or chaotic terrain) is a planetary surface area where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planet Mars, Mercury and Jupiter's moon Europa. In scientific nomenclature, "chaos" is used as a component of proper nouns (e.g., "Aureum Chaos" on Mars).[1]

On Mars[edit]

Main article: Martian chaos terrain

On April 1, 2010, NASA released the first images under the HiWish program in which just plain folk suggested places for HiRISE to photograph. One of the eight locations was Aureum Chaos.[2] The first image below gives a wide view of the area. The next two images are from the HiRISE image.[3]

On Mercury[edit]

Causes[edit]

The specific causes of chaos terrain are not yet well understood. A number of different astrogeological forces have been offered as causes of chaos terrain. On Europa, impact events and subsequent penetration into a ductile or liquid crust were suggested in 2004.[4] In November 2011, a team of researchers from the University of Texas at Austin and elsewhere presented evidence in the journal Nature suggesting that many "chaos terrain" features on Europa sit atop vast lakes of liquid water.[5] These lakes would be entirely encased in the moon's icy outer shell and distinct from a liquid ocean thought to exist farther down beneath the ice shell. Rather than an external impact, the authors propose a four step model for producing the surface expressions (chaos terrain) and the shallow, covered lakes. Full confirmation of the lakes' existence will require a space mission designed to probe the ice shell either physically or indirectly, for example using radar.

On Mars chaos terrain is believed to be associated with the release of huge amounts of water. The Chaotic features may have collapsed when water came out of the surface. Martian rivers begin with a Chaos region. A chaotic region can be recognized by a rat's nest of mesas, buttes, and hills, chopped through with valleys which in places look almost patterned. Some parts of this chaotic area have not collapsed completely—they are still formed into large mesas, so they may still contain water ice.[6] Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground. Chaos regions formed long ago. By counting craters (more craters in any given area means an older surface) and by studying the valleys' relations with other geological features, scientists have concluded the channels formed 2.0 to 3.8 billion years ago.[7]

In popular culture[edit]

  • In the graphic novel Watchmen, Dr. Manhattan ponders upon the alternative viewpoints of existence, and says that Mars did not choose life, but rather "chaotic terrain".

See also[edit]

References[edit]

  1. ^ Robert Roy Britt, "Chaos on Mars," Space.com
  2. ^ http://uahirise.org/releases/hiwish-captions.php
  3. ^ http://hirise.lpl.arizona.edu/ESP_016869_1775
  4. ^ Ong, Lissa. "Evidence that chaos terrain on Jupiter's moon Europa is formed by crust-penetrating impacts", Geological Society of America Abstracts with Programs, Vol. 36, No. 5, p. 144
  5. ^ Schmidt, Britney; Blankenship, Don; Patterson, Wes; Schenk, Paul (November 24, 2011). "Active formation of ‘chaos terrain’ over shallow subsurface water on Europa". Nature 479: 502–505. Bibcode:2011Natur.479..502S. doi:10.1038/nature10608. PMID 22089135. 
  6. ^ http://themis.asu.edu/features/aramchaos
  7. ^ http://themis.asu.edu/features/hydraotes

External links[edit]