Chaos terrain is an astrogeological term used to denote planetary surface areas 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

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

 and Jupiter

Jupiter

Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

's moon Europa

Europa (moon)

Europa Slightly smaller than Earth's Moon, Europa is primarily made of silicate rock and probably has an iron core. It has a tenuous atmosphere composed primarily of oxygen. Its surface is composed of ice and is one of the smoothest in the Solar System. This surface is striated by cracks and...

. In scientific nomenclature, "chaos" is used as a component of proper nouns (e.g., "Aureum Chaos

Aureum Chaos

Aureum Chaos is a rough, collapsed region in the Margaritifer Sinus quadrangle of Mars at4.4° south latitude and 27° west longitude. It is 368 km across and was named after a classical albedo feature name...

" on Mars).

Main article: Martian chaos terrain

Martian chaos terrain

- Chaos terrain on Mars :Chaos terrain on Mars is distinctive; nothing on Earth compares to it. Chaos terrain generally consists of irregular groups of large blocks, some tens of kilometres across and a hundred or more meters high. The tilted and flat topped blocks form depressions hundreds of...

On April 1, 2010, NASA released the first images under the HiWish program

HiWish program

HiWish is a program created by NASA the so that anyone can suggest a place for the HiRISE camera on the Mars Reconnaissance Orbiter to photograph. It was started in January 2010. The first images were released in April 2010...

 in which just plain folk suggested places for HiRISE to photograph. One of the eight locations was Aureum Chaos. The first image below gives a wide view of the area. The next two images are from the HiRISE image.

Causes

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 have been suggested.

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. 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.

In popular culture

• In the graphic novel Watchmen
  Watchmen
  Watchmen is a twelve-issue comic book limited series created by writer Alan Moore, artist Dave Gibbons, and colourist John Higgins. The series was published by DC Comics during 1986 and 1987, and has been subsequently reprinted in collected form...
  
  , Dr. Manhattan ponders upon the alternative viewpoints of existence, and says that Mars
  Mars
  Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
  
   did not choose life, but rather "chaotic terrain".

See also

• Arachnoids
  Arachnoid (astrogeology)
  In astrogeology, an arachnoid is a large structure of unknown origin, and they have been found only on the surface of the planet Venus. Arachnoids get their name from their resemblance to spider webs. They appear as concentric ovals surrounded by a complex network of fractures, and can span 200...
  
  
• Areas of chaos terrain on Mars
  Areas of chaos terrain on Mars
  This is a list of areas of chaos terrain officially named by the International Astronomical Union on the planet Mars. Chaos terrain is an astrogeological term used to denote planetary surface areas where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another...
  
  
• Astrogeology
• Martian spiders
• Rilles