Chaos terrain

[1] On April 1, 2010, NASA released the first images under the HiWish program in which citizens suggested places for HiRISE to photograph.

An original theory for the formation of chaos terrain on Mercury is an impact basin on the opposite side of the planet.

Warm water plumes can melt the surface of Europa, and then movements of the shell can move chaos terrain to a different location than where it was formed.

[8] 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.

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.

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.

[10] Chaotic terrain occurs in numerous locations on Mars, and always gives the strong impression that something abruptly disturbed the ground.

If hot magma came near to the region, the ice would have melted and formed large underground river systems.

[12][13][14][15] Places have been photographed that could be where the ground collapsed when water left subterranean rivers to flow out of chaotic regions.

It was thought that these outflows came from a global cryosphere-confined aquifer that collected water from south polar meltwater.