Europa’s broken-ice puzzle
Processed image. Conamara Chaos combines a February 1997 background with five finer Galileo views from 16 December 1997. The inserted views show disrupted blocks at different scales; they are not a single simultaneous exposure or a film of ice moving. Published on 21 May 1998. This northern region is separate from the southern Thera/Thrace comparison.
NASA/JPL image-use policy · credited mission imagery, resized to WebP
· Original image source · Image licenceBlocks, bands and disrupted terrain on an icy world.
- World
- Europa
- Case date or period
- Observations · 1997–1998
Look closer
Galileo’s images of chaos terrain show broken-looking pieces embedded in a differently textured surface. The wider mosaic helps connect individual blocks with their surrounding geology.
Follow the evidence
Compare Conamara’s disrupted blocks with the separate southern regions Thera and Thrace. Their different apparent heights and textures help test competing formation histories. These photographic products combine dates, resolutions or colour filters; none films ice moving or directly reveals liquid below the crust. The investigation sections connect the visible terrain to model predictions and independent thermal constraints.
Broken ice constrains a subsurface model
Britney Schmidt and colleagues’ 2011 analysis combined Galileo topography and block relationships with terrestrial ice–water processes. Their model forms chaos terrain above shallow water lenses within a thick ice shell: melting, collapse, disruption and refreezing can produce the contrasting textures. Thera Macula supplied evidence for an incompletely disrupted, sunken region. These are interpretations of particular terrains, not a camera looking into a lake or proof that every patch of broken ice has liquid beneath it today.
A proposed active lake must pass a thermal test
Oleg Abramov and colleagues modelled the heat signature expected if Thera Macula were actively resurfacing. Their 2013 study compared that prediction with low-resolution Galileo temperatures, which were substantially colder. Insulating material, activity confined to small areas, or a cooling region could reconcile the difference; buried liquid might persist after surface activity ceased. The result qualifies the active-formation interpretation without establishing a unique history. Photographed blocks and thermal constraints must be assessed together.
Sources & further reading
- A Closer Look at Chaos on Europa — NASA Image and Video Library / JPL
- Regional Mosaic of Chaos and Gray Band on Europa — NASA Image and Video Library / JPL
- Chaos Transition — NASA Image and Video Library / JPL
- Active formation of chaos terrain over shallow subsurface water on Europa — Schmidt and colleagues (2011) — Nature / scholarly repository copy, Woods Hole Oceanographic Institution
- Detectability of thermal signatures associated with active formation of chaos terrain on Europa — Abramov and colleagues (2013) — USGS / Earth and Planetary Science Letters research abstract
- Thera and Thrace on Europa — Galileo photographic mosaic — NASA / JPL / University of Arizona