Europa is the smallest of the Galilean moons, behind Io, Callisto, and Ganymede, and is one of the satellites belonging to Jupiter. This moon was found by Galileo Galilei and the less credited, Simon Marius, on January 8, 1610, the day after Ganymede, the largest of Jupiter's natural satellites, was discovered.[1] It is the sixth largest moon in the solar system. Europa is the smoothest known object in the Solar System, lacking large-scale features such as mountains and craters. However, according to one study, Europa's equator may be covered in icy spikes called penitentes, which may be up to 15 meters high, due to direct overhead sunlight on the equator, causing the ice to sublime, forming vertical cracks.
Formation
Europa and the other Galilean moons formed from a debris disc around Jupiter, most of the moons spiralled into the Jupiter leaving only Io, Europa, Ganymede, and Callisto.
Composition
A hypothesis for the colored regions is that they are composed of abiotic organic compounds collectively called tholins. The morphology of Europa's impact craters and ridges is suggestive of fluidized material welling up from the fractures where pyrolysis and radiolysis take place. In order to generate colored tholins on Europa there must be a source of materials (carbon, nitrogen, and water) and a source of energy to make the reactions occur. Impurities in the water ice crust of Europa are presumed both to emerge from the interior as cryovolcanic events that resurface the body, and to accumulate from space as interplanetary dust. Tholins bring important astrobiological implications, as they may play a role in prebiotic chemistry and abiogenesis.
Subterranean Ocean
Europa contains an ocean deep inside of the moon, just like Ganymede or perhaps Callisto. Tidal flexing[2], which is flexing caused by gravitational pulls between surrounding moons, keeps the ocean liquefied. It is possible there is life in it.[3]
Gallery
| Geology of Europa | |
|---|---|
| Craters | Áine • Cilix • Pwyll |
| Lineae | Adonis • Agave • Agenor • Alphesiboea • Androgeos • Argiope • Asterius • Astypalaea • Autonoë • Belus • Butterdon • Cadmus • Chthonius • Corick • Drizzlecomb • Drumskinny • Echion • Euphemus • Glaukos • Harmonia • Hyperenor • Ino • Katreus • Kennet • Libya • Mehen • Merrivale • Minos • Onga • Pelagon • Pelorus • Phineus • Phoenix • Rhadamanthys • Sarpedon • Sharpitor • Sparti • Staldon • Tectamus • Telephassa • Thasus • Thynia • Tormsdale • Udaeus • Yelland |
| Chaotic Terrain | Arran • Conamara • Murias • Narberth • Rathmore |
| Regions | Annwn • Argadnel • Balgatan • Dyfed • Falga • Moytura • Powys • Tara |
| Flexus | Cilicia • Delphi • Gortyna • Phocis • Sidon |
| Fossae | Beenalaght • Eightercua • Kerlescan • Kermario • Maughanasilly • Ménec |
| Mensa | Belenos Mensa • Borvo Mensa • Grannus Mensa |
| Maculae | Boeotia • Castalia • Cyclades • Thera • Thrace |
| Cavi | Moyle Cavus |
| Large ringed features | Callanish • Tyre |