Pwyll (crater)
Encyclopedia
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
Pwyll (named after the Pwyll
Pwyll
Pwyll Pen Annwn is a prominent figure in Welsh mythology and literature, the lord of Dyfed, husband of Rhiannon and father of the hero Pryderi...
of Welsh mythology
Welsh mythology
Welsh mythology, the remnants of the mythology of the pre-Christian Britons, has come down to us in much altered form in medieval Welsh manuscripts such as the Red Book of Hergest, the White Book of Rhydderch, the Book of Aneirin and the Book of Taliesin....
) is thought to represent one of the youngest features on the surface of 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
Natural satellite
A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
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...
.
Pwyll's visible dark central region is about 26 kilometers in diameter, while brilliant white rays of debris blasted from the impact site extend outward for hundreds of kilometers. The white debris or ejecta clearly overlays everything else on the surface - indicating that this impact crater is younger than all surrounding features. The bright white color suggests a composition of water ice particles. Galileo's instruments have uncovered substantial evidence that water in liquid form exists below Europa's icy surface. If Europa has a subsurface ocean, it might also contain life.