Europa:
Icy Rock or Dynamic World?
By Michael Wright
Abstract
Recent exploration of our solar system has
produced an array of data about the planets and their moons. Jupiter’s Galilean moons have been the focus
of a great deal of this exploration. In
1979 Voyagers 1 and 2 made a fly by of Europa and
returned a number of photographs that showed a smooth surface with little to
know substantial features. From this
early time researchers believed that Europa was
covered by a layer of ice which potentially covered a liquid water ocean. In December of 1995 the Galileo spacecraft
reached Jupiter. For eight years the
craft orbited the gas giant and returned extensive data about Europa. Data from
photographs, magnetometers, and mathematical modeling lend support to the
hypothesis of a liquid water ocean beneath the thick crust of Jupiter’s second
moon
Nielsen & Linnet (2003) from
http://mac18.anthro.ku.dk/~sivert/courses/2003-1_Europa/bilder3.htm
Cracks and Ridges
on the surface of Europa
NASA
(2004) from http://www2.worldbook.com/features/jupiter/assets/europa1.jpg
Triple Bands caused
by the upwelling of material and the spreading of plates on Europa
NASA/JPL/DLR
from http://geologyindy.byu.edu/ePlanet/images/Ch%209/Europa-fig.-9.19.jpg
(a) (b) (c)
Surface features on
Europa illustrating Cracks and Ridges, Chaos Terrain
and one of the few large impact craters. The lack of significant surface relief
and large craters of other moons implies a young surface.
(a)
http://atropos.as.arizona.edu/aiz/teaching/nats102/images/Europa_surface.gif
(b)
NASA JPL from http://jcboulay.free.fr/astro/sommaire/astronomie/univers/galaxie/etoile/systeme_solaire
/jupiter/europe/europa_imp_gal1.jpg
c) NASA
JPL from http://brattahlid.tripod.com/sw3-65webb.htm
Surface photo of
the Earth’s moon for comparison with Europa’s surface
features. Note the intense cratering normally
associated with moons throughout the solar system.
From
http://www.digitecoptical.com/images/moon-10-019sm.gif
Illustration of
possible convecting features deep within Europa’s interior.
NASA
from http://www.433eros.com/headlines/y2001/4review_europa_sonar.htm
Proposed
internal structure for Europa.
From
http://www.admiroutes.asso.fr/action/theme/science/actu/2000/galcoup.jpg
References
Greenberg, R.
(2002). Tides and the biosphere of Europa: A
liquid-water ocean beneath a thin crust of ice may offer several habitats for
the evolution of life on one of Jupiter’s moons. American
Scientist Jan-Feb v90 i1; 48-56.
Nimmo, F., Pappalardo,
R.T., and Giese, B. (2003).
On the origins of band topogaphy, Europa. Icarus 166;
21-32.
Stevenson, D.
(2000). Europa’s Ocean-the case strengthens. Science August 25, v289; 1305-1307.