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

 

Anderson, J.D., Schubert, G., Jacobson, R.A., Lau, E.L., Moore, W.B., and Sjogren, W.L. (1998). Europa’s differentiated internal structure: inferences from four Galileo encounters. Science September 25, v281 n5385; 2019-2023.

 

Chandler, D.L. and Hecht, J. (2002). Cracking Europa’s icy mask: distant moons loom large, as astronomers pierce ice and gas to find strange new worlds—and perhaps even life. New Scientist October 19, v176 i2365; 24-25.

 

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.