%0 Journal Article %1 Carr1998 %A Carr, M. H. %A Belton, M. J. S. %A Chapman, C. R. %A Davies, A. S. %A Geissler, P. %A Greenberg, R. %A McEwen, A. S. %A Tufts, B. R. %A Greeley, R. %A Sullivan, R. %A Head, J. W. %A Pappalardo, R. T. %A Klaasen, K. P. %A Johnson, T. V. %A Kaufman, J. %A Senske, D. %A Moore, J. %A Neukum, G. %A Schubert, G. %A Burns, J. A. %A Thomas, P. %A Veverka, J. %D 1998 %J Nature %K imported %N 6665 %P 363--365 %T Evidence for a subsurface ocean on Europa %V 391 %X Ground-based spectroscopy of Jupiter's moon Europa, combined with gravity data, suggests that the satellite has an icy crust roughly 150 km thick and a rocky interior(1-4). In addition, images obtained by the voyager spacecraft revealed that Europa's surface is crossed by numerous intersecting ridges and dark bands (called lineae) and is sparsely cratered, indicating that the terrain is probably significantly younger than that of Ganymede and Callisto(5). It has been suggested that Europa's thin outer ice shell might be separated from the moon's silicate interior by a liquid water layer, delayed or prevented from freezing by tidal heating(6-10); in this model, the lineae could be explained by repetitive tidal deformation of the outer ice shell(11-13). However, observational confirmation of a subsurface ocean was largely frustrated by the low resolution (>2 km per pixel) of the Voyager images(14). Here we present high-resolution (54 m per pixel) Galileo spacecraft images of Europa, in which we find evidence for mobile 'icebergs'. The detailed morphology of the terrain strongly supports the presence of liquid water at shallow depths below the surface, either today or at some time in the past. Moreover, lower-resolution observations of much larger regions suggest that the phenomena reported here are widespread.

@article{Carr1998, abstract = {Ground-based spectroscopy of Jupiter's moon Europa, combined with gravity data, suggests that the satellite has an icy crust roughly 150 km thick and a rocky interior(1-4). In addition, images obtained by the voyager spacecraft revealed that Europa's surface is crossed by numerous intersecting ridges and dark bands (called lineae) and is sparsely cratered, indicating that the terrain is probably significantly younger than that of Ganymede and Callisto(5). It has been suggested that Europa's thin outer ice shell might be separated from the moon's silicate interior by a liquid water layer, delayed or prevented from freezing by tidal heating(6-10); in this model, the lineae could be explained by repetitive tidal deformation of the outer ice shell(11-13). However, observational confirmation of a subsurface ocean was largely frustrated by the low resolution (>2 km per pixel) of the Voyager images(14). Here we present high-resolution (54 m per pixel) Galileo spacecraft images of Europa, in which we find evidence for mobile 'icebergs'. The detailed morphology of the terrain strongly supports the presence of liquid water at shallow depths below the surface, either today or at some time in the past. Moreover, lower-resolution observations of much larger regions suggest that the phenomena reported here are widespread.}, added-at = {2009-11-03T20:21:25.000+0100}, author = {Carr, M. H. and Belton, M. J. S. and Chapman, C. R. and Davies, A. S. and Geissler, P. and Greenberg, R. and McEwen, A. S. and Tufts, B. R. and Greeley, R. and Sullivan, R. and Head, J. W. and Pappalardo, R. T. and Klaasen, K. P. and Johnson, T. V. and Kaufman, J. and Senske, D. and Moore, J. and Neukum, G. and Schubert, G. and Burns, J. A. and Thomas, P. and Veverka, J.}, biburl = {https://www.bibsonomy.org/bibtex/2b4f0fac9640b56767bd4950edceb3f30/svance}, citedreferences = {ANDERSON JD, 1997, Science, V276, P1236 ; Cassen P, 1979, GEOPHYS RES LETT, V6, P731 ; Cassen P, 1980, GEOPHYS RES LETT, V7, P987 ; CHAPMAN C, 1997, LUNAR PLANET SCI C, V28, P217 ; Greeley R, UNPUB ; Greenberg R, 1984, Icarus, V58, P186 ; HELFENSTEIN P, 1985, Icarus, V61, P175 ; KUIPER GP, 1961, PLANETS SATELLITES ; LUCCHITTA BK, 1982, SATELLITES JUPITER, P521 ; MCEWEN AS, 1986, Nature, V321, P49 ; MOROZ VI, OSV ASTRON A J, V9, P999 ; MORRISON D, 1974, SPACE SCI REV, V15, P641 ; Ojakangas GW, 1989, Icarus, V81, P220 ; PAPPALARDO RT, 1996, Icarus, V123, P557 ; PAPPALARDO RT, 1996, LUNAR PLANET SCI C, V27, P997 ; PAPPALARDO RT, 1996, P EUR OC C, P59 ; PAPPALARDO RT, 1998, Nature, V391, P365 ; ROSS M, 1986, Nature, V325, P13 ; SCHENK PM, 1989, Icarus, V79, P75 ; SHOEMAKER EM, 1996, P EUR OC C, P65 ; SMITH BA, 1979, Science, V206, P927 ; Squyres SW, 1983, Nature, V301, P225 ; SULLIVAN R, 1997, LUNAR PLANET SCI, V28, P1395 ; TUFTS RB, 1997, LUNAR PLANET SCI C, V28, P1455}, interhash = {d2680f8b1f0976bf9a10e683dedb12ab}, intrahash = {b4f0fac9640b56767bd4950edceb3f30}, journal = {Nature}, keywords = {imported}, number = 6665, owner = {svance}, pages = {363--365}, timestamp = {2009-11-03T20:21:42.000+0100}, title = {Evidence for a subsurface ocean on Europa}, volume = 391, year = 1998 }