Cruising past the moons [
http://www.jpl.nasa…] of reigning gas giant Jupiter, Voyager [
http://vraptor.jpl.…] and Galileo [
http://www.jpl.nasa…] have returned tantalizing evidence for a liquid water ocean beneath the surface of Europa [
http://antwrp.gsfc.…]. Now researchers are reporting [
http://www.jpl.nasa…] telltale indications that the battered Jovian moon Callisto [
http://antwrp.gsfc.…] may also harbor a subsurface ocean. This cutaway view [
http://photojournal…cgi-bin/PIAGenCatalo gPage.pl?PIA01478 ] of Callisto shows a whitish 200 kilometer thick band of ice just beneath the moon's surface. The hypothetical ocean - indicated by the underlying light blue stripe - is potentially a salty layer of liquid water up to 10 kilometers thick, while the rest of the interior is seen as a jumble of rock and ice. Why a salty subsurface ocean? Magnetic measurements made [
http://www.jpl.nasa…] during Galileo flybys so far indicate Callisto's magnetic field is variable, analogous to results during Europa passes [
http://www.jpl.nasa…], and a plausible explanation is that Callisto [
http://www.jpl.nasa…] too has a subsurface liquid layer. If the liquid were salt water it could easily carry electrical currents [ http://image.gsfc.na sa.gov/poetry//storm 0/black3.html ] and produce the changing magnetic field [ http://image.gsfc.na sa.gov/poetry//magla b/maglab.html ].
Explanation
Cruising past the moons [
http://www.jpl.nasa…] of reigning gas giant Jupiter, Voyager [
http://vraptor.jpl.…] and Galileo [
http://www.jpl.nasa…] have returned tantalizing evidence for a liquid water ocean beneath the surface of Europa [
http://antwrp.gsfc.…]. Now researchers are reporting [
http://www.jpl.nasa…] telltale indications that the battered Jovian moon Callisto [
http://antwrp.gsfc.…] may also harbor a subsurface ocean. This cutaway view [
http://photojournal…cgi-bin/PIAGenCatalo gPage.pl?PIA01478 ] of Callisto shows a whitish 200 kilometer thick band of ice just beneath the moon's surface. The hypothetical ocean - indicated by the underlying light blue stripe - is potentially a salty layer of liquid water up to 10 kilometers thick, while the rest of the interior is seen as a jumble of rock and ice. Why a salty subsurface ocean? Magnetic measurements made [
http://www.jpl.nasa…] during Galileo flybys so far indicate Callisto's magnetic field is variable, analogous to results during Europa passes [
http://www.jpl.nasa…], and a plausible explanation is that Callisto [
http://www.jpl.nasa…] too has a subsurface liquid layer. If the liquid were salt water it could easily carry electrical currents [ http://image.gsfc.na sa.gov/poetry//storm 0/black3.html ] and produce the changing magnetic field [ http://image.gsfc.na sa.gov/poetry//magla b/maglab.html ].
Explanation
