As Saturn's active moon Enceladus continues to spew icy particles into
space, scientists struggle to understand the mechanics of what is going
on beneath the fractured south polar terrain. This graphic illustrates
key aspects of the model proposed by the Cassini imaging science team in
a paper published in the journal Science on March 10, 2006.
The model shows how proposed underground reservoirs of pressurized liquid
water above 273 degrees Kelvin (0 degrees Celsius) could fuel geysers that
send jets of icy material into the skies above the moon's south pole. In
the graphic, the vent to the surface pierces one of the "tiger stripe"
fractures seen in Cassini views of the southern polar terrain (see PIA06247
for a look at the tiger stripes). Temperatures increase with depth.
Some combination of internal radioactive decay and flexing -- perhaps
concentrated within the tiger stripe fractures and brought about by the
particular characteristics of Enceladus' orbit--is implicated as the
source of the heat creating the liquid reservoirs. However, it is not yet
clear how the deep interior of Enceladus functions, nor whether the moon
is fully differentiated (separated into layers, with rock at the center
and ice outside).
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages
the mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter and its two onboard cameras were designed, developed and
assembled at JPL. The imaging operations center is based at the Space
Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/home/index.cfm. The Cassini imaging team
homepage is at http://ciclops.org.
