Jets of icy particles burst from Saturn’s moon Enceladus in this
brief movie sequence of four images taken on Nov. 27, 2005. The
sensational discovery of active eruptions on a third outer solar system
body (Io and Triton are the others) is surely one of the great highlights
of the Cassini mission.
Imaging scientists, as reported in the journal Science on March 10,
2006, believe that the jets are geysers erupting from pressurized
subsurface reservoirs of liquid water above 273 degrees Kelvin (0
degrees Celsius).
Images taken in January 2005 appeared to show the plume emanating
from the fractured south polar region of Enceladus, but the visible plume
was only slightly brighter than the background noise in the image,
because the lighting geometry was not suitable to reveal the true details
of the feature. This potential sighting, in addition to the detection of the
icy particles in the plume by other Cassini instruments, prompted imaging
scientists to target Enceladus again with exposures designed to confirm
the validity of the earlier plume sighting.
The new views show individual jets, or plume sources, that contribute to
the plume with much greater visibility than the earlier images. The full plume
towers over the 505-kilometer-wide (314-mile) moon and is at least as tall as
the moon's diameter.
The four 10-second exposures were taken over the course of about 36
minutes at approximately 12 minute intervals.
Enceladus rotates about 7.5 degrees in longitude over the course of the
frames, and most of the observed changes in the appearances of the jets
is likely attributable to changes in the viewing geometry. However, some
of the changes may be due to actual variation in the flow from the jets on
a time scale of tens of minutes.
Additionally, the shift of the sources seen here should provide information
about their location in front of and behind the visible limb (edge) of Enceladus.
These images were obtained using the Cassini spacecraft narrow-angle
camera at distances between 144,350 and 149,520 kilometers (89,695
and 92,907 miles) from Enceladus and at a phase angle of about 161
degrees. Image scale is about 900 meters (2,950 feet) per pixel on Enceladus.
This caption was updated on March 9, 2006.
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. The Cassini imaging team homepage is at
http://ciclops.org.
