News and Public Affairs
Los Alamos National Laboratory
Nancy Ambrosiano, (505) 667-0471
March 10, 2006
Cassini measures geysers of Saturn's moon Enceladus
LOS ALAMOS, N.M. -- Cassini data obtained during a close flyby of the
Saturn moon Enceladus support an observation that large amounts of water
are spewing into space from the tiny moon's surface. This water
originates near south polar "hot spots" on the moon, possible locations
for the development of primitive life in the solar system.
Announced by the Cassini Imaging Science Team in today's issue of
Science, the theory is bolstered by measurements from the Cassini Plasma
Spectrometer (CAPS), as reported in the same issue by a team led by
Robert Tokar of Los Alamos National Laboratory. CAPS was partly designed
and built at Los Alamos.
"During the July 14 close flyby we began getting signatures, far from
Enceladus, of water ejection. From the deflections we could measure of
the ionized gas in the magnetosphere, it was erupting at 100 kg per
second (220 lbs per second), and the data are consistent with
measurements from the spacecraft's other instruments. It is actual H20
molecules," said Tokar.
Enceladus is a small moon, but highly reflective due to the fresh layer
of snow and ice on its surface. Tokar suggests that the icy geysers at
the south pole, erupting from a series of cracks, are pumping a
continuous flow of water particles into the area above the moon. Much of
the material falls back to the surface as snow.
In addition to constantly refreshing the snowy moon's surface, the
geysers also appear to be supplying oxygen atoms to the planet's E ring.
Like an icy version of a steam engine, the little moon is chugging
around its parent planet, leaving a floating trail visible to the
spacecraft's cameras and strong telescopes.
"Our paper, with 12 coauthors from US and Europe, looks at the plasma of
hydrogen, water and electrons in the ionized gas of the magnetosphere.
The magnetosphere itself deflects in the vicinity of Enceladus, and we
measure the plasma and that deflection. That is how we were able to
determine the amount of water being ejected," said Tokar.
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency and is run by NASA's
Jet Propulsion Laboratory. The principal investigator of the
multi-national CAPS team is David Young of Southwest Research Institute.
Images of Enceladus and Saturn are available at
Los Alamos National Laboratory is operated by the University of
California for the National Nuclear Security Administration of the U.S.
Department of Energy and works in partnership with NNSA's Sandia and
Lawrence Livermore national laboratories to support NNSA in its mission.
Los Alamos enhances global security by ensuring the safety and
reliability of the U.S. nuclear deterrent, developing technologies to
reduce threats from weapons of mass destruction, and solving problems
related to defense, energy, environment, infrastructure, health and
national security concerns.