Organic Matter Found in
Saturn Moon's Geysers
As
reported by NASA & FOX News
NASA
Mission News
Cassini Tastes Organic Material at Saturn's Geyser Moon
03.26.08
.jpg)
PASADENA,
Calif. -- NASA's Cassini spacecraft tasted and sampled a surprising organic brew
erupting in geyser-like fashion from Saturn's moon Enceladus during a close
flyby on March 12. Scientists are amazed that this tiny moon is so active, "hot"
and brimming with water vapor and organic chemicals.
New heat maps of the surface show higher temperatures than previously known in
the south polar region, with hot tracks running the length of giant fissures.
Additionally, scientists say the organics "taste and smell" like some of those
found in a comet. The jets themselves harmlessly peppered Cassini, exerting
measurable torque on the spacecraft, and providing an indirect measure of the
plume density.
"A completely unexpected surprise is that the chemistry of Enceladus, what's
coming out from inside, resembles that of a comet," said Hunter Waite, principal
investigator for the Cassini Ion and Neutral Mass Spectrometer at the Southwest
Research Institute in San Antonio. "To have primordial material coming out from
inside a Saturn moon raises many questions on the formation of the Saturn
system."
"Enceladus is by no means a comet. Comets have tails and orbit the sun, and
Enceladus' activity is powered by internal heat while comet activity is powered
by sunlight. Enceladus' brew is like carbonated water with an essence of natural
gas," said Waite.
The Ion and Neutral Mass Spectrometer saw a much higher density of volatile
gases, water vapor, carbon dioxide and carbon monoxide, as well as organic
materials, some 20 times denser than expected. This dramatic increase in density
was evident as the spacecraft flew over the area of the plumes.
.jpg)
New
high-resolution heat maps of the south pole by Cassini's Composite Infrared
Spectrometer show that the so-called tiger stripes, giant fissures that are the
source of the geysers, are warm along almost their entire lengths, and reveal
other warm fissures nearby. These more precise new measurements reveal
temperatures of at least minus 93 degrees Celsius (minus 135 Fahrenheit.) That
is 35 degrees Celsius (63 degrees Fahrenheit) warmer than previously seen and
115 degrees Celsius (207 degrees Fahrenheit) warmer than other regions of the
moon. The warmest regions along the tiger stripes correspond to two of the jet
locations seen in Cassini images.
"These spectacular new data will really help us understand what powers the
geysers. The surprisingly high temperatures make it more likely that there's
liquid water not far below the surface," said John Spencer, Cassini scientist on
the Composite Infrared Spectrometer team at the Southwest Research Institute in
Boulder, Colo.
Previous ultraviolet observations showed four jet sources, matching the
locations of the plumes seen in previous images. This indicates that gas in the
plume blasts off the surface into space, blending to form the larger plume.
Images from previous observations show individual jets and mark places from
which they emanate. New images show how hot spot fractures are related to other
surface features. In future imaging observations, scientists hope to see
individual plume sources and investigate differences among fractures.
"Enceladus has got warmth, water and organic chemicals, some of the essential
building blocks needed for life," said Dennis Matson, Cassini project scientist
at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We have quite a recipe
for life on our hands, but we have yet to find the final ingredient, liquid
water, but Enceladus is only whetting our appetites for more."
At closest approach, Cassini was only 30 miles from Enceladus. When it flew
through the plumes it was 120 miles from the moon's surface. Cassini's next
flyby of Enceladus is in August.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space
Agency and the Italian Space Agency. The mission is managed by JPL for NASA's
Science Mission Directorate, Washington.
For images and more information, visit
http://www.nasa.gov/cassini and
http://saturn.jpl.nasa.gov .
Media contacts:
Carolina Martinez 818-354-9382
Jet Propulsion Laboratory, Pasadena, Calif.
carolina.martinez@jpl.nasa.gov
Dwayne Brown 202-358-2726
NASA Headquarters,
Washington
dwayne.c.brown@nasa.gov
2008-050
Jet Spots in Tiger
Stripes
03.26.08
.jpg)
Heat radiating from the entire length of 150 kilometer (95 mile)-long fractures
is seen in this best-yet heat map of the active south polar region of Saturn's
ice moon Enceladus. The warmest parts of the fractures tend to lie on locations
of the plume jets identified in earlier images, shown in the annotated version
with yellow stars. The measurements were obtained by the Cassini spacecraft's
Composite Infrared Spectrometer from the spacecraft's close flyby of the moon on March 12, 2008.
Remarkably high temperatures, at least 180 Kelvin (minus 135 degrees Fahrenheit)
were registered along the brightest fracture, named Damascus Sulcus, in the
lower left portion of the image. For comparison, surface temperatures elsewhere
in the south polar region of Enceladus are below 72 Kelvin (minus 330 degrees
Fahrenheit).
Heat is escaping from Enceladus' interior along these warm fractures, dubbed
"tiger stripes," which are also the source of the geysers that erupt from the
polar region. The infrared radiation was mapped at wavelengths between 12 and 16
microns. The infrared data, shown in false color, are superimposed on a
grayscale image mosaic of the south pole obtained by Cassini's cameras on July 14, 2005, during the
previous close Enceladus flyby. Numbers on the map indicate latitude and
longitude.
This new view shows that at least three of the south polar fractures are active
along almost their full lengths--the fourth one, on the right, was only
partially covered by this scan. The level of activity varies greatly along the
fractures. The warmest parts of the fractures tend to lie on locations of the
plume jets identified in earlier images. The main "tiger stripe" fractures are
not the only sources of heat, however; additional warm spots are seen in the
upper right part of the scan. The warm regions are probably concentrated within
less than a few hundred meters (a few hundred yards) of the fractures, and their
apparent width in this image results from the relatively low resolution of the
infrared data.
This map was made by scanning the south pole during the period from 16 to 37
minutes after closest approach to Enceladus, at a distance between 14,000 and
32,000 kilometers (about 8,700 and 20,000 miles) as Cassini rapidly receded from
its close (50-kilometer or 32-mile) flyby.
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 was
designed, developed and assembled at JPL. The composite infrared spectrometer
team is based at NASA's Goddard Space Flight Center,
Greenbelt, Md.
For more information about the Cassini-Huygens mission visit
http://ciclops.org . Credit:
NASA/JPL/Space Science Institute
Stellar Data on Plume
03.26.08
.jpg)
New structure, density and composition measurements of Enceladus' water plume
were obtained when the Cassini spacecraft's Ultraviolet Imaging Spectrograph
observed the star zeta Orionis pass behind the plume Oct. 24, 2007, as seen in this
animation.
Changes in the starlight as it dimmed while passing through the plume allowed
the spectrograph to identify the plume's physical and chemical composition. The
spectrograph detected four high-density gas streams composed of water vapor. The
density of the water vapor is twice that of the broad plume of gas that
surrounds each jet.
This measurement confirms the theoretical analysis performed prior to the flyby
that showed it was safe for Cassini to fly very closely past Enceladus, even
through part of the plume, during the March 12, 2008 flyby.
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 was
designed, developed and assembled at JPL. The ultraviolet imaging spectrograph
was designed and built at, and the team is based at, the University of Colorado,
Boulder.
For more information about
the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov.
Credit: NASA/JPL/University
of Colorado/SSI
FOX News
http://www.foxnews.com/story/0,2933,343012,00.html?sPage=fnc/scitech/space
