|
Posted by baalke on October 10, 2007, 5:03 pm
Please log in for more thread options
Contact:
Preston Dyches
1-720-974-5859
media@ciclops.org
Oct. 10, 2007
CASSINI PINPOINTS HOT SOURCES OF JETS ON ENCELADUS
A recent analysis of images from NASA's Cassini spacecraft provides
conclusive evidence that the jets of fine, icy particles spraying from
Saturn's moon Enceladus originate from the hottest spots on the moon's
"tiger stripe" fractures that straddle the moon's south polar region.
Members of Cassini's imaging team used two years' worth of pictures of
the geologically active moon to locate the sources of the most
prominent
jets spouting from the moon's surface. They then compared these
surface
source locations to hot spots detected by Cassini on Enceladus in
2005.
The new results are published in the Oct. 11, 2007, issue of the
journal
Nature.
The researchers found that all of the jets appear to come from the
four
prominent tiger stripe fractures in the moon's active south polar
region
and, in almost every case, in the hottest areas detected by Cassini's
composite and infrared spectrometer.
"This is the first time the visible jets have been tied directly to
the
tiger stripes," said Joseph Spitale, an imaging team associate and
lead
author of the Nature paper. Spitale works with Cassini imaging team
leader and co-author Carolyn Porco, at the Space Science Institute in
Boulder, Colo.
Imaging scientists suspected the individual jets, which collectively
feed a plume that towers thousands of kilometers, or miles, above the
moon, had been coming from the tiger stripes since the first images of
the jets were taken in 2005. But this work provides the first
conclusive
proof of that hypothesis and provides the first direct evidence of a
causal connection between the jets and the unusual heat radiating from
the fractures.
To identify the jets' surface locations with certainty, the
researchers
carefully measured the apparent position and orientation of each jet
as
observed along the moon's edge by the spacecraft. By making
measurements
taken from a variety of viewing directions, they were able to pinpoint
the jets' sources.
What Spitale and Porco found was intriguing: all measured jets fell on
a
fracture, but not all jets fell on a previously discovered hot spot.
They conclude there are other hot spots to be found.
"Some of our sources occur in regions not yet observed by Cassini's
composite infrared spectrometer," said Spitale. "So we are predicting
that future Cassini observations of those locations will find elevated
temperatures."
The scientists also report the suggestion that the characteristics of
the jets may depend on tidal frictional heating within the fractures
and
its variation over a full Enceladus orbit around Saturn. However, more
work remains in investigating this issue.
The possibility, first suggested by the imaging team, that the jets
may
erupt from pockets of liquid water, together with the unusually warm
temperatures and the organic material detected by Cassini in the vapor
accompanying the icy particles, immediately shoved this small
Saturnian
moon into the spotlight as a potential solar system habitable zone.
But what actually lies beneath the surface to power the jets remains a
mystery.
"These are findings with tremendously exciting implications and to say
that I am eager to get to the bottom of it would be a cosmic
understatement," said Porco. "Do the jets derive from near-surface
liquid water or not? And if not, then how far down is the liquid water
that we all suspect resides within this moon? Personally, I'd like to
know the answer yesterday!"
The next opportunity for answering these questions will be when
Cassini
dips low over Enceladus and flies through the plume in March 2008,
obtaining additional data about its chemical composition and the
nature
of its jets.
A newly processed Cassini image of the jets, and a map of the south
polar region showing the correlations between jets and hot spots, can
be
found at http://ciclops.org, http://www.nasa.gov/cassini and
http://saturn.jpl.nasa.gov
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Jet Propulsion
Laboratory (JPL), a division of the California Institute of Technology
in Pasadena, manages the Cassini-Huygens mission for NASA's Science
Mission Directorate, Washington. The Cassini orbiter and its two
onboard
cameras were designed, developed and assembled at JPL. The imaging
team
consists of scientists from the U.S., England, France, and Germany.
The
imaging operations center and team leader (Dr. C. Porco) are based at
the Space Science Institute in Boulder, Colo.
|
| Similar Threads | Posted | | A possible origin for the jets of Enceladus. | January 15, 2006, 10:05 am |
| Cassini Confirms a Dynamic Atmosphere at Saturn's Moon Enceladus | July 29, 2005, 7:56 am |
| NASA's Cassini Discovers Potential Liquid Water on Enceladus | March 9, 2006, 2:34 pm |
| Cassini Findings Suggest Complex Story of Venting at the South Pole of Enceladus | August 30, 2005, 6:02 pm |
| Velikovsky/Neocatastrophism Sources | October 29, 2006, 6:55 pm |
| NASA Findings Suggest Jets Bursting From Martian Ice Cap | August 16, 2006, 8:14 pm |
| The Fountains of Enceladus | November 28, 2005, 5:24 pm |
| OT: Fountains of Enceladus | November 30, 2005, 2:27 pm |
| Enceladus Exudes an Air of Mystery | June 30, 2006, 2:07 pm |
| A Hot Start Might Explain Geysers on Enceladus | March 12, 2007, 11:39 am |
|
XML Sitemap