Radical! Liquid Water on Enceladus
2006 03 11
Fountains Discovered on Saturn's Enceladus. More. Image from: nasa.gov
NASA's Cassini spacecraft may have found evidence of liquid water reservoirs that erupt in Yellowstone-like geysers on Saturn's moon Enceladus. The rare occurrence of liquid water so near the surface raises many new questions about this mysterious moon.
"We realize that this is a radical conclusion -- that we may have evidence for liquid water within a body so small and so cold," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute, Boulder, Colo. "However, if we are right, we have significantly broadened the diversity of solar system environments where we might possibly have conditions suitable for living organisms."
High-resolution Cassini images show icy jets and towering plumes ejecting huge quantities of particles at high speed. Scientists examined several models to explain the process. They ruled out the idea the particles are produced or blown off the moon's surface by vapor created when warm water ice converts to a gas. Instead, scientists have found evidence for a much more exciting possibility. The jets might be erupting from near-surface pockets of liquid water above 0 degrees Celsius (32 degrees Fahrenheit), like cold versions of the Old Faithful geyser in Yellowstone: illustration.
"We previously knew of at most three places where active volcanism exists: Jupiter's moon Io, Earth, and possibly Neptune's moon Triton. Cassini changed all that, making Enceladus the latest member of this very exclusive club, and one of the most exciting places in the solar system," said John Spencer, Cassini scientist, Southwest Research Institute, Boulder.
"Other moons in the solar system [may] have liquid-water oceans covered by kilometers of icy crust," said Andrew Ingersoll, imaging team member and atmospheric scientist at the California Institute of Technology, Pasadena, Calif. "What's different here is that pockets of liquid water may be no more than tens of meters below the surface."
"As Cassini approached Saturn, we discovered the Saturnian system is filled with oxygen atoms. At the time we had no idea where the oxygen was coming from," said Candy Hansen, Cassini scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena. "Now we know Enceladus is spewing out water molecules, which break down into oxygen and hydrogen."
A Cassini image of Encaladus. The blue-green "tiger stripes" are thought to be the source of Enceladus's water jets. More. Image from: nasa.gov
Cassini's infrared spectrometer took the temperature of a tiger stripe. The fissure is at least 15 degrees K warmer than its surroundings--a sign of geothermal activity. More. Image from: nasa.gov
Scientists still have many questions. Why is Enceladus so active? Might this activity have been continuous enough over the moon's history for life to have had a chance to take hold in the moon's interior? In the spring of 2008, scientists will get another chance to look at the geysers--and another crack at answering these questions--when Cassini flies within 350 kilometers (approximately 220 miles) of Enceladus.
"There's no question, along with the moon Titan, Enceladus should be a very high priority for us," said Jonathan Lunine, Cassini interdisciplinary scientist, University of Arizona, Tucson, Ariz. "Saturn has given us two exciting worlds to explore."
Mission scientists report these and other Enceladus findings in this week's issue of Science.
Article from: http://science.nasa.gov/headlines/y2006/09mar_enceladus.htm?list109322
Scientists find source of Saturn ring
Saturns Rings. Image from: jpl.nasa.gov
An international team of scientists has found that the source of Saturn`s outer ring is water vapor from the planet`s moon Enceladus.
In an article in the journal Science, the researchers say that a plume of water vapor from Enceladus`s south pole has also given the moon a water-based atmosphere. They believe that internal processes within the moon are generating heat to produce the vapor.
The outer ring, known as the E-ring, stretches between the orbits of the moons Mimas and Titan. It is composed of microscopic particles.
The atmosphere was found during three fly-bys by the Cassini unmanned spacecraft in 2005. After researchers examined data from the first two fly-bys, they convinced the Cassini Project to bring the probe within 105 miles of Enceladus on the third.
'It was extremely exciting to have all the other instruments confirm our initial discovery, particularly when it was found that the atmosphere was changing from flyby to flyby and was closely linked with the subsequent plume observations at the South Pole,' said Michele Dougherty, a professor at Imperial College in London.
Cassini Huygens is a joint project of NASA and the European Space Agency.
Copyright 2006 by United Press International
Article from: http://people.monstersandcritics.com/
Related: Jets of Enceladus
Enceladus -- the basic facts
Cassini Discovers Potential Liquid Water on Enceladus -- NASA press release