Data from Cassini's composite infrared spectrometer of Enceladus' south polar terrain, which is marked by linear fissures, indicate that the internal heat-generated power is about 15.8 gigawatts, approximately 2.6 times the power output of all the hot springs in the Yellowstone region, or comparable to 20 coal-fueled power stations. This is more than an order of magnitude higher than scientists had predicted, according to Carly Howett, the lead author of study, who is a postdoctoral researcher at Southwest Research Institute in Boulder, Colo., and a composite infrared spectrometer science team member.
"The mechanism capable of producing the much higher observed internal power remains a mystery and challenges the currently proposed models of long-term heat production," said Howett.
It has been known since 2005 that Enceladus' south polar terrain is geologically active and the activity is centered on four roughly parallel linear trenches, 130 kilometers (80 miles) long and about 2 kilometers (1 mile) wide, informally known as the "tiger stripes." Cassini also found that these fissures eject great plumes of ice particles and water vapor continually into space. These trenches have elevated temperatures due to heat leaking out of Enceladus' interior.
A 2007 study predicted the internal heat of Enceladus, if principally generated by tidal forces arising from the orbital resonance between Enceladus and another moon, Dione, could be no greater than 1.1 gigawatts averaged over the long term. Heating from natural radioactivity inside Enceladus would add another 0.3 gigawatts.
The latest analysis, which also involved the composite infrared spectrometer team members John Spencer at Southwest Research Institute, and John Pearl and Marcia Segura at NASA's Goddard Space Flight Center in Greenbelt, Md., uses observations taken in 2008, which cover the entire south polar terrain. They constrained Enceladus' surface temperatures to determine the region's surprisingly high output.
A possible explanation of the high heat flow observed is that Enceladus' orbital relationship to Saturn and Dione changes with time, allowing periods of more intensive tidal heating, separated by more quiescent periods. This means Cassini might be lucky enough to be seeing Enceladus when it's unusually active.
The new, higher heat flow determination makes it even more likely that liquid water exists below Enceladus' surface, Howett noted.
Recently, scientists studying ice particles ejected from the plumes discovered that some of the particles are salt-rich, and are probably frozen droplets from a saltwater ocean in contact with Enceladus' mineral-rich rocky core. The presence of a subsurface ocean, or perhaps a south polar sea between the moon's outer ice shell and its rocky interior would increase the efficiency of the tidal heating by allowing greater tidal distortions of the ice shell.
"The possibility of liquid water, a tidal energy source and the observation of organic (carbon-rich) chemicals in the plume of Enceladus make the satellite a site of strong astrobiological interest," Howett said.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., 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 CIRS team is based at NASA's Goddard Space Flight Center in Greenbelt, Md., where the instrument was built.
For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20110307.html
- Fermi Telescope Caps First Year With Glimpse of Space-Time [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Antarctic Airborne Science Mission Nears Mid-Point [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA Awards Education Research Grants to Minority Universities [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- New Celestial Map Gives Directions for GPS [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA Invites Reporters to Tranquility Node Ceremony at Kennedy [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Happy Halloween [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA's Fermi Telescope Detects Gamma-Ray From "Star Factories" in Other Galaxies [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA Announces Advisory Council Chairs and Committee Structure [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA and X Prize Announce Winners of Lunar Lander Challenge [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- MESSENGER Spacecraft Reveals More Hidden Territory on Mercury [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Successful Flight Through Enceladus Plume [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Education Secretary Hosts DC Students for Talk with Space Station [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Operation Ice Bridge Studies Antarctic Sea Ice [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA West Point Welcomes Home One of Their Heroes [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA Spitzer Observes a Chaotic Planetary System [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- X-38 Crew Return Vehicle Finds New Home [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Frost-Covered Phoenix Lander Seen in Winter Images [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Have some faith He is doing his best [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- The Cross [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Spring Bloom in New Zealand Waters [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA Hubble image showcases star birth in M83, the Southern Pinwheel [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Take Me Out to the Ballpark - On Mars! [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Poisk Poised for Live NASA TV Space Station Docking [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Ceremony Reset for ESA Handover of Tranquility to NASA [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- NASA Reproduces a Building Block of Life in Laboratory [Last Updated On: November 8th, 2009] [Originally Added On: November 8th, 2009]
- Now Online: Aeronautics Goes E-Book [Last Updated On: December 12th, 2009] [Originally Added On: December 12th, 2009]
- Water on the Moon, Drought on Earth: NASA Experts Available for Radio And Podcast Interviews During Major Science Meeting [Last Updated On: December 12th, 2009] [Originally Added On: December 12th, 2009]
- Launch of NASA's Wise Spacecraft Delayed Until Dec. 14 [Last Updated On: December 12th, 2009] [Originally Added On: December 12th, 2009]
- Connecticut Students Set for Cosmic Conversation with Space Station Commander [Last Updated On: December 12th, 2009] [Originally Added On: December 12th, 2009]
- Magnetic Dance of Titan and Saturn To Be Main Attraction during Flyby [Last Updated On: December 12th, 2009] [Originally Added On: December 12th, 2009]
- Hubble's Deepest View of Universe Unveils Never-Before-Seen Galaxies [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Earth's Moon [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- How do you Make a Helicopter Safer to Fly? You Crash One. [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Physicist Earns Title as Kennedy's Best [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Hubble Unveils Never-Before-Seen Galaxies [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Saturn's Mysterious Hexagon Emerges from Winter Darkness [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Fermi Sees Brightest-Ever Blazar Flare [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Magnetic Power Revealed in Gamma-Ray Burst Jet [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Just 5 Questions: Aerosols [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Hometown Heroes 2009: Astronaut & Terrible Towel Return to Pittsburgh [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Garver Honors Four for Saving the Life of a Fifth at NASA Langley [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Administrator Bolden Speaks at AAIA-WIA Luncheon [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Best (Meteor) Shower of 2009 - No Towel Required [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- NASA Making Government More Accessible With Cutting-Edge Use Of New Media [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Scarce Water, Our Quiet Sun and Space Rocks Among NASA News Highlights at American Geophysical Union Meeting [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Press Credentials Deadlines Set for Next Space Shuttle Flight [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Reddish Dust and Ice Migration Darken Saturn's Moon Iapetus [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Galaxy Collision Switches on Black Hole [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- I’m watching the launch of NASA’s WISE spacecraft [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- SOFIA Aloft [Last Updated On: December 13th, 2009] [Originally Added On: December 13th, 2009]
- Guide to the International Space Station Laboratory Racks Interactive [Last Updated On: December 14th, 2009] [Originally Added On: December 14th, 2009]
- Freezing WISE's Hydrogen [Last Updated On: December 14th, 2009] [Originally Added On: December 14th, 2009]
- Local High School Wins Invention Challenge [Last Updated On: December 14th, 2009] [Originally Added On: December 14th, 2009]
- WISE Ready to Soar Into Space [Last Updated On: December 14th, 2009] [Originally Added On: December 14th, 2009]
- NASA Data Reveal Major Groundwater Loss in California's Heartland [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- NASA Looks for Safer Icing Forecast For Pilots [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- Challenges of Living and Working Aboard the Space Station: NASA Astronaut Nicole Stott Available for TV Interviews [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- NASA Astronaut, Food Scientist Available for Interviews about Holiday Feasts in Space [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- NASA Launches Web Site for Teenagers That Want More Class [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- A Unique Geography -- and Soot and Dust -- Conspire Against Himalayan Glaciers [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- New Study Turns Up the Heat on Soot's Role in Himalayan Warming [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- NASA's WISE Eye on the Universe Begins All-Sky Survey Mission [Last Updated On: December 15th, 2009] [Originally Added On: December 15th, 2009]
- NASA Offers Sound Clips for Radio, Online Newscasters [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- NASA Gets Up-Close Look at Far Corner of the Globe [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Orion Launch Abort System Attitude Control Motor Test-fired [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Hubble Finds Smallest Kuiper Belt Object Ever Seen [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- The Dark Side of Carbon [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- R97UYEA6HD8W [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- NASA's AIM Satellite and Models are Unlocking the Secrets of Mysterious "Night-Shining" Clouds [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Classroom Learning Takes Off with NASA-Funded Education Projects [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- NASA Buys Additional Space Shuttle Reusable Solid Rocket Motors [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Searching for New Vaccines and Studying Butterflies in Space; NASA Offers TV Interviews about Latest Space Station Science Research [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- NASA Partners with Saudi Arabia on Moon and Asteroid Research [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- New Results from a Terra-ific Decade in Orbit [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Deposits in Martian Trough Point to Complex Hydrological Past [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- NASA Outlines Recent Greenhouse Gas Research [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Unexpected Wheel-Test Results [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Solar Storms and Radiation Exposure on Commercial Flights [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Global Digital Elevation Model [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]
- Hubble's Festive View of a Grand Star-Forming Region [Last Updated On: December 17th, 2009] [Originally Added On: December 17th, 2009]