Featured Research

from universities, journals, and other organizations

Hot Spot On Saturn's Tiny Moon Enceladus Causes Icy Plumes

Date:
December 20, 2007
Source:
Washington University in St. Louis
Summary:
Enceladus, the tiny satellite of Saturn, is colder than ice, but data gathered by the Cassini-Huygens Mission to Saturn and Titan has detected a hot spot that could mean there is life in the old moon after all. The hot spot is causing plumes of ice and vapor to arise above Enceladus, say astronomers. If there is water on Enceladus, could there be life?

Hot spots on Saturn's tiny satellite Enceladus could be telltale signs of life on the frigid moon.
Credit: Photo courtesy NASA

Enceladus, the tiny satellite of Saturn, is colder than ice, but data gathered by the Cassini-Huygens Mission to Saturn and Titan has detected a hot spot that could mean there is life in the old moon after all. In fact, for researchers of the outer planets, Enceladus is so intellectually hot, it's smokin'.

The heat being generated on the moon's south pole at a hot spot is enough to eject plumes of ice and vapor above Enceladus. These plumes, according to William B. McKinnon, Ph.D., professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, are this moon's most intriguing feature.

"The plume particles are like smoke, ice smoke," McKinnon said. "If you were standing on Enceladus' surface you wouldn't even be able to see the plumes. The particles are just larger than the wavelength of light, about one-thousandths of a millimeter. Most icy bodies of this size are geologically inert, but this is a clear indication of geological activity. Cassini has found active venting of water vapor. This leads to scientifically intriguing speculations and questions."

One is: Is this active ice volcanism on Enceladus? If so, is it due to ice sublimating, in the manner of a comet, or to a different mechanism, like boiling water, as in Old Faithful at Yellowstone?

The biggest question: If there is water on Enceladus, is there life?

"I don't think so," McKinnon said. "The strongest piece of evidence against that is measurements made from Earth of the plume don't show any sodium. If the source of the plumes were fresh water like on Earth, the plumes would contain enough detectable sodium. Fresh water flows through rocks and on streambeds, and so it picks up bits of mineral chemistry. The emerging view is that there's not obvious evidence for a subterranean ocean in contact with rock, no boiling or venting."

McKinnon said that the leading model for the cause of the plumes on Enceladus is that the moon's tides cause its crust to ratchet or rub back and forth in a set of faults near the south pole. This action generates just enough heat to vaporize the ice that makes the plumes.

Cassini, which has been passing through the plumes of Enceladus, makes its next pass in March of 2008. It will go deeper into the plume and take more pictures of the moon's features, the venting area in the infrared, impact craters, cracks and fissures, and make better measurements of gases and vapors.

McKinnon presented "Cold Fire: The Geology and Geophysics of Enceladus," Dec. 10, 2007, at the Fall Meeting of the American Geophysical Union in San Francisco.

The mythological Enceladus is buried beneath Mount Etna and is responsible for the mountain's tremors and volcanism. The moon Enceladus is only 500 kilometers wide — roughly 300 miles wide, the distance between St. Louis and Chicago, and quite round for such a small body. Data from Cassini has revealed a rock-rich body, 55 to 60 percent rock by mass, with a surface of nearly pure water ice.

The temperature at the poles is some -220 degrees Celsius (C), but the hot spot is at least 100 degrees warmer. Enceladus is in a special relationship called dynamical resonance with another one of Saturn's moons, Dione. Every time Dione, in an exterior orbit around Saturn, circles Saturn, Enceladus goes around exactly twice. This resonance keeps Enceladus' orbit tidally pumped, maintaining an eccentric path that leads to a continuous squeezing under Saturn's gravity field.

This process makes a small part of the planet hot, relatively, for an icy satellite. It's the same mechanism that runs the tremendously hot silicate volcanism of Io and activates Europa, maintaining its ocean. Lo and Europa are two of Jupiter's moons.

"You only have to get so hot to make ice active," McKinnon said. "It doesn't have to get tremendously hot like it does on Lo. Ice volcanism requires an order of magnitude less energy for things to work out pretty well. The hot spots are -100 degrees C or possibly 'warmer'; the area around it is more than twice as cold. We still can't say how truly 'hot' the hot spots are. We'll probably learn this in March."


Story Source:

The above story is based on materials provided by Washington University in St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University in St. Louis. "Hot Spot On Saturn's Tiny Moon Enceladus Causes Icy Plumes." ScienceDaily. ScienceDaily, 20 December 2007. <www.sciencedaily.com/releases/2007/12/071217155253.htm>.
Washington University in St. Louis. (2007, December 20). Hot Spot On Saturn's Tiny Moon Enceladus Causes Icy Plumes. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2007/12/071217155253.htm
Washington University in St. Louis. "Hot Spot On Saturn's Tiny Moon Enceladus Causes Icy Plumes." ScienceDaily. www.sciencedaily.com/releases/2007/12/071217155253.htm (accessed July 24, 2014).

Share This




More Space & Time News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: ISS Cargo Ship Launches in Kazakhstan

Raw: ISS Cargo Ship Launches in Kazakhstan

AP (July 23, 2014) The Progress 56 cargo ship launched from the Baikonur Cosmodrome in Kazakhstan Wednesday. NASA says it will deliver cargo and crew supplies to the International Space Station. (July 23) Video provided by AP
Powered by NewsLook.com
Raw: Cargo Craft Undocks from Space Station

Raw: Cargo Craft Undocks from Space Station

AP (July 22, 2014) A Russian Soyuz cargo-carrying spacecraft undocked from the International Space Station on Monday. The craft is due to undergo about ten days of engineering tests before it burns up in the Earth's atmosphere. (July 22) Video provided by AP
Powered by NewsLook.com
NASA Ceremony Honors Moon Walker Neil Armstrong

NASA Ceremony Honors Moon Walker Neil Armstrong

AP (July 21, 2014) NASA honored one of its most famous astronauts Monday by renaming a historic building at the Kennedy Space Center in Florida. It now bears the name of Neil Armstrong, the first man to walk on the moon. (July 21) Video provided by AP
Powered by NewsLook.com
Neil Armstrong's Post-Apollo 11 Life

Neil Armstrong's Post-Apollo 11 Life

Newsy (July 19, 2014) Neil Armstrong gained international fame after becoming the first man to walk on the moon in 1969. But what was his life like after the historic trip? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins