Featured Research

from universities, journals, and other organizations

Galileo Findings Boost Idea Of Other-Worldly Ocean

Date:
January 11, 2000
Source:
NASA/Jet Propulsion Laboratory
Summary:
When NASA's Galileo spacecraft swooped past Jupiter's moon Europa a week ago, it picked up powerful new evidence that a liquid ocean lies beneath Europa's icy crust. As the spacecraft flew 351 kilometers (218 miles) above the icy moon on January 3, its magnetometer instrument studied changes in the direction of Europa's magnetic field. Galileo's magnetometer observed directional changes consistent with the type that would occur if Europa contained a shell of electrically conducting material, such as a salty, liquid ocean.

When NASA's Galileo spacecraft swooped past Jupiter's moon Europa a week ago, it picked up powerful new evidence that a liquid ocean lies beneath Europa's icy crust.

Related Articles


As the spacecraft flew 351 kilometers (218 miles) above the icy moon on January 3, its magnetometer instrument studied changes in the direction of Europa's magnetic field. Galileo's magnetometer observed directional changes consistent with the type that would occur if Europa contained a shell of electrically conducting material, such as a salty, liquid ocean.

"I think these findings tell us that there is indeed a layer of liquid water beneath Europa's surface," said Dr. Margaret Kivelson, principal investigator for the magnetometer. "I'm cautious by nature, but this new evidence certainly makes the argument for the presence of an ocean far more persuasive."

It appears that the ocean lies beneath the surface somewhere in the outer 100 kilometers (60 miles), the approximate thickness of the ice/water layer, according to Kivelson, a researcher at the University of California, Los Angeles (UCLA).

"Jupiter's magnetic field at Europa's position changes direction every 5-1/2 hours," Kivelson explained. "This changing magnetic field can drive electrical currents in a conductor, such as an ocean. Those currents produce a field similar to Earth's magnetic field, but with its magnetic north pole -- the location toward which a compass on Europa would point -- near Europa's equator and constantly moving. In fact, it is actually reversing direction entirely every 5-1/2 hours."

On previous Europa flybys, Galileo identified a magnetic north pole, but did not determine whether its position changes with time. "We wondered, 'Was it possible that the north pole did not move?' " Kivelson said.

The new evidence was gathered during a flyby specially planned so that the observed position of Europa's north pole would make it clear whether or not it moves. In fact, Monday's data showed that its position had moved, thus providing key evidence for the existence of an ocean.

It is not likely that the electric currents on Europa flow through solid surface ice, Kivelson explained, because ice is not a good carrier of currents. "But melted ice containing salts, like the sea water found on Earth, is a fairly good conductor," she said.

There is no other likely current-carrying material near Europa's surface, Kivelson added. "Currents could flow in partially melted ice beneath Europa's surface, but that makes little sense, since Europa is hotter toward its interior, so it's more likely the ice would melt completely. In addition, as you get deeper toward the interior, the strength of the current- generated magnetic field at the surface would decrease."

These latest findings are consistent with previous Galileo images and data showing a tortured surface seemingly formed when Europa's surface ice broke and rearranged itself while floating on a sea below. Further theoretical work is under way to analyze the fluid layer and its properties.

"It will be interesting to see whether this same type of phenomenon occurs at Jupiter's moon Ganymede," Kivelson said. Galileo is tentatively scheduled to fly by Ganymede twice this year.

Kivelson is joined in her magnetometer studies by Drs. Krishan Khurana, Christopher Russell, Raymond Walker, Christophe Zimmer, Martin Volwerk of UCLA, as well as Steven Joy and Joe Mafi, also of UCLA, and Dr. Carole Polanskey of NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA.

Additional information and pictures taken by Galileo are available at

http://galileo.jpl.nasa.gov

The Galileo mission is managed for NASA's Office of Space Science, Washington, D.C. by JPL, a division of the California Institute of Technology, Pasadena, CA.


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Jet Propulsion Laboratory. "Galileo Findings Boost Idea Of Other-Worldly Ocean." ScienceDaily. ScienceDaily, 11 January 2000. <www.sciencedaily.com/releases/2000/01/000111075538.htm>.
NASA/Jet Propulsion Laboratory. (2000, January 11). Galileo Findings Boost Idea Of Other-Worldly Ocean. ScienceDaily. Retrieved January 30, 2015 from www.sciencedaily.com/releases/2000/01/000111075538.htm
NASA/Jet Propulsion Laboratory. "Galileo Findings Boost Idea Of Other-Worldly Ocean." ScienceDaily. www.sciencedaily.com/releases/2000/01/000111075538.htm (accessed January 30, 2015).

Share This


More From ScienceDaily



More Space & Time News

Friday, January 30, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Holds Memorial to Remember Astronauts

NASA Holds Memorial to Remember Astronauts

AP (Jan. 29, 2015) NASA is remembering 17 astronauts who were killed in the line of duty and dozens more who have died since the agency&apos;s beginning. A remembrance ceremony was held Thursday at NASA&apos;s Marshall Space Flight Center in Alabama. (Jan. 29) Video provided by AP
Powered by NewsLook.com
Asteroid's Moon Spotted During Earth Flyby

Asteroid's Moon Spotted During Earth Flyby

Rumble (Jan. 27, 2015) Scientists working with NASA&apos;s Deep Space Network antenna at Goldstone, California discovered an unexpected moon while observing asteroid 2004 BL86 during its recent flyby past Earth. Credit to &apos;NASA JPL&apos;. Video provided by Rumble
Powered by NewsLook.com
Water Fleas Prepare for Space Voyage

Water Fleas Prepare for Space Voyage

Reuters - Innovations Video Online (Jan. 26, 2015) Scientists are preparing a group of water fleas for a unique voyage into space. The aquatic crustaceans, known as Daphnia, can be used as a miniature model for biomedical research, and their reproductive and swimming behaviour will be tested for signs of stress while on board the International Space Station. Jim Drury went to meet the team. Video provided by Reuters
Powered by NewsLook.com
Mars Rover Opportunity Celebrates 11-Year Anniversary

Mars Rover Opportunity Celebrates 11-Year Anniversary

Rumble (Jan. 26, 2015) Eleven years ago NASA&apos;s Opportunity rover touched down on Mars for what was only supposed to be a 90-day mission. Since then it has traveled 25.9 miles (41.7 kilometers), further than any other off-Earth surface vehicle has ever driven. Credit to &apos;NASA&apos;. Video provided by Rumble
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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