Jupiter's Moon Europa: What Could Be Under The Ice?

Jupiter's moon Europa is just as far away as ever, but new research is bringing scientists closer to being able to explore its tantalizing ice-covered ocean and determine its potential for harboring life.

"We've learned a lot about Europa in the past few years," says William McKinnon, professor of Earth and Planetary Sciences at Washington University in St. Louis, Mo.

"Before we were almost sure that there was an ocean, but now the scientific community has come to a consensus that there most certainly is an ocean. We're ready to take the next step and explore that ocean and the ice shell that overlays it. We have a number of new discoveries and techniques that can help us do that."

McKinnon is discussing some of these recent findings and new opportunities for exploring Europa in a news briefing today at the meeting of the American Geophysical Union in San Francisco. He is joined by colleagues Donald Blankenship, research scientist at the Institute for Geophysics at the University of Texas at Austin's Jackson School of Geosciences., and Peter Doran, associate professor of Earth and Environmental Sciences, University of Illinois at Chicago.

McKinnon points to refined methods that can use combined measurements of gravity and the magnetic field made from orbit to characterize Europa's ocean. By observing how the moon flexes and deforms and by measuring magnetic variations, researchers can determine how thick or thin the ice is over the ocean and even learn how salty the ocean is. A new model shows that radiation on Europa is much less, up to two-thirds less, than previous models predicted, making the environment much more hospitable for orbiting spacecraft or landers to operate.

Sophisticated reprocessing of data from the Galileo mission has revealed new information about the chemistry of Europa's surface. It maps the presence of carbon dioxide, an important chemical for life, most probably coming from the ocean beneath the surface. This indicates that improved measurements from orbit have the chance to detect compounds not found in the Galileo data.

Future explorations of Europa will benefit from lessons learned from the Cassini spacecraft's recent findings of active geysers on Saturn's moon Enceladus. "Europa is a young, geologically active body like Enceladus," says McKinnon. Galileo didn't see any plumes on Europa like those spouting from Enceladus, but it didn't have the best instrumentation to detect the telltale hot spots. "Now we know what we should look for," says McKinnon, "and we should expect the unexpected." ...

•	Jupiter's Moon Europa: What Could Be Under The Ice? Science News ScienceDaily.com, Friday, Dec. 14, 2007

	Story also ran in 3 others:  Space Fellowship (UK), Space Daily (CA) and PhysOrg.com (VA)