Galileo Sends Christmas Joy From Space

As stunning, new photos of the strange moon called Ganymede come in from 400 million miles in space, “it’s like Christmas every day,” said scientist Jim Head. “Every morning, we come rolling in to open a new package from Ganymede.”

Head, a Brown University scientist on the imaging team for the orbiter Galileo, which flew by Ganymede last month, said the photos “are fantastic. They’re 20 times better than anything we’ve ever been able to see” on the icy moon that orbits Jupiter. Until now, the best images were those returned by two Voyager spacecraft, which sped past Jupiter in 1979.

The new photos and other data are the first to come back from the complex Galileo mission to Jupiter. The big spacecraft reached Jupiter Dec. 7, and after dropping its probe into the big planet’s atmosphere, it began a two-year journey to explore Jupiter’s four biggest moons. The first images, from Ganymede, were released Wednesday.

Each image and each instrument seems to deliver a major surprise, researchers said Wednesday. In addition to detailed images of a rough, icy, pock-marked surface, instruments aboard the 2.5-ton spacecraft also indicate that Jupiter’s biggest moon has a magnetic field all its own.

“About 45 minutes before closest approach,” said Torrence Johnson, “two instruments gave us a very exciting result: Ganymede probably has a magnetic field.