The Galileo spacecraft's close swing past Jupiter's moon Io last month has given scientists plenty to puzzle over. As the craft passed within a few hundred miles of the moon's violently volcanic surface, it took a series of images that are more detailed than ever before seen of Io.

The moon now actually appears to be hotter and more active than scientists had previously dared to imagine.

"The latest flyby has shown us gigantic lava flows and lava lakes, and towering, collapsing mountains," said Alfred McEwen, a planetary scientist at the of the University of Arizona who is a member of the Galileo imaging team. "Io makes Dante's Inferno seem like another day in paradise," he said. McEwen was speaking at a NASA press conference held to announce the release of the new images.

This image shows a region near Io's equator. It covers an area about 85 miles wide.

Some of the mountains, like the one pictured above, are not volcanoes, and scientists do not know how they form, but some appear to collapse into the moon under the force of gravity.

Scientists hope to learn more about dynamic Io when Galileo swoops down for an even closer look on Nov. 25 from an altitude of only 186 miles.