Galileo Turns Geology Upside Down on Jupiter's Icy Moons

摘要

When Galileo Galilei turned his rudimentary telescope on Jupiter almost 4 centuries ago, he saw four points of light hugging the immense disc of the planet. That first glimpse of Jupiter's moons was amplified over the years, as later astronomer distinguished at least 16 satellites orbiting the planet. But-it wasn't until 1979, when two Voyager spacecraft whizzed by Jupiter, that those four bright dots were transformed into individual worlds that a geologist could try to understand. Now, that exploration has taken another big step forward, as the spacecraft Galileo offers a longer, more intimate look at die Jovian system--including closeup images that are overturning scientists' ideas about the geology of' these icy moons.