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Young Saturn gave Jupiter the building blocks for its big moons

发布时间:2017-10-18 04:01:01来源:未知点击:

NASA/JPL/University of Arizona In the beginning of the solar system, Jupiter was a solo traveller. It was so big that it had carved out a path clear of dust and debris around the sun, leaving no material to build the massive moons that it has today. Then, Saturn began to form, and it may have tossed some rocks Jupiter’s way that later formed moons. Jupiter now has 69 moons, but its four biggest – Io, Europa, Ganymede, and Callisto – likely formed around Jupiter when the solar system was young,