Ancient asteroid 20 times bigger than the one that wiped out the dinosaurs likely hit Jupiter’s moon Ganymede

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A new study finds that Jupiter's moon Ganymede may have been shifted off its axis about 4 billion years ago when a massive asteroid struck the moon.

Ganymede, the largest moon in the solar system, is even bigger than Mercury and the dwarf planet Pluto. And previous research has found evidence suggesting that beneath its thick, icy crust lies a salty ocean 10 times deeper than Earth's oceans.

However, many questions remain about the moon, and scientists need more high-resolution ...