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2010-01-24 13:49:38

Differences in the number and speed of cometary impacts onto Jupiter's large moons Ganymede and Callisto some 3.8 billion years ago can explain their vastly different surfaces and interior states


Word of the Day
pawl
  • A pivoted catch designed to fall into a notch on a ratchet wheel so as to allow movement in only one direction (e.g. on a windlass or in a clock mechanism), or alternatively to move the wheel in one direction.
The word 'pawl' probably comes from a Latin word meaning 'stake'.
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