Astronomy Fundamentals

Medieval Andrenaissance Astronomy

What is Kepler’s Second Law of planetary motion?

According to Kepler’s Second Law, planetary orbits sweep out equal times in equal areas. This means that a planet will move faster when it is closer to the Sun and slower when it is farther away. Future scientists, such as Isaac Newton, showed that the Second Law is true because of an important property of moving systems called “the conservation of angular momentum.”


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