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Astronomy & Space vocabulary · Orbits & Gravity

Kepler's laws

Meaning in astronomy & space, with examples

nounAdvanced term

In astronomy & space, Kepler's laws means: Three rules published by Johannes Kepler in the early 1600s: planets move in ellipses, they move faster when closer to the Sun, and orbit size is linked to orbital period.

In Turkish: Kepler yasaları

How it is used

Taught in physics and astronomy courses and used in everyday orbit calculations. People refer to Kepler's first, second or third law. The third law lets astronomers work out the mass of a star from the orbits of its planets.

Example sentences

  1. According to Kepler's second law, a comet moves fastest when it is closest to the Sun.

  2. Using Kepler's third law, we can calculate the planet's distance from its orbital period.

Common collocations

  • Kepler's first law
  • Kepler's third law
  • obey Kepler's laws
  • orbitThe curved path that an object such as a planet, moon or satellite follows around another object because of gravity. As a verb, it means to move along this path.
  • orbital periodThe time an object takes to complete one full orbit around another object. Earth's orbital period around the Sun is about 365.25 days.
  • gravityThe force that pulls any two objects with mass towards each other. It keeps the planets in orbit around the Sun and keeps our feet on the ground.
  • apogeeThe point in an orbit around Earth where a satellite or the Moon is farthest from Earth. The closest point is called the perigee.

More terms: Orbits & Gravity

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