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semimajor axis Syllabification: sem·i·ma·jor ax·is
Pronunciation: /ˈsemēˈmājər/ /ˈsemˌī-/

Definition of semimajor axis in English:


Either of the halves of the major axis of an ellipse.
Example sentences
  • The initial covariance matrices of each lander were set to correspond to a 15 by 8 kilometer landing ellipse with a semimajor axis in the East-West direction.
  • The speed of the satellite is inversely proportional to the square root of the radius of the orbit (or more strictly the semimajor axis of the orbit).
  • Kepler's third law of planetary motion says that the square of the planet's orbital period is proportional to the cube of its semimajor axis.
Definition of semimajor axis in:
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