A geostationary satellite must have an orbital period of

  • A. 1 hour
  • B. 12 hours
  • C. 24 hours
  • D. 365 days

Explanation

To stay above the same point on the equator the satellite must complete one orbit in exactly the time the Earth takes to rotate once, which is 24 hours. This fixes the orbital radius at about 42,300 km from the centre of the Earth. Communication and television satellites use this orbit so that a dish on the ground can be aimed once and left fixed.

Related questions