Archive for circular orbits

A Problem with a Geostationary Orbit

Posted in Cute Problems, The Universe and Stuff with tags , , , on September 26, 2018 by telescoper

I’ve been sorting through some old problem sets for my course on Astrophysics and Cosmology, and thought I would post this one in the Cute Problems folder for your amusement. The first part is easy, the second part not so much…

  1. Verify that the radius of a circular geostationary orbit around the Earth is about 42,000 km, i.e. find the radius of a circular  orbit around the Earth which has a period of 24 hours so it is always above the same point on the Earth’s surface . (You will need to look up the mass of the Earth.)
  2. Use the answer to (1)  to estimate what fraction of the Earth’s surface is visible at any  time from a satellite in such an orbit. (You will need to look up the radius of the Earth.)

Answers to (2) through the comments box please – and don’t forget to explain your working!

Advertisements