crhedBngr
Justice for Danielle Stislicki
- Joined
- Jul 26, 2015
- Messages
- 5,832
- Reaction score
- 49,199
Millions of reasons why not. For one, the Earth is round. Satellites orbit round the earth. Even satellites have "black out periods". Hence why many countries like N. Korea wait until certain times to move large weapons, etc. It won't appear on the image until the satellite's next orbit or it could be well gone before the satellite comes back round. They are not stationary objects in space.
There are geostationary satellites.
Geostationary satellites have a different trajectory to polar satellites – they are in orbit above the equator. The height of their orbit - 36,000 km - is just the right distance so that it takes them one day (24 hours) to make each orbit. This means that they stay in a fixed position over the Earth’s surface. Geostationary satellites have uses such as:
Geostationary satellites always appear in the same position when seen from the ground. This is why satellite television dishes can be bolted into one position and do not need to move.
- communications - including satellite TV
- global positioning or GPS - which is used for sat navs (satellite navigation systems)
BBC - GCSE Bitesize Science - Satellites, gravity and circular motion : Revision, Page 2