Satellites

Satellites are natural or artificial bodies revolving around a planet under its gravitational force of attraction.

Moon is a natural satellite, While INSAT-B is an artificial satellite of Earth.

Geo-stationary satellites revolve around the Earth at the height of 36000 km (approximately). The orbit of geo-stationary satellites is called parking orbit. Geo-stationary satellites revolve in equatorial plane from West to East. Time period of rotation of geo-stationary satellites is 24 hours.

The Earth rotates on its axis from West to East. This rotation makes the Sun and Stars appears to be moving across the sky from East to West.

Geo-stationary satellites are used to telecast TV programmes from one part of the world to another, in weather forecasting, in prediction of floods and droughts.

Polar Satellite revolves around the Earth in polar orbit at a height of 800 km (approximately). Time period of this satellite is 84 minutes.

These are used for weather forecasting and mapping, etc.