Question

What are Geostationary satellites? Why are they called communication satellites?

Answer 1

We are asked about geostationary satellites. To answer this question you must first know the meaning of satellites and where they are placed. Then recall the definition of a geostationary satellite. In the second part we are asked why geostationary satellites are known as communication satellites. Communication means sending or receiving signals, use this concept to answer the second part of the question.

Complete answer:
Geostationary satellites are satellites that orbits around the earth and these are placed above the earth’s equator, it revolves around the earth in the same direction as that of earth and takes $24$ hours to complete one rotation or we can say it has an orbital period equal to the earth’s rotational period so, from ground geostationary satellites appears to be motionless.

Geostationary satellites are called communication satellites as geostationary satellites have same orbital period as that of earth and appears at a fix position with respect to earth so, the satellites antennas do not required to track their position and they can be pointed permanently towards a particular position in the sky where the geostationary satellite is located that is information can be sent or received easily. This is why geostationary satellites are known as communication satellites.

Note: Some of the applications of geostationary satellites which we observe in our day to day life are;
-Satellites which are used for weather forecasting.
-Communication satellites such as Dish antennas of TV.
-Satellites for GPS or Global Positioning System.