At night numberless stars twinkle in the sky.

They are constant.

They shine by their own light.

In day time we cannot see it, due to the dazzling light of the sun. They are far remote from the earth. So we can not feel their heat and light. We express the distance of stars from the earth in terms of `light year’

``Light year is that distance which is travelled in year by a light ray with a speed of three lac kilometers per second.’’

Some stars are in a group. This is called constellation. At night we see a group of seven stars in the north. This is called Saptarishi Mandal. In the north before first two stars of Saptarishi Mandal there is a very shining star. This is called pole star. By the help of this pole star we can know the directions.

In the east of saptarishi Mandal there is a group of fifteen stars. This called Kaal Purush constellation.

In the same way other group of stars is – Orion (the hunter), Southern Cross, Ursa Major (great bear), Scorpios and Leo etc.

*In our country in Bangalore near Kodaiknal there is Indian space research organization. It is a center to study about all the heavily bodies or Astronomical bodies 9sun, moon, stars, planets and satellites etc).

Main points

• Earth is such a strange planet which has life.
• In Japan sun rises first, for this reason Japan is called the `Country of rising sun’.
• When is day in India, it is night in America.
• Moon is a natural satellite of the earth. It is invisible in dark night. The full moon is visible in full moon-lit-night.
• Light year is that distance which is travelled in a year by a light ray with a sped of three lac kilometers per second.
• Some constellations are –Saptarishi Mandal, Kaal Purush, Orion, Southern Cross, Ursa Major, Scorpios and Leo etc.