All the objects in the sky are called heavenly bodies or celestial bodies. The sun, the moon, the stars and the planets, including the earth, are celestial bodies. We cannot see many of the other celestial bodies because they are very, very far from us.
The celestial bodies are spread over a very vast Space. This vast space containing all the celestial
bodies is called the universe. The universe is so huge that it is difficult to imagine its size. Just think of it in this way: the night sky that you see with all
its celestial bodies is just a tiny part of the universe.
If you were able to see the entire universe, all the
celestial bodies that you see now would together look like a tiny spot of light! You would not be able
to see the earth or even the sun!