Written by: Snighdha Chaudhary - 30047, Grade IV
Posted on: 04 February, 2022
When we look at the sky, we see different kinds of natural bodies like the sun, the stars, the moon, and so on. The natural bodies in the sky are called heavenly bodies. They are part of our universe. The universe is a huge space that contains everything that exists. The heavenly bodies that we see are just a small fraction of the bodies that exist in the universe. One of the reasons why we do not see more of them is that they are very, very far away.
To measure the large distances in the universe, scientists use a unit of length called the light year. A light-year is a distance travelled by light in one year. Light travels 9.46 trillion km in a year.
Scientists believe that the universe was born after a massive explosion called the ‘big bang’. A long time after the big bang, stars like our sun were formed. At that time, clouds of hot gases and particles revolved around the sun. Over time, many particles got stuck together to form large bodies. These bodies pulled in smaller objects near them by gravitational force. This made them larger still. These bodies finally became the planets.
