Page 78 - Science class 4

Unit-V : Routine Concepts

9 Sun, Planets and Stars

Inside
Inside l The universe
the l The Solar system
the
Chapter
Chapter
l Mercury, Venus, Earth, Mars, Jupiter. Saturn, Uranus,
Neptune

l Artificial Satellites

THE UNIVERSE

A vast space that is seen when we
look up in the sky is called the
universe. It includes all the heavenly

bodies like the stars, planets, moons
meteorites and comets.

Scientists believe that the universe
began with a vast explosion called

Universe
Universe
Big Bang about 15 billion years ago. Universe
Minutes after the explosion, atomic particles combined together to make the
gases helium and hydrogen . Over millions of years, these gases formed the

universe and all the stars and galaxies within it. Even parts of the universe are
still forming.

Let us now learn about universe

Everything that exists is the universe, is
what we have learnt. The Earth on which

we live is also a part of the universe.
Similarly the Sun, the Moon and the stars

are also a part of the universe. If we look at
the sky in the night, we can see a galaxy of
Stars
Stars stars twinkling. A star is a hot ball of gases.
Stars
The stars emit their own heat and light. The Sun is also a star. There are some

stars which are thousand times bigger than the Sun. The stars are grouped by
our ancestors under different names. These groups of stars are called

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