Page 250 - New Medley 4 Semester 2 PDF (Merged)

Galaxy

A galaxy is a huge group of stars that contains billions of stars. Stars that are

visible to us belong to the Milky Way galaxy. There are billions of galaxies
in the universe. This makes the total number of stars in the night sky almost

uncountable. Does this give you an idea of the size of universe?

THE SOLAR SYSTEM

Our solar system is a part of the Milky Way galaxy. It consists of the sun, planets,

dwarf planets, moons and some other objects. The sun is at the centre of our solar
system. It is surrounded by 8 planets, over 61 moons and several other heavenly

objects. They all revolve around the sun in their fixed paths called orbits.

Mercury Earth Jupiter
Uranus

Venus Neptune
Mars Saturn

The solar system

Planets

In the night sky, there are shining heavenly bodies which do not twinkle. These
are called planets. Planets revolve around the sun or any other star. A planet

does not have heat and light of its own but reflects the light of its closest star.
That is why it shines in the night sky.

There are eight planets in our solar system. Starting from the sun, they are

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Earlier, Pluto was counted as the ninth planet. But, now it is considered a dwarf
planet because it does not have all the features of a planet.

Mercury and Venus can be located in the early mornings and late evenings. Mars

can be easily located in the night sky due to its reddish colour. Jupiter is the
largest and the heaviest planet in our solar system. Saturn has a large number

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