Page 182 - Science Class 08
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v One of these galaxies is the spiral-shaped
Andromeda. It is 2,000,000 light years away.
It is about twice the size of the Milky Way.
v There are different types of galaxies. Spiral
galaxies have arms. Irregular galaxies like the
large Magellanic cloud have no special
shape. Ellip cal galaxies are shaped like a
football or a slightly fla ened sphere.
Peculiar galaxies have some special features
such as an exploding centre.
A er studying this chapter, you will know
about the vastness of the universe. v Our galaxy has two companion galaxies, the
large and small Magellanic Cloud which can
GALAXIES
be seen in the southern hemisphere.
A galaxy is a vast collec on of billions of stars,
v Scien sts believe that all galaxies are
planets, dust and gases. At the centre of galaxy
is the galac c nucleus. Around the nucleus moving away from each other at high
speed.
is the galac c dick containing stars of all ages
and sizes. STARS
When its day, what we can see in the sky, is the
sun. But, as the night comes, we start seeing
some objects which twinkle. So, those twinkling
bodies are stars.
Star is a luminous body because it can emit its
own light.
The size of a star is bigger than that of the
earth. Some of the stars are even bigger than
There are millions of galaxies in the universe.
sun. As they are far away from us, hence, they
The Milky Way is the galaxy in which our earth
look so ny. We can see them in night only
and the solar system are present. because during day, the light of the sun is so
Facts About the Milky Way intense that it becomes difficult to see them.
v It is a strip of faintly glowing stars from Likewise we have some stars like objects
north to south across the sky. present in our sky which do not twinkle, but
they keep on shining. They are known as
v The Milky Way is spiral shaped something
planets. But before we study about the planets,
like a pin-wheel.
we will first talk about stars.
v It contains over 100 billion stars including
The sun which is also a star is 150,000,000
our sun.
kilometers (150 million km) away from the
Some Important Facts About Galaxies
earth. The next nearest star is Alpha Centauri. It
v There are about sixteen galaxies within is at a distance of about 40,000,000,000,000
3,000,000 light years of the earth. km from the earth.
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