define solar system s
Answers
Answer:
The sun and the eight planets revolving around it constitute the solar system.
Explanation:
Answer:
The sun, eight planets, satellites and some other
celestial bodies known as asteroids and meteoroidsform the solar system. We often call it a solar family,
with the sun as its Head.
The Sun
The sun is in the centre of the solar system. It is huge
and made up of extremely hot gases. It provides the
pulling force that binds the solar system. The sun is
the ultimate source of heat and light for the solar
system. But that tremendous heat is not felt so much
by us because despite being our nearest star, it is far
away from us. The sun is about 150 million km away
from the earth.
Planets
There are eight planets in our solar system. In order of
their distance from the sun, they are: Mercury,
Venus, Earth, Mars, Jupiter, Saturn, Uranus and
Neptune All the eight planets of the solar system move
around the sun in fixed paths. These paths are
elongated. They are called orbits. Mercury is nearest
to the sun. It takes only about 88 days to complete
one round along its orbit. Venus is considered as
‘Earth’s-twin’ because its size and shape are very much
similar to that of the earth.
Till recently (August 2006), Pluto was also
considered a planet. However, in a meeting of the
International Astronomical Union, a decision was
taken that Pluto like other celestial objects (Ceres, 2003
UB313) discovered in recent past may be called
‘dwarf planets.”
The Earth
The earth is the third nearest planet to the sun. In
size, it is the fifth largest planet. It is slightly flattened
at the poles. That is why, its shape is described as a
Geoid. Geoid means an earth-like shape.Conditions favourable to support life are probably
found only on the earth. The earth is neither too hot
nor too cold. It has water and air, which are very
essential for our survival. The air has life-supporting
gases like oxygen. Because of these reasons, the earth
is a unique planet in the solar system.
From the outer space, the earth appears blue
because its two-thirds surface is covered by water. It
is, therefore, called a blue planet.
The Moon
Our earth has only one
satellite, that is, the
moon. Its diametre is
only one-quarter that of
the earth. It appears so
big because it is nearer to
our planet than other
celestial bodies. It is
about 3,84,400 km away
from us. Now you can
compare the distance of
the earth from the sun
and that from the moon.
The moon moves around the earth in about 27 days.
It takes exactly the same time to complete one spin. As
a result, only one side of the moon is visible to us on
the earth.
The moon does not have conditions favourable for
life. It has mountains, plains and depressions on itssurface. These cast shadows on the moon’s surface.
Look at the full moon and observe these shadows.
Asteroids
Apart from the stars, planets and satellites, there are
numerous tiny bodies which also move around the
sun. These bodies are called asteroids. They are found
between the orbits of Mars and Jupiter .
Scientists are of the view that asteroids are parts of a
planet which exploded many years back.
Meteoroids
The small pieces of rocks which move around the sun
are called meteoroids. Sometimes these meteoroids
come near the earth and tend to drop upon it. During
this process due to friction with the air they get heated
up and burn. It causes a flash of light. Sometimes, a
meteor without being completely burnt, falls on the
earth and creates a hollow.
Do you see a whitish broad band, like a white
glowing path across the sky on a clear starry night? It
is a cluster of millions of stars. This band is the Milky
Way galaxy (Figure 1.6). Our solar system is a part of
this galaxy. In ancient India, it was imagined to be a
river of light flowing in the sky. Thus, it was named
Akash Ganga. A galaxy is a huge system of billions of
stars, and clouds of dust
and gases. There are
millions of such galaxies
that make the Universe.
It is difficult to imagine
how big the universe is.
Scientists are still trying
to find out more and more
about it. We are not
certain about its size but
we know that all of us –
you and I belong to this
universe.