‘The Universe’
If we look at the sky on a clear
night, is seems to a kind of roof spreading over a flat earth. Our forefathers
believed that the earth was all flat and endless and the heavenly bodies were
silently moving across it.
But now we have come to know that the
earth is a small globe and it revolves around the sun. It is a part of the
solar system. In relation to the solar system, the earth is extremely small. It
can be compared to a fly. The moon going round the earth is smaller still
hardly the size of a pin-head. On the same scale, the sun can be compared to a
ball Of fire. The earth itself would be like a ball the size of a capital ‘O’. There
are eight more planets like our earth. All the nine planets circle round the
sun at various distances. Jupiter is the biggest planet. Many tiny moons circle
round various planets. The number of members (the sun and the tiny moons) in
our solar system is thirty.
The sun is one of the countless stars
in the sky. Most of the stars are also as big as our sun. Our sun is just an
insignificant member of the galaxy. The galaxy consists of at least a hundred
thousand million stars. The band of white stars which we see across the sky at
night is only a part of this galaxy. We also call it the milky way or the
heavenly Ganga. The galaxy is shaped like a biscuit, thick in the middle and
thin towards the edge. The galaxy turns round on its axis like a vast wheel.
The galaxy is packed with stars. The galaxy,
however is mostly empty. There is a vast distance between different stars. The nearest
star is about 5400 kms. away. The galaxy is extremely big. It is not possible
to measure its size in miles or kilometers. The astronomers use the unit
light-year which is the distance travelled by light in a year at the rate of
186,000 miles per second. The nearest star from the earth is four and a half
light-years away. The pole star is about 78 light years away from the earth.
Roughly, there are 150 million
galaxies in all. There is an average distance of two million light years
between two galaxies. The farthest galaxies are about 6000 million light-years
away from the earth. Everything in this universe is in motion whether it is an
atom or a galaxy. The galaxies revolve on their own axes.
The milky way contains some 2,000
nearby galaxies. The distant galaxies are all moving away from us and from each
other at an alarming speed. The galaxies are moving apart because our universe
has been expanding ever since the great explosion (big bang) some six hundred
crores of years ago. In the beginning, the universe must have been very small
and all the matter was closely packed in a limited space. Other astronomers who
believe in the steady state’ theory say that the universe has always existed
and will always exist as it is now.
There is a great probability, that
other planets too have thinking persons and living creatures on them. We cannot
hope to get in touch with them nor can we communicate with them.
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