The Universe and Solar System | Term 1 Unit 1 | Geography | 6th Social Science - Universe | 6th Social Science : Geography : Term 1 Unit 1 : The Universe and Solar System
Chapter: 6th Social Science : Geography : Term 1 Unit 1 : The Universe and Solar System
Universe
Universe
The Universe is a vast
expanse of space. Most astronomers believe that the Universe came into existence
after the Big Bang explosion that took place about 15 billion years ago. The universe
consists of billions of galaxies, stars, planets, comets, asteroids, meteoroids
and natural satellites. These are collectively called as celestial bodies, which
are located far away from each other. A Light year is the unit used to measure the
distance between the celestial bodies.
Galaxy
It is a huge cluster
of stars which are held together by gravitational force. Most of the galaxies are
scattered in space, but some remain in groups.
A light-year
is the distance traversed
by light in a year at a velocity of 300,000 km per second. Sound travels at a speed
of 330 m per second.
The Milky Way Galaxy
was formed about 5 billion years after the Big Bang explosion. Our solar system
is a part of the Milky Way galaxy. Andromeda
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