Big bang theory Geography Class XI ,Class XII CBSE Board

1. BIG BANG THEORY

2. Dear Sir/Madam
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3. INTRODUCTION
 The theory of Big Bang was put forward by an astronomer cum Belgian
priest named Georges Lamaitre in 1927 however,
 It was George Gamow who coined the term big bang in 1946.
 Gamow with R.AAlpher advocated a high temperature state in the
beginning of the universe.
 Edwin Hubble however presented reality with experiments to the theory
of Lamaitre.

4. BIG BANG

5. STAGES IN THE DEVELOPMENT OF THE
UNIVERSE
The Big Bang Theory considers the
following stages in the
development of the universe.
 (i) In the beginning, all matter
forming the universe existed in
one place in the form of a “tiny
ball” (singular atom) with an
unimaginably small volume,
infinite temperature and infinite

6. STAGES IN THE DEVELOPMENT OF THE
UNIVERSE
 (ii) At the Big Bang the “tiny ball” exploded
violently. This led to a huge expansion. It is
now generally accepted that the event of big
bang took place 13.7 billion years before the
present. The expansion continues even to
the present day. As it grew, some energy was
converted into matter. There was particularly
rapid expansion within fractions of a second
after the bang. Thereafter, the expansion has
slowed down. Within first three minutes from
the Big Bang event, the first atom began to
form.

7. STAGES IN THE DEVELOPMENT OF THE
UNIVERSE
(iii) Within 300,000 years
from the Big Bang,
temperature dropped to
4,500 K (Kelvin) and gave
rise to atomic matter. The
universe became
transparent.

8.  Our solar system began forming about 5 billion years ago as gas clouds
coalesce into planets and a star..Today the solar system contains nine
commonly recognized planets and the sun.
 Predictions associated with the Big Bang theory that have been tested
by this process are:
o If the Big Bang did occur, all the objects within the universe should be
moving away from each other:
o In 1929 Edwin Hubble documented that the galaxies in our universe are
indeed moving away from each other .

9. continued
o The BigBang should have left an “after glow” from the explosion :In
the1960’s scientists discovered the existence of cosmic background
radiation,The so called afterglow after the Big Bang explosion.
o If the universe began with a Big Bang, extreme temperatures should
have caused 25% of the mass of the universe to become helium: This
is exactly what is observed.
o Matter in the universe should be distributed homogeneously :
Astronomical observations from the Hubble space telescope do indicate
that matter in the universe generally has a homogeneous distribution.

10. continued
 As the universe expanded, matter began to coalesce into gas clouds and
then stars and planets.Our solar system formed about 5 billion years ago
when the universe was about 65% of its present size.Today the universe
continues to expand.
 The Big Bang theory postulated in 1950’s and 1960’s and passed in 1972
through convincing evidences received from Cosmic Background
Explorer
(Cobe) explains the origin of the universe.The universe contained many
millions of stars and each star having numerous planets around them.

11.  The majority of atoms that were produced by the Big Bang are
hydrogen,along with helium and traces of lithium.
 It is felt that the expansion of the universe will continue for a long time
from now. After that perhaps the expansion will slow down. At any point
of time, if similar condition prevails the cosmic eggs or atoms may become
active again and another explosion or bang may occur.

12. Dear Sir/Madam
For more
Please visit my YouTube Channel to learn computer
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For class IX & X Computer Class visit-:
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13. Thank you

14. Dear Sir/Madam
For more
Please visit my YouTube Channel to learn computer
https://www.youtube.com/yka39
For class IX & X Computer Class visit-:
www.it402.com