The document summarizes the evolution of the universe. It discusses the origin and formation of the universe according to the Big Bang theory. The universe began as a very hot and dense state around 13.8 billion years ago, which then expanded and cooled to form stars, galaxies, and other celestial objects. The document also describes the components that make up the universe such as galaxies, stars, and black holes. It discusses the chemical composition and forces that govern the motion of objects in the universe.

1. seminar on
Evolution of universe

2. Contents
 Introduction
 Origin of Universe
 Various theories
-The Steady State Theory
-The Pulsating Theory
-The Big Bang Theory
 Big Bang Expansion
 Chronology
 Components of Universe
 Characters of universe
- Forces of universe
-Chemical composition
- Motion of objects
 Conclusion
 References

3. Introduction
 The universe is believed to be at least 10 billion light years
in diameter and contains a vast number of galaxies and has
been expanding ever since.
 The Universe is the totality of existence, This
includes planets, stars, galaxies, the contents of intergalactic
space.
 The size of the whole universe is not known and may be
infinite.

4.  These observations suggest that the Universe has been
governed by the same physical laws and constants throughout
most of its extent and for all time.
 Assuming that the prevailing model is correct, the age of the
Universe is measured to be 13.798 ± 0.037 billion years.
 Space in the Universe is expanding, and the rate of its
expansion is increasing.

5. The study of the origin of the universe and of subsystems of
the universe is the subject of Cosmology and it includes
 creation of the universe
 Age of the universe
 Formation of galaxies
 Formation of clusters of galaxies
 Formation of galaxies and clusters in steady -state
cosmology
 Age distribution of galaxies in the cosmologies

6. The Origin of the Universe
 In 1959 a survey was conducted by scientists across America
concerning the concept of age of the universe.
 More than two thirds of the scientists polled responded that there was
no origin of the Universe and they believed that the universe was
eternal.
 Then five years later, in 1964, radio astronomers Arno Penzias and
Robert Wilson discovered a microwave signal buried in their data.
 They realized that the signal actually was the Cosmic Microwave
Background (CMB) which they had inadvertently discovered .
 This discovery was the first evidence that the Universe had a
beginning.

7. various theories of the origin of
Universe
There are three main theories
1. The Steady State Theory
2. The Pulsating Theory
3. The Big Bang Theory

8. 1.The Steady State theory
It states that the counting of
the galaxies in our Universe is constant and
new galaxies which are forming
continuously are filling the empty spaces
which are created by those heavenly bodies
which have crossed the boundary lines of
observable Universe.

9. 2.The Pulsating Theory
 In this theory it is assumed that there is continuous expansion and
contraction in universe. A word which can replace the
above definition is ‘Pulsating’.
 Pulsating theory states that it is the possibility that after some
passage of time, the expansion in the universe may stop. Then their
may be the possibility of contraction.
 When this contraction will approach to a particular size. Again the
explosion will take place. As a result of this explosion the expansion
of universe will start again.
 Hence it results in a pulsating universe in which there
is alternate expansion and contraction of universe.

10. 3.The Big Bang Theory
 It states that all the matter of universe was present at a single place in the
form of hot and dense fire ball, having a high temperature of nearly 1012K.
 After the passage of nearly 20 billion years, an enormous explosion took
place. All the matter which was concentrated at one place scattered into
space with rapid speed. This scattering was along all directions.
 Then this scattered matter took the shapes of galaxies and stars.
 According to Hubble’s, the velocity of light and the recession velocities
of galaxies become similar at a distance of 20 billion light years.

11.  So, it is sure that these heavenly bodies which are present at a
distance of more than 20 billion light years can never arrive
near us. From the above discussion an observable boundary
of the universe is drawn.
 If the recession will remain in continuity then
large number of heavenly bodies will move away from us.
 Hence as a result, they will be lost one day. So, number of
stars and galaxies will reduce continuously and a day will
come when we will be surprised to see our empty universe.

12. Big Bang Expansion

13. Chronology
 According to the prevailing scientific model of the Universe,
known as the Big Bang the Universe expanded from an extremely
hot, dense phase called the Planck epoch.
 It is a brief period extending from time zero to approximately
10−43 seconds (the Planck time).
 During the Planck epoch, all types of matter, all types of energy,
and all space time were concentrated into a dense state, where
gravitation is believed to have been as strong as the
other fundamental forces and all the forces may have
been unified.
 Since the Planck epoch, the Universe has been expanding to its
present form, possibly with a very brief period (less
than 10−32 seconds) of cosmic inflation,
 It caused the Universe to reach a much larger size almost
instantaneously.
 Several independent experimental measurements support this
theoretical expansion.

14. Components of
Universe
Globular cluster- A spherically
symmetric collection of stars which
shared a common origin. The cluster may
contain up to millions of stars spanning up
to 50 parsecs.
Galaxy- A system of about
100 billion stars. Our Sun is
a member of the Milky
Way Galaxy. A galaxy is a
collection of stars and
planets that are held together
by gravity.

15. white dwarf star- A white dwarf star is
the final evolutionary phase of a star,
occurring after low- and medium-mass
stars lose the necessary mass to support
carbon-fusing temperatures.
Binary star- A binary star is
a star system consisting of
two stars orbiting around their
common center of mass.

16. Neutron star- A neutron star is
a type of stellar remnant that
can result from
the gravitational collapse of a
massive star after a supernova.
 Neutron stars are the densest
and smallest stars known to
exist in the universe; with a
radius of only about 12–13 km
(7 mi)
Black hole- A black hole is a
mathematically defined region
of spacetime exhibiting such a
strong gravitational pull that no
imminent particle or electroma
gnetic radiation can escape
from it.

17. Pulsar- Pulsars are fast-
spinning, highly radiating
neutron stars. Most pulsars
emit radio, X-ray and gamma
radiation at regular intervals.
Quasar-A massive and extremely
remote celestial object, emitting
exceptionally large amounts of
energy, which typically has a star
like image in a telescope. It has
been suggested that quasars
contain massive black holes and
may represent a stage in the
evolution of some galaxies.

18. Asteroid: are minor
planets, especially
those of the inner
Solar System. The
larger ones have also
been called
planetoids.
Meteorite- Extra
terrestrial bodies
which is not a part of
the earth.
Solar system-A solar
system refers to a star
and all the objects that
travel in orbit around
it. Our solar system
consists of the sun -
our star - eight planets
and their natural
satellites .

19. Comet- A comet is an
icy small Solar System
body that, when passing
close to the Sun, heats
up and begins to outgas,
displaying a visible
atmosphere or coma, and
sometimes also a tail.
Planet- a celestial body
moving in an elliptical
orbit round a star the
earth.

20. Characters of universe
 Forces of universe
 Chemical composition
 Motion of objects

21. Chemical composition
 The matter in typical stars of our galaxy has a
composition of
Hydrogen 67%
Helium 30%
Heavier Elements 3%
 Heavier elements are an artifact of galaxy and many of
the oldest stars of the galaxy have negligible abundance
of heavy elements .
 Typically have Helium abundance comparable with our
own galaxy
 At some early epochs when the densities and
temperature in the universe is high.

22. Forces
Matter is effected by forces or interactions (the terms are
interchangeable). There are four fundamental forces in the
Universe:
1.Gravity
2.Electromagnetism
3.Strong nuclear force
4.Weak nuclear force

23. Motion of the Objects
 Distant objects in the universe are receding from us.
 Present observations of this effect are adequately
described by stating that the recessional velocities
increase linearly with distance.
 At a distance of 3 x 107 light-years the recessional
velocities is 108 cm/sec.

24. Conclusion
 The age of the Universe is measured to be 13.798 ± 0.037 billion years.
 It includes planets, stars, galaxies, the contents of intergalactic space.
 From the origin of the universe, it is being explained through many
aspects.
 The Big Bang theory is the prevailing cosmological model that
describes the development of the Universe.
 Scientific observation of the Universe has led to inferences about its
evolution.
 Characters of universe are: Forces of universe, Chemical composition
of the universe , Motion of objects in universe.

25. References
 Rhodes W.Fairbridge ,The Encyclopedia of Atmospheric
sciences and AstroGeology, 1967, Newyork Amsterdam
London, Pp271-272,403 & Pp.1062-1064.
 David.E.Tavel, Evolution: The Universe, Life, Cultures,
Ethnicity, Religion, Science, and Technology, 2012,
Dorrance publications, Pp 1-12.
 http://en.wikipedia.org/wiki/Universe.
 en.wikipedia.org/wiki/Chronology of the universe.