This is a self-made presentation about The Big Bang Theory (NOT the TV show :P) to be given to a lecturer and students of University level. Intended for all those to download who may have presentations to give and can't find a good enough topic :). Everyone else is free to download it for other purposes as well!!

1. By: rose_aries15
Year 2
H62BPA: Presentation Skills
University of Nottingham, Malaysia Campus.
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2.  Premise
 History & Development
 Problems & Evidence
 Expansion of the Universe
 Common Misconceptions
 Summary
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3.  Discoveries in astronomy and physics have
shown beyond a reasonable doubt that our
universe did have a beginning: It all started with
an explosion known as the Big Bang (BB).
 The Big Bang theory and the term BB generally
refers to the idea that this mysterious universe
has expanded from a very hot and dense initial
condition at some time in the past, and it
continues to expand.
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4.  The Big Bang theory is basically an effort to
explain what happened at the very beginning
of our universe.
 Prior to the moment when the universe
began, there was nothing; during and after that
moment there was something: our universe. The
big bang theory explains what happened
during and after that moment.
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5.  According to the standard theory, our universe
sprang into existence as singularity around 13.7
billion years ago. Singularities are zones which
defy our current understanding of physics.
 A singularity is a point where the predictable
nature of physics breaks down because the
curvature predicted by general relativity at that
point is infinite. They are thought to exist at the
core of black holes.
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6.  Black holes are areas of intense gravitational
pressure. The pressure is thought to be so intense
that finite matter is actually squished into infinite
density. These zones of infinite density are called
"singularities‖.
 After the initial appearance of our universe as
singularity, it apparently inflated (the "Big
Bang"), expanded and cooled - going from
very, very small and very, very hot, to the size
and temperature of our current universe.
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7.  The universe continues to
expand and cool to this
day and we are inside of
it: incredible creatures
living on a unique planet,
circling a beautiful star
clustered together with
several hundred billion
other stars in a galaxy
soaring through the
cosmos, all of which is
inside a universe which
appeared out of
nowhere. This is the Big
Bang theory. 7

8.  The Big Bang theory developed from observations of the
structure of the Universe and from theoretical
considerations.
 In 1912, Vesto Slipher measured the first Doppler shift of a
"spiral nebula" (spiral nebula is the obsolete term for spiral
galaxies), and soon discovered that almost all such
nebulae were receding from Earth. He did not grasp the
cosmological implications of this fact, and indeed at the
time it was highly controversial whether or not these
nebulae were "island universes" outside our Milky Way.
 Other scientists who contributed to the research of the
expanding universe include:
• Albert Einstein
• Alexander Friedmann
• Edwin Hubble
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9.  In 1915, Einstein predicted
that the universe is
expanding and he came
up with 10 field equations
to support his general
theory of relativity.
 However, since Einstein
believed in a static
universe, he modified his
equations and put in a
cosmological constant to
make the universe static.
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10.  10 years later,
Alexander Friedmann,
a Russian cosmologist
and mathematician,
read Einstein’s work
but thought that the
cosmological
constant was wrong.
So, he tried to solve
Einstein’s equations.
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11.  Alexander then derived the Friedmann
equations from Albert Einstein's equations of
general relativity, showing that the Universe
might be expanding in contrast to the static
Universe model advocated by Einstein at that
time.
 Friedmann’s math proposed two models:
• Closed Universe
• Open Universe
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12.  Closed Universe: According to Alexander, time
and space have a beginning and an end. They
both began with a big bang and will end when
gravity stops the universe and pulls everything
back into one point – the big squeeze. The
universe is finite and the expanding universe is
due to space expanding.
 Open Universe: According to this part of the
theory, the universe began with a big bang and
will continue to expand forever. Time and space
have no end.
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13.  In 1924, Edwin Hubble's
measurement of the great
distance to the nearest
spiral nebulae showed that
these systems were indeed
other galaxies.
 Hubble painstakingly
developed a series of
distance indicators using
the 100-inch (2,500 mm)
Hooker telescope at Mount
Wilson Observatory.
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14.  This allowed him to estimate distances to
galaxies whose red shifts had already been
measured, mostly by Slipher. In 1929, Hubble
discovered a correlation between distance and
recession velocity—now known as Hubble’s Law
or Hubble’s Constant (Ho).
 Hubble’s Law explained the rate at which the
universe is expanding and the constant (Ho) is
used to estimate the size of the universe
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15.  In the 1920s and 1930s almost every major
cosmologist preferred an eternal steady
state Universe and several complained that the
beginning of time implied by the Big Bang
imported religious concepts into physics.
 This objection was later repeated by supporters
of the steady state theory. This perception was
enhanced by the fact that one of the
originators of the Big Bang theory, Monsignor
Georges Lemaître, was a Roman Catholic priest.
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16.  Arthur Eddington agreed with Aristotle that the
universe did not have a beginning in time and
that matter is eternal. A beginning in time was
"repugnant" to him.
 Lemaître, however, said,
―If the world has begun with a single quantum, the
notions of space and time would altogether fail to
have any meaning at the beginning; they would
only begin to have a sensible meaning when the
original quantum had been divided into a sufficient
number of quanta. If this suggestion is correct,
the beginning of the world happened a little before
the beginning of space and time.‖
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17.  During the 1930s, other ideas were proposed
as non-standard cosmologies to explain
Hubble's observations, including the Milne
model, the oscillatory Universe (originally
suggested by Friedmann, but advocated by
Albert Einstein and Richard Tolman)and Fritz
Zwicky's tired light hypothesis.
 However, it was then criticized by supporters of
the steady state theory that if the universe was
really initially very hot as the Big Bang
suggests, we should be able to find some
remnant of this heat.
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18.  In 1965, Radio astronomers Arno Penzias and Robert
Wilson discovered a 2.725 degree Kelvin Cosmic
Microwave Background radiation (CMB) which pervades
the observable universe. This is thought to be the
remnant which scientists were looking for to support the
Big Bang Theory. Penzias and Wilson shared the Nobel
Prize for Physics for their discovery in 1978.
 Significant progress in Big Bang cosmology has been
made since the late 1990s as a result of advances
in telescope technology as well as the analysis of data
from satellites such as COBE, the Hubble Space
Telescope and WMAP. Cosmologists now have fairly
precise and accurate measurements of many of the
parameters of the Big Bang model, and have made the
unexpected discovery that the expansion of the Universe
appears to be accelerating.
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19.  Observations of distant galaxies show that these
objects are red shifted - the light emitted from
them has been shifted to longer wavelengths.
 This can be seen by taking a frequency
spectrum of an object and matching
the spectroscopic pattern of emission
lines or absorption lines corresponding
to atoms of the chemical elements interacting
with the light.
 These red shifts are uniformly isotropic,
distributed evenly among the observed objects
in all directions.
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20.  On the left is a spectrum
of the transmitted
frequency of light from a
star.
 The right spectrum is the
observed frequency of
the star from Earth.
 The spectral lines are
observed to be shifted
towards the red end.
 This shows that the star is
moving away from us
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21.  If the red shift is interpreted as
a Doppler shift, the
recessional velocity of the
object can be calculated.
 For some galaxies, it is possible
to estimate distances via
the cosmic distance ladder.
When the recessional
velocities are plotted against
these distances, a linear
relationship known as Hubble's
law is observed:
 v = H0D, where
• v is the recessional velocity of
the galaxy or other distant
object,
• D is the moving distance to the
object, and
• H0 is Hubble's constant. 21

22.  A Giant Explosion
 I’m sure that when I talk about the Big
Bang, many of you imagine a huge explosion (I
know I did!).
 Well, Experts say that there was no explosion;
there was (and continues to be) an expansion.
Rather than imagining a balloon popping and
releasing its contents, imagine a balloon
expanding: an infinitesimally small balloon
expanding to the size of our current universe.
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23.  Another misconception is that we tend to image the
singularity as a little fireball appearing somewhere in
space. According to the many experts
however, space didn't exist prior to the Big Bang. In
1968 and 1970, papers were published in which
Einstein's Theory of General Relativity was extended
to include measurements of time and space.
 According to calculations, time and space had a
finite beginning that corresponded to the origin of
matter and energy. The singularity didn't
appear in space; rather, space began inside of the
singularity. Prior to the
singularity, nothing existed, not
space, time, matter, or energy - nothing.
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24.  We have made a first attempt at explaining the
answers that science has revealed about our
universe. Our understanding of the Big Bang, the
first atoms and the age of the universe is
obviously incomplete. As time wears on, more
discoveries are made, leading to infinite
questions which require yet more answers.
Unsatisfied with our base of
knowledge, research is being conducted
around the world at this very moment to further
our minimal understanding of the unimaginably
complex universe.
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