The Big Bang Theory

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The Big Bang Theory

• How the Universe Formed.

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Cosmology
The study of the nature and evolution of the
universe.
Not the study of cosmetics and beauty supplies.
Not the study of Bill Cosby
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Assumptions Made
Assumption 1 The universality of physical laws
-gt The laws of physics are the same
everywhere
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Assumptions Made
Assumption 1 The universality of physical
laws Assumption 2 The cosmos is homogeneous
-gt Matter and radiation are spread out
uniformly w/ no large gaps or bunches.
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Assumptions Made
Assumption 1 The universality of physical
laws Assumption 2 The cosmos is
homogeneous Assumption 3 The universe is
isotropic -gt same properties in all
directions -gt no center and no direction
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Assumptions Made
Assumption 1 The universality of physical
laws Assumption 2 The cosmos is
homogeneous Assumption 3 The universe is
isotropic
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Now Lets Create The Universe !!
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Imagine
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Imagine
NOTHING
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Imagine
NOTHING
Nothing to see !
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Imagine
NOTHING
Nothing to see ! Nothing to hear !
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Imagine
NOTHING
Nothing to see ! Nothing to hear ! Nothing to
feel !
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Imagine
NOTHING
Nothing to see ! Nothing to hear ! Nothing to
feel ! Nothing to think !
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No Matter !
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No Matter !
No Energy !
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No Matter !
No Energy !
No Time !
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No Pizza !!!!!!!!!
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(No Transcript)
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NOTHING
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Then, about 13.7 billion years ago, something
happened ..
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An infinitely small point of energy is formed. It
disrupts the nothingness and begins to
expand. This is where and when the universe
began. Energy and time are created, but no matter
!!!
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Primeval Fireball
The universe is in an extremely high state of
energy, with temperatures estimated to be greater
than 1032 K. It is just ?! hot !!!! But this
ball of energy quickly expands and cools.
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Heavy Particle Era
The temperature is greater than 1012 K Less than
0.000001 seconds after the Big Bang At these
temperatures photons collide to produce massive
particles and antiparticles, such as protons and
antiprotons.
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Heavy Particle Era
The temperature is greater than 1012 K Less than
0.000001 seconds after the Big Bang These
massive particles and antiparticles also collide
and annihilate each other producing more photons.
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Heavy Particle Era
The temperature is greater than 1012 K Less than
0.000001 seconds after the Big Bang At the end
of this era, the universe is a thick soup of
heavy particles, antiparticles and energy. The
most important particles present are the protons.
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Light Particle Era
The temperature is greater than 6x109 K Less than
6 seconds after the Big Bang Because of the
lower temperatures during this era, the photons
present cant produce anymore heavy particles.
These photons can collide to produce light
particles and antiparticles, like electrons and
positrons.
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Light Particle Era
The temperature is greater than 6x109 K Less than
6 seconds after the Big Bang During this era
protons and electrons interact to form neutrons.
Antiprotons and positrons interact in the same
way.
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Light Particle Era
The temperature is greater than 6x109 K Less than
6 seconds after the Big Bang Some of the neutrons
decay back into protons and electrons. The
neutrons which survive are very important for the
next era.
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Light Particle Era
The temperature is greater than 6x109 K Less than
6 seconds after the Big Bang At the end of this
era the universe consists of heavy and light
particles (protons electrons). The universe
also has neutrons.
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Light Particle Era
The temperature is greater than 6x109 K Less than
6 seconds after the Big Bang At the end of this
era the universe consists of heavy and light
particles (protons electrons). The universe
also has neutrons. The low temperatures dont
allow any more matter/antimatter pairs to form
from colliding photons and no more neutrons can
be formed.
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Nucleosynthesis Era
The temperature is around 109 K Less than 300
seconds after the Big Bang The neutrons which
remain react with the protons to form an isotope
of Hydrogen called Deuterium. (1 proton and 1
neutron)
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Nucleosynthesis Era
The temperature is around 109 K Less than 300
seconds after the Big Bang The neutrons which
remain react with the protons to form an isotope
of Hydrogen called Deuterium. (1 proton and 1
neutron) All neutrons either become part of the
Deuterium or decay.
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Nucleosynthesis Era
The temperature is around 109 K Less than 300
seconds after the Big Bang Deuterium fuses to
form Helium. At this point the total mass of the
Helium formed is about 25 the total mass of the
universe.
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Nucleosynthesis Era
The temperature is around 109 K Less than 300
seconds after the Big Bang Deuterium fuses to
form Helium. At this point the total mass of the
Helium formed is about 25 the total mass of the
universe. Some Tritium (Hydrogen with 2
neutrons), Lithium and Berylium also form.
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Nucleosynthesis Era
The temperature is around 109 K Less than 300
seconds after the Big Bang In the first 5 minutes
after the Big Bang, heavy and light particles and
antiparticles are formed.
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Nucleosynthesis Era
The temperature is around 109 K Less than 300
seconds after the Big Bang In the first 5 minutes
after the Big Bang, heavy and light particles and
antiparticles are formed. Neutrons are formed
from protons and electrons, these neutrons
combine with the protons to form the first stable
nuclei of atoms. (Note These atoms still have
not captured the electrons, too much energy)
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Nucleosynthesis Era
The temperature is around 3000 K About 1 million
years after the Big Bang At these low
temperatures the nuclei which have formed can now
capture electrons and become neutral.
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Nucleosynthesis Era
The temperature is around 3000 K About 1 million
years after the Big Bang At these low
temperatures the nuclei which have formed can now
capture electrons and become neutral. This allows
light and radiation to pass through the neutral
atoms and expand throughout the universe cooling
to around 2.7 K
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Matter Era
The temperature is less than 3000 K Over 1
million years after the Big Bang With the
radiation and matter freed from each other, the
pressures which kept the matter from clumping
together is now greatly reduced.
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Matter Era
The temperature is less than 3000 K Over 1
million years after the Big Bang With the
radiation and matter freed from each other, the
pressures which kept the matter from clumping
together is now greatly reduced. Matter is able
to clump together forming galaxies, stars, and
the Earth.
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Matter Era
The temperature is less than 3000 K Over 1
million years after the Big Bang With the
radiation and matter freed from each other, the
pressures which kept the matter from clumping
together is now greatly reduced. Matter is able
to clump together forming galaxies, stars, and
the Earth. We are still in this era.
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Evidence of the Big Bang
No human was present at the beginning of the
universe, so how do we know this is what happened
? What evidence is there ?
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Evidence of the Big Bang
We cant test our ideas by creating little
universes (although this would be really cool.)
What evidence is there ?
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Evidence of the Big Bang
To answer this question we must first recall how
science is done.
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Evidence of the Big Bang
To answer this question we must first recall how
science is done. Scientists first create a model
based on observations.
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Evidence of the Big Bang
To answer this question we must first recall how
science is done. Scientists first create a model
based on observations. Then scientists make
predictions based on these models.
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Evidence of the Big Bang
To answer this question we must first recall how
science is done. Scientists first create a model
based on observations. Then scientists make
predictions based on these models. Scientists
then try and verify these predictions
experimentally or observationally.
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Evidence of the Big Bang
Prediction The most abundant element in the
universe should be Hydrogen.
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Evidence of the Big Bang
Prediction The most abundant element in the
universe should be Hydrogen. Observation Although
we clearly cant test the entire universe, all
celestial objects we can see tell us that the
most abundant element in each is hydrogen.
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Evidence of the Big Bang
Prediction The concentration of Helium should be
greater than 25.
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Evidence of the Big Bang
Prediction The concentration of Helium should be
greater than 25. Observation Directly observing
evidence of helium is difficult, but when we can
measure its concentration in stars we find that
it ranges from 27 to 30 Helium.
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Evidence of the Big Bang
Prediction The universe should be expanding
Edwin Hubble
Vesto M. Slipher
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Evidence of the Big Bang
Prediction The universe should be
expanding Observation In 1928, Edwin Hubble and
Vesto M. Slipher, confirmed separately that the
universe is expanding. They used the Doppler Red
Shift of stars and galaxies to prove this.
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Evidence of the Big Bang
Prediction When the universe began, the four
fundamental forces were actually one force.
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Evidence of the Big Bang
Prediction When the universe began, the four
fundamental forces were actually one
force. Observation This hasnt been completely
proven, but there is an incredible amount of
symmetry between the forces, look at Coulombs
Law (Electrical Force) and Newtons Law of
Gravitation (Gravitational Force).
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Evidence of the Big Bang
Prediction When the universe began, the four
fundamental forces were actually one
force. Observation In 1983, at Cern Labs,
particles were slammed together in their
accelerator at extremely high temperatures and
the Electromagnetic Force and the Weak Force were
shown to be one force called the Electroweak
force.
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Evidence of the Big Bang
Direct Observation of the Visible Universe It
takes a finite amount of time for light to travel
a distance. In one second light travel about
300,000,000 meters.
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Evidence of the Big Bang
Direct Observation of the Visible Universe It
takes a finite amount of time for light to travel
a distance. In one second light travel about
300,000,000 meters. The distance light travels in
a year is called a light year (ly).
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Evidence of the Big Bang
Direct Observation of the Visible Universe It
takes a finite amount of time for light to travel
a distance. In one second light travel about
300,000,000 meters. The distance light travels in
a year is called a light year (ly). When we look
at objects, like stars and galaxies we are
actually looking into their past.
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Direct Observation of the Visible Universe

• It takes light from the Sun approximately 8.3
  minutes to reach the Earth
• This means that if we are looking at the Sun we
  see how it was 8.3 minutes ago. We are looking
  into the past.

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Direct Observation of the Visible Universe

• Alpha Centauri is 4.3 ly away.
• This means it takes light from this star 4.3
  years to reach us.
• We are looking 4.3 years into the past.

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Direct Observation of the Visible Universe

• The galactic center is 20,000 to 30,000 ly away.
• This means it takes light from the galactic
  center 20,000 to 30,000 years to reach us.
• We are looking 20,000 to 30,000 years into the
  past.

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Direct Observation of the Visible Universe

• The Andromeda galaxy is 2 million ly away.
• This means it takes light from this galaxy 2
  million years to reach us.
• We are looking 2 million years into the past.

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Direct Observation of the Visible Universe

• The Hydra Cluster is 3.6 billion ly away.
• This means it takes light from this cluster of
  galaxies 3.6 billion years to reach us.
• We are looking 3.6 billion years into the past.

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Direct Observation of the Visible Universe

• This galaxy is 13.2 billion ly away.
• This means it takes light from this galaxy 13.2
  billion years to reach us.
• We are looking 13.2 billion years into the past.
  Not real long after the Big Bang

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Evidence of the Big Bang
Background Radiation A crucial moment in the
creation of the universe was when the atoms that
were present became neutral and the radiation was
able to flow through it and expand with the
universe. This allowed matter to begin clumping
to form the structures we observe in the universe.
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Evidence of the Big Bang
Prediction The temperature of the background
radiation is 2.7 K
Robert Wilson
Arno Penzias
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Evidence of the Big Bang
Prediction The temperature of the background
radiation is 2.7 K Observation In 1964, Robert
Wilson Arno Penzias, detected this background
radiation and determined its temperature to be
3.5 K. For this they received the Nobel Prize in
Physics. Further experiments have found that
temperature to be 2.7 K.
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Map of the Background Radiation
In 2003 the WMAP satellite mapped the cosmic
background radiation, further confirming its
temperature to be 2.7 K.
This map also gave us great detail about the
early universe and it allowed us to refine the
age of the universe to 13.7 billion years.
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Map of the Background Radiation
This picture shows us how the universe looked
379,000 years after the Big Bang.
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Now Lets Destroy The Universe !!
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The End of the Universe
There are three possible futures for our
universe. Which one will be our fate depends on
the total mass of the universe or more
accurately, its density.
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The End of the Universe
It was Albert Einstein who calculated a critical
density for the universe.
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The End of the Universe
It was Albert Einstein who calculated a critical
density for the universe. This value is about
5 x 10-27 kg/m3 .
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The End of the Universe
It was Albert Einstein who calculated a critical
density for the universe. This value is about
5 x 10-27 kg/m3 . The fate of the
universe depends on whether or not the density is
above or below this value.
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The End of the Universe
The density of the universe is less than the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will not be
enough to stop the expansion of the universe.
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The End of the Universe
The density of the universe is less than the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will not be
enough to stop the expansion of the universe. The
universe will expand forever.
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The End of the Universe
The density of the universe is less than the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will not be
enough to stop the expansion of the universe. The
universe will expand forever. The overall
temperature of the universe will decrease
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The End of the Universe
The density of the universe is less than the
critical value of 5 x 10-27 kg/m3 The stars will
all eventually burn out and no new stars will
form.
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The End of the Universe
The density of the universe is less than the
critical value of 5 x 10-27 kg/m3 The stars will
all eventually burn out and no new stars will
form. Protons will eventually begin to decay.
This is when the matter era will end and the
universe will become just a soup of quarks and
other subatomic particles.
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The End of the Universe
The density of the universe is equal to the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will
ultimately stop the expansion of the universe.
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The End of the Universe
The density of the universe is equal to the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will
ultimately stop the expansion of the universe. An
equilibrium will be reached and the universe will
last forever in this state (it may or may not be
the matter era).
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The End of the Universe
The density of the universe is greater than the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will
ultimately stop the expansion and cause the
universe to collapse.
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The End of the Universe
The density of the universe is greater than the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will
ultimately stop the expansion and cause the
universe to collapse. The universe will return to
one point and time.
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The End of the Universe
The density of the universe is greater than the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will
ultimately stop the expansion and cause the
universe to collapse. The universe will return to
one point and time. Will the universe begin again
????
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The End of the Universe
The density of the universe is greater than the
critical value of 5 x 10-27 kg/m3 The
gravitational pull of the universe will
ultimately stop the expansion and cause the
universe to collapse. The universe will return to
one point and time. Will the universe begin again
????
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The End of the Universe
Currently scientists have determined the density
of the universe to be less than 5 x 10-27 kg/m3.
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The End of the Universe
Currently scientists have determined the density
of the universe to be less than 5 x 10-27
kg/m3. If this is true the universe will expand
forever.
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The End of the Universe
Currently scientists have determined the density
of the universe to be less than 5 x 10-27
kg/m3. If this is true the universe will expand
forever. BRRRRRRRRR !!!!!!!!
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The End of the Universe
Currently scientists have determined the density
of the universe to be less than 5 x 10-27
kg/m3. If this is true the universe will expand
forever. BRRRRRRRRR !!!!!!!! However the
discovery of dark matter could change the
ultimate fate of the universe.