Transcript The Big Bang Theory - Warren County Public Schools

The Big Bang Theory (Part II)
The Evidence that Supports It
Mike Stuckey
Warren East High School
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 ?
Evidence of the Big Bang
We can’t test our ideas by creating
little universes (although this would
be really cool.)
What evidence is there ?
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.
Evidence of the Big Bang
Prediction
The most abundant element in the universe should
be Hydrogen.
Observation
Although we clearly can’t test the entire universe,
all celestial objects we can see tell us that the most
abundant element in each is hydrogen.
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.
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.
Edwin Hubble
Vesto M. Slipher
Doppler Effect for Light
When
aalight
sourcemoves
moves
When
light
source
When
a
light
source
moves
When
a
light
source
moves
away
When
a
light
source
moves
away
away
from
you,
the
light
away
from
the
light
away from you, the light it itit
from
you,
lightit it
emits
from
you,the
the light
emits
shiftsshifts
emits
shifts
toward
the
red
emits
shifts
toward
the
red
emits
shifts
toward
the
red
toward
the
red
spectrum.
This
is
toward
the
red
spectrum.
This
is
spectrum.
This
is
called
called
Red
Shift.
spectrum.
This
is
called
Red
spectrum.
This
is
called
called
RedRed
Shift.Shift.
Shift.
Red Shift.
Doppler Effect for Light
The galaxies that we observe exhibit the red
shift showing that they are moving away from
us.
This observation shows that the universe is
expanding!
This evidence supports the Big Bang Theory!
Evidence of the Big Bang
Prediction
When the universe began, the four fundamental
forces were actually one force.
The Fundamental Forces
Gravitational Force
Electromagnetic Force
Nuclear Strong Force
Weak Force
Evidence of the Big Bang
Prediction
When the universe began, the four fundamental
forces were actually one force.
Observation
This
completely
proven,
butslammed
there is an
In hasn’t
1983, atbeen
Cern
Labs, particles
were
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the high
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accelerator
extremely
look at Coulomb’s
and Newton’sForce
Law of
temperatures
and theLaw
Electromagnetic
and
Gravitation.
the Weak Force were
shown to be one force called
the Electroweak force.
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 distant stars or galaxies, we actually are seeing how
they looked at some time in the past.
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.
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.
Direct Observation of the Visible
Universe
• Betelgeuse is 1400 ly
away.
• This means it takes
light from this star
1400 years to reach us.
• We are looking 1400
years into the past.
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.
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.
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.
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
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.
Evidence of the Big Bang
Prediction
The temperature of the background radiation
should be 2.7 K
Observation
Robert
Wilson
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
Arno
have found that temperature
to be 2.7 K.
Penzias
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.
Map of the Background Radiation
This picture shows us how the universe
looked 379,000 years after the Big Bang.