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The Big Bang Theory:
Origin & Evolution of the Universe
Winner of the PowerPoint of the
Year Award (2013)
Newton’s Static Universe
• Universe is static and composed of an infinite
number of stars that are scattered randomly
throughout an infinite space.
• Universe is infinitely old and will exist forever
without any major changes.
• Time and Space are steady and independent
of one another and any objects in existence
within them.
Newton’s Error
• If the universe is as
how Newton describes,
then why is the sky
dark at night?
Olber’s Paradox
• If space is infinitely old with an infinite
number of stars, then in any line of sight in
any direction will eventually run into a star.
• Using this logic, the sky should be the
average brightness of all of these stars.
Einstein’s Relativity (1916)
• Gravity bends the
fabric of space time space and time are
influenced by whatever
matter (gravity) and
radiation are present.
Implications of Einstein’s Ideas
• Based on the general relativity
equations, Einstein predicted the
universe must be expanding.
• Einstein couldn’t make that
theoretical leap and theorized
that the universe’s expansion is
directly balanced by gravitational
contraction, thus yielding a static
universe.
• Without this idea of a
“cosmological constant”, Einstein
could’ve been the first to predict
that the universe is not static.
Edwin Hubble’s Discovery
• Hubble observed that the
wavelength of light coming
from distant galaxies was
experiencing redshift .
• This means the light source is
moving away from the
observer and increasing in
wavelength (doppler effect).
• The longer the light travels,
the more it gets redshifted.
Hubble’s Law
v = H0d
v = recessional velocity of the galaxy
H0 = Hubble constant
D = distance of galaxy to earth
• Galaxies are getting farther apart as time
progresses, therefore the universe is expanding.
– Not only is it expanding… it’s accelerating!
• The age of the universe can be derived from
Hubble’s constant:
For example, if H0 = 73 km/s*Mpc, then
T0 ~ 13.7 ± 0.2 byo
Origin of the Universe
• The universe began about 13.77 billion years ago.
• The Big Bang Theory states that, in the beginning, the
universe was all in one place.
• All of its matter and energy were squished into an
infinitely small point, a singularity.
• Then…. it exploded.
Cosmic Background Radiation
• Leftover thermal radiation
from the Big Bang.
• Uniform; from all directions.
• Weak microwaves that are
very close in energy to
predictions made by the Big
Bang Theory.
The Nebular Theory
• First proposed in 1734 by Emanuel Swedenborg.
• In cosmogony, the Nebular Theory is the currently
accepted explanation about how a Solar System can form.
The Nebular Theory
1. The tremendous amount of material blown out
by the big bang starts to group up
2. A large gas cloud (nebula) begins to condense
3. Most of the mass is in the center
The Nebular Theory
Small chunks
grow and collide,
eventually
becoming large
aggregates of gas
and solid chunks
Protostar
The Nebular Theory
Pictures from the Hubble Space Telescope show newborn
stars emerging from dense, compact pockets of interstellar
gas called evaporating gaseous globules
The Sun
• Huge mass and density rose temperatures in the Sun
to one million °C and thermonuclear fusion began.
• Fusion - combination of lightweight atomic nuclei into
heavier nuclei.
H atom + H atom = He atom + energy
Birth of the Solar System
The Age of the Solar System
Earth is ~ 4,570,000,000 years old
Meteorites give us access to debris left over
from the formation of the solar system
We can date meteorites using radioactive
isotopes and their decay products
The Universe is Highly Organized
• We have now discovered many planets orbiting
other stars.
• The processes that created our solar system
have also created an uncountable number of
other solar systems.
Finally Resulting In….
Possible Fates of the Universe
Open Universe: Expands Forever
• The universe will continue to expand. All
stars will die as the last of their energy is
released. Eventually, all matter will be
reduced to single atoms moving away
from each other. There will be nothing left.
Flat Universe: Static
• Gravitational attraction between objects
will cause the expansion of the universe
to slow and, eventually, come to a halt.
• Eventually the stars will burn out and it
will be a cold, cold place.
Closed Universe: Big Crunch
• Eventually, all matter and energy will
again condense into a single point,
possibly no larger than a dime. Another
Big Bang will occur and the formation of
the universe will begin all over again.
• Gravity will then begin to pull everything
back to the center of the universe.
In any case . . .
• Whatever happens to the
universe, we are pretty lucky
here on earth.
• We have the two main
requirements for life:
– Liquid water
– Protection from UV
radiation
• Perhaps elsewhere in the
universe, other planets or
moons do, too
Research Today
• Today, particle accelerators such as the
Large Hadron Collider are trying to replicate
conditions just after the Big Bang.
Remaining Questions
• What is dark matter?
• What is dark energy?
• Can dark energy and matter be detected and
studied in labs?
• What happened from the birth of the
universe, at the instance of the Big Bang, until
the end of the inflationary epoch?
• What is the ultimate fate of the universe?
• What caused the Big Bang?