Origin and Formation of the

Universe

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“I CAN” Statements Origin/Formation of the Universe

Identify and Compare the two theories of universe formation [L2]

Describe the evidences supporting the Big Bang Theory and universe expansion [L3]Abundance of light elementsDescribe the formation of Cosmic Background

RadiationSummarize the Doppler Effect and Define

Redshift Describe the possible fates of the Universe [L2]

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How do scientists know about Earth’s formation?

Scientists use direct observation and theoretical models to try to understand how the universe formed.

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Theories [models]of Universe Formation

Big Bang Theory

Steady State Theory

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The Big Bang Theory

The most widely accepted theory for the formation of the Universe

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The Big Bang Theory

All matter was once compacted in a tiny, dense particle, smaller than a piece of dust.

The particle was compacted by extreme pressure and temperature

• an expansive event called the big bang instantaneously filled space with all matter and energy

Building a UniverseBuilding a Universe

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The Big Bang Theory

The Big Bang Theory The Big Bang Theory DOES NOT

state that the universe state that the universe was created from awas created from a“giant explosion”!!!“giant explosion”!!!

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The Big Bang Theory

10-43sec Initial, hyper-(super fast) expansion,

NOT an explosion! Matter and energy are propelled outward in all directions

10-32sec Hot soup of electrons, quarks and other particles

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The Big Bang Theory 10-6sec

Rapid cooling allows quarks to clump into protons and neutrons

3minutes protons and neutrons combine into atomic nuclei

300,000years electrons join nuclei to make atoms

(mostly Hydrogen and Helium); light (photons) is emitted

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The Big Bang Theory 1 billion years

Gravity brings together atoms of H and He forming giant clouds that will become galaxies.

1212Galaxies, families of billions of stars

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OUR galaxy, the Milky Way, a spiral galaxy

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Big Bang TimelineBig Bang Timeline

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The Big Bang Theory

Over the next 13.7 billion years, inflation continued and the universe cooled [-270C]

Inflation continues today, and according to the BBT, inflation should never end…

Consequences of the Big Bang

If the universe did come into existence through an expansive event. there should be some evidences:

The mix of the elements should be known

The universe should have a measurable Temp.

The universe should be expanding

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Abundance of Light Elements

Elemental composition of the present universe closely matches the predictions made by the BBT:

Nucleosynthesis ABB

Present day

76% Hydrogen 73% Hydrogen

24% Helium 26% Helium

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Big Bang “After Glow” In the early moments following the BB, the

universe was giving off large amounts of IR radiation (thermal energy) and visible light.

As the universe expanded, it cooled.

Weak radiation should be dispersed in all direction of space.

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Arno Penzias and Robert Wilson

Bell Labs’ radio telescope.

Early 1960s - Penzias and Wilsonare hired by Bell Labs to evaluatethe performance of the new radiotelescope to be used in trans-Atlantictelephone communications.

They found a small, unexplained signal regardless of the direction the telescope is pointed. It is notenough to be a problem, but theyare curious.

1964 - They become aware that thenoise in their telescope is the cosmicbackground radiation predicted bythe Big Bang theory.

COsmic Background Explorer In 1992, COBE announced a measurement that showed that the background radiation was ALMOST uniform

This measurement confirmed the temperature to be app. 2.73K

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image of the (extremely tiny) anisotropies in the cosmic background radiation

Remnant echo of the BB

THE BALLOON ANALOGY SPACE between galaxies is increasing

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Expanding Universe

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Cluster of galaxies do not increase in size, but the galaxies move further apart

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In the 1920s, Edwin Hubble determines that the galaxies are: Moving away from the Earth

in all directions and The father away they are,

the faster they move outward

Hubble’s Law states that:as the distance increases, so does the velocity. This implies that the universe is UNIFORMELY expanding.

Edwin Hubble with his cat Nikolus Copernicus. (Colliers Magazine, 1949)

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Hubble used a phenomenon first discovered by the Austrian mathematician and physicist,

Christian Doppler (1803-53).

The The pitchpitch of a note is how high or of a note is how high or low it sounds. low it sounds. It depends on the frequency of the wave.It depends on the frequency of the wave. Higher the frequency of a sound wave, Higher the frequency of a sound wave,

shorter its wavelength, higher its pitch. shorter its wavelength, higher its pitch.

How was this known???

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As the police car approaches, the SW from its siren are compressed towards the observer.The intervals between waves diminish, which translates into an increase in frequency or pitch.

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Conversely as the police car recedes, the SW are stretched relative to the observer, causing the siren's pitch to decrease.

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By the change in pitch of the siren, you can determine if the car is coming nearer or speeding away.

A change in pitch results from a change/shift in the frequency of the sound waves is referred to as the DOPPLER EFFECT.

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Doppler Effect [Light]

As the light from a galaxy travels away from us, As the light from a galaxy travels away from us, the distance between us and that galaxy increases, the distance between us and that galaxy increases, thus light is “stretched” appearing redder. thus light is “stretched” appearing redder.

Red has a longer wavelength than BlueRed has a longer wavelength than Blue

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Red Shift and Blue Shift

The waves emitted by an object moving toward an observer are squeezed; its frequency appears to increase and is therefore said

to be blueshifted. (shorter wavelength)](shorter wavelength)]

In contrast, the waves emitted by an object moving away are stretched or redshifted. (shorter frequency, longer wavelength)(shorter frequency, longer wavelength)

Blueshifts and redshifts exhibited by stars, galaxies and gas clouds also indicate their

motions with respect to the observer.

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Hubble and RedshiftHe recorded emission spectra for distant

galaxies and stars, thenmatched spectroscopic pattern of emission

spectrum with particular element, and observed that spectra did not match up

with any known spectra, but appeared to be a SHIFTED hydrogen

emission spectrum

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RedshiftThis is hydrogen spectrum hereOn earth

Small shiftFar away

Large shiftVERY far away

The Universe is

EXPANDING

and

SPEEDING UP

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Galaxy’s velocity is proportional to its distance

galaxies that are twice as far from us move twice as fast

Every galaxy took the same amount of time to move from a common starting position to its current position

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Einstein lecturing on the General Theory of Relativity in Pasadena, California, 1932.

Albert Einstein developed the general theory of relativity (GTR) in 1915.It predicted that space had to be either expanding or contracting.Einstein was still a bit unsure about what he had come up with and thus believed this to be incorrect and changed his theory.

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Expansion of Space 1916 - Einstein’s general theory of relativity predicts that

space must be either expanding or contracting. Einstein does not believe this and tries to “fix” the theory.

1920s - Other astronomers and physicists show that all versions of the GTR require either the expansion or contraction of space.

1929 - Hubble’s Law. 1930 - Arthur Eddington explains Hubble’s Law as the

expansion of space as described by the GTR. 1930 - Einstein calls his not accepting his original theory

“the greatest blunder of my scientific career.”

STEADY-STATE THEORY

Infinite Universe Theory Infinite Universe Theory

No definite beginningNo definite beginning

The Universe is expanding, but it always The Universe is expanding, but it always looked, and will look the samelooked, and will look the same this implies that its density remains constantthis implies that its density remains constant

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STEADY-STATE UNIVERSESTEADY-STATE UNIVERSE

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The Future of the Universe

The rate of expansion of the universeis increasing.

The universe will continue to expand forever, as suggested by the BBT, and

stars making up the galaxies will age and die. as more stars die over billions of years, the

universe will eventually grow cold and dark OR

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The Future of the Universe

The expansion will slow down as new matter is “formed” [E=mC^2], and will eventually stop

It will begin to contract and collapse until the universe contracts back to a single point in a big crunch!

PULSATING (OSCILLATING) THEORY

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Big Theory Video