expanding universe

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http://www.universeforum.org/einstein/ Our Expanding Universe Structure and Evolution of the Universe Workshop Our Expanding Universe: Humanity’s changing vision of the cosmos Presented by: Name, Affiliation Location and Date here

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Page 1: Expanding universe

http://www.universeforum.org/einstein/

Our Expanding Universe

Structure and Evolution of the Universe Workshop

Our Expanding Universe:Humanity’s changing vision of the cosmos

Presented by: Name, Affiliation

Location and Date here

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Our Expanding Universe

What is Cosmology?

The Study of the Universe: its structure, origin, evolution, and destiny

Our universal “world view”

Our cosmological model

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Our Expanding Universe

Universe models formed in many cultures

Cosmology through the ages…

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Our Expanding Universe

2nd Century: Claudius Ptolemy (Physics of Aristotle)Model: Earth-centered Cosmology

Big Idea: Different laws for Earth and the cosmos

Astronomy has seen 3 scientific revolutions in cosmology

16th Century: Nicolaus Copernicus (Physics of Newton) Model: Sun-centered Cosmology

Big Idea: Universal physics; same laws everywhere

20th Century: Edwin Hubble (Physics of Einstein)Model: Big Bang Cosmology

Big Idea: Universe is changing, evolving

Our View of the Cosmos - the story of scientific models

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Our Expanding Universe

…“the natural motion of the Earth ….is towards the center of the universe; that is the reason it is now lying at the center.”

Aristotle, On the Heavens

Earth-centered Cosmology: Claudius Ptolemy, 100-170 AD

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Our Expanding Universe

Prediction: Future planetary positions

Observation: retrograde motion of planets

Refine: epicycles

Success! For 1500 years

Testing the Earth-centered model

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Our Expanding Universe

Prediction: Phases of Venus

Observation: Full set of phases Crisis!

Testing the Earth-centered model

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Our Expanding Universe

Sun-centered Cosmology: Nicolaus Copernicus 1473-1543

“At rest, however, in the middle of everything is the Sun.”

Nicholaus Copernicus, de Revolutionibus

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Our Expanding Universe

Prediction: Future planetary positions

Observation: No better than Ptolemy

Refine: elliptical orbits (Johannes Kepler 1571-1630)

Testing the Sun-centered model

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Our Expanding Universe

Prediction: Observed shift in position of stars (parallax) as the earth Moves around the Sun.

Observation: No shift.

Crisis? No, but we had to wait until 1838 (Friedrich Bessel)

Testing the Sun-centered model

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Our Expanding Universe

Prediction: Sun at center of Cosmos

Observation: Sun is not at center of universe (1918)

Testing the Sun-centered model

Crisis!

Observation: The galaxy is not the entire universe (1923)

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Our Expanding Universe

Big Bang Cosmology: Albert Einstein (1879-1955)

“A human being is part of a whole, called by us ‘universe’, a part limited in time and space.”

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Our Expanding Universe

Prediction: The universe is expanding

Observation: Galaxies are moving apart from each other (1929)

Testing the Big Bang model

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Our Expanding Universe

Evidence for an expanding universe

The spectrum of hydrogen gas is the unique fingerprint of that element

Hydrogen lamp

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Our Expanding Universe

Evidence for an expanding universe

Orion Nebula

When we see a repeat of the pattern we saw in the lab, we know hydrogen is present

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Our Expanding Universe

Evidence for an expanding universe

We see the same repeating pattern of lines in

a galaxy, but displaced to the red

Galaxy UGC 12915

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Our Expanding Universe

Evidence for an expanding universe

The further the galaxy, the more the shift to the red

Galaxy UGC 12508

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Our Expanding Universe

Evidence for an expanding universe

Galaxy KUG 1750

The greater the red shift, the faster the galaxy is receding

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Our Expanding Universe

Evidence for an expanding universe

The red shift is caused by the expansion of space.

Galaxy KUG 1217

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Our Expanding Universe

Evidence for an expanding universe

The red shift is evidence for an expanding universe

Galaxy IRAS F09159

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Our Expanding Universe

Prediction: If the universe was denser, hotter, in past, we should see evidence of left-over heat from early universe. Observation: Left-over heat from the early universe. (Penzias and Wilson, 1965)

Testing the Big Bang model

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Our Expanding Universe

Prediction: A hot, dense expanding universe, should be predominantly hydrogen, helium.

The Sun: 74.5% H, 24% He by mass

Observation: Universe is ~75% hydrogen, ~25% helium by mass

Testing the Big Bang model

Cecilia Payne

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Our Expanding Universe

Prediction: An expanding universe is evolving over time. If we look at the early universe, it should appear different.

Observation: Distant galaxies less evolved, physically and chemically.

Testing the Big Bang model

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Our Expanding Universe

Observation: 90% of matter is an unknown form: Dark Matter.

Refine: A new and unknown form of matter exists. But its gravity works the same way, and its presence is needed to explain how the universe looks.

Testing the Big Bang model

Vera Rubin

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Our Expanding Universe

Observation: Expansion is accelerating.

Refine: Extra energy content.

A recent discovery and of unknown origin,the concept of Dark Energy is actually an integral part of Einstein’s theory of gravity.

Testing the Big Bang model

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Our Expanding Universe

Evidence for Dark Energy - supernovae as distance indicators - step 1

A dying star becomes a white dwarf.

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Our Expanding Universe

Evidence for Dark Energy - supernovae as distance indicators - step 2

The white dwarf strips gas from its stellar companion….

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Our Expanding Universe

Evidence for Dark Energy - supernovae as distance indicators - step 3

….and uses it to become a hydrogen bomb. Bang!

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Our Expanding Universe

Evidence for Dark Energy - supernovae as distance indicators - step 4

The explosion is as bright as an entire galaxy of stars….

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Our Expanding Universe

Evidence for Dark Energy - supernovae as distance indicators - step 5

…..and can be seen in galaxies across the universe.

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Our Expanding Universe

Dark Energy73%

Dark Matter23%

“Normal Matter”4%

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Our Expanding Universe

Conclusions

• Big Bang model describes our current understanding of the universe.

• New discoveries, such as dark matter and accelerating expansion (Dark Energy), lead us to refine our model, but there is no crisis in our understanding (yet).• Science is an ongoing process - forcing us to test our model through prediction and observation. The more tests it passes, the greater is our confidence in it.

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Our Expanding Universe

The Future of Cosmology: Beyond Einstein

• What powered the Big Bang?

• What is Dark Energy?

• How did the Universe begin?

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Our Expanding Universe

Credits

URL or program name here

http://www.universeforum.org/einstein/

Colliding galaxies: NASA & the Hubble Heritage Team (STScI)

Phases of Venus: Albert Van Helden

Star field: NASA/GSFC

Andromeda: Palomar Observatory, P. Challis, CfA

HGC 87: Gemini Observatory/GMOS-S

Galaxy cluster: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT

Orion nebula: MicroObservatory, SAO

Galaxy data: courtesy Emilio Falco, CfA

Comic microwave background: NASA/WMAP

Sun: SOHO/NASA/ESA

Cecilia Payne: President and Fellows of Harvard College

Early galaxies: NASA, Richard Griffiths/JHU, Medium Deep Survey Team

Edge-on galaxy: Bruce Hugo and Leslie Gaul, AdamBlock (KPNO Visitor Program), NOAO, AURA, NSF

Ring nebula: H. Bond et al., Hubble Heritage Team (STScI / AURA), NASA

White dwarf accretion: STScI, NASA

Supernova Remnant: NASA/ESA/JHU/R.Sankrit & W.Blair

Galaxy and supernova data: High-Z Supernova Search Team, HST, NASA

Composition of the universe: SAO

Spacecraft and Einstein probes: NASA

ALBERT EINSTEIN and related rights ™/© of The Hebrew University of Jerusalem, used under license. Represented by the Roger Richman Agency, Inc., www.albert-einstein.net

Please contact [email protected] for more information about non-credited historical images.

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Our Expanding Universe

Additional Credits

URL or program name here

http://www.universeforum.org/einstein/

This presentation was initially developed for the “Modeling the Universe” educator workshop by the Universe Education Forum and our NASA mission partners.

For additional information and activities related to the themes of this presentation, please visit the “Modeling the Universe” web site:

http://www.universeforum.org/mtu/

This collaboration is part of the education and public outreach program from NASA’s Science Mission Directorate.