f Don Lincoln, Fermilab f

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When the Universe Was Young and Hot
Don LincolnFermilabf
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Hubble Telescope

• This image is taken of galaxies that are billions
  of light-years away. Light takes a very long
  time to travel to Earth.
• Consequently, this photograph is of the
  conditions that existed billions of years ago,
  just a billion years or so after the big bang.
• Astronomers have thus created a time machine
  of sorts.

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Ancient Greek Cosmology

• In the beginning there was an empty darkness. The
  only thing in this void was Nyx (Chaos), a bird
  with black wings. With the wind she laid a golden
  egg and for ages she sat upon this egg. Finally
  life began to stir in the egg and out of it rose
  Eros, the god of love. One half of the shell rose
  into the air and became the sky and the other
  became the Earth. Eros named the sky Uranus and
  the Earth he named Gaia. Then Eros made them fall
  in love.

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Familiar Cosmology

• In the beginning God created the heaven and the
  earth.
• And the earth was without form, and void and
  darkness was upon the face of the deep. And the
  Spirit of God moved upon the face of the waters.

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Modern Cosmology

• Approximately 15 billion years ago, all of the
  matter in the universe was concentrated at a
  single point
• A cataclysmic explosion (of biblical proportions
  perhaps?) called the Big Bang caused the matter
  to fly apart.

• In the intervening years, the universe has been
  expanding, cooling as it goes.

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Consequences of the Big Bang

• If the universe did come into existence through a
  cataclysmic explosion, there should be some
  evidence. Three forms which I will discuss are
• The universe should be expanding
• The universe should have a measurable
  temperature.
• The mix of the elements should be known.

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Doppler Effect

• The Doppler effect says that things moving away
  from you look redder than they would if they
  werent moving. Things moving towards you look
  more blue.

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Edwin Hubble

• Using the Doppler effect, Edwin Hubble discovered
  that objects that were further away move away
  faster (and, hence, were redder) than nearer
  objects.
• This discovery showed that the universe was
  expanding and still provides one of the best
  measurements of the age of the universe.

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Black Body Radiator

• A black body radiator is one which absorbs all
  light which is incident on it.
• Such a body can also emit light, if sufficiently
  hot.
• The universe should thus have a temperature and
  an afterglow.

Universe
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Afterglow From the Big Bang
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Afterglow From the Big Bang

• In 1964, while working at Bell Labs, Penzias and
  Wilson discovered a radio hiss that they couldnt
  make go away.
• They had (by accident!) discovered the remnant
  echo of the Big Bang
• The universe was shown to have a temperature of
  2.726K (-450 F)

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COsmic Background Explorer

• In 1992, COBE announced a measurement that showed
  that the background radiation was not quite
  uniform (although nearly so)
• This measurement records information
  approximately 300,000 years after the Big Bang

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Goldilocks Effect

• These three plots show three different effects,
  each 10 less than the one larger than it.
• You can see how seeing a small effect first
  requires removing the bigger one.

Full, 10, and 1
Full only
10 and 1
10 only
1
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Helium Abundance in the Universe

• At the late time (as we shall see) of 3 minutes
  in the history of the universe, atomic nuclei
  were created.
• Big Bang theory predicts that the relative
  abundances of hydrogen and helium were
• Hydrogen 76
• Helium 24
• Lithium 1 part per 1010

• Due to nuclear fusion in stars since the Big
  Bang, current abundances
• Hydrogen 73
• Helium 26
• Everything else 1

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Summary of Cosmologic Measurements

• The Big Bang theory is consistent with
  observations. Specifically
• Hubble Telescope can view the universe
  1,000,000,000 years after the Big Bang
• The COBE satellite can view the universe 300,000
  years after the Big Bang
• The Hydrogen/Helium ratio can view the universe
  3 minutes after the Big Bang
• To which a particle physicist replies.

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Thats cute
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No.really..its cute
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Whats so interesting about that?All the
interesting stuff is overby three minutes.The
universe was in a retirement home by then.
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The really interesting question isWhat
happened when the universe was young and hot?
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History of the Universe

• In the beginning, the universe was really,
  really, hot.
• Consequently, things looked very different in the
  beginning.

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Consider an Ice Cube

• Heat it and it
• Melts
• Boils
• Turns to steam
• H2O breaks up into hydrogen and oxygen atoms
• The electrons get ripped off the atoms and
  electrons and atomic nuclei scurry around
• Atomic nuclei get broken up into protons and
  neutrons
• Protons and neutrons get ripped apart into
  particles called quarks.

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The Big Question

• How do you get something as hot as it was during
  the Big Bang?
• Smash stuff together!!

Hot!
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E m c2
Energy is Matter Matter is Energy
Lots of energy makes lots of matter and vice
versa!!!!!!
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• At Fermilab, we collide elementary particles at
  unprecedented energies, routinely recreating the
  conditions fractions of a second after the Big
  Bang.

In the spring of 2001, we will resume operations
after a five year upgrade. We will push our
understanding of the universe even further back
in time. Its gonna be cool!
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What are we going to find?

• I dont know!

Supersymmetry, Higgs, Technicolor, particles
smaller than quarks, something unexpected?
If I knew, it wouldnt be any fun.
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Everything in the Universe

• Microwave radiation
• super clusters
• clusters
• galaxies
• stars
• planets
• people
• poodles
• pigeons
• pond scum
• politicians

From the primordial soup!
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Data-Model Comparison
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Data-Model Comparison