Recent Cosmological Discoveries: Questions

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Recent Cosmological Discoveries Questions
Answers
Scott Dodelson Theoretical Astrophysics Group,
Fermilab

• Princeton University Class of 1957

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Breakfast with a Seven Year Old
Scott to Ilana You really should study for your
spelling test. Ilana Why? I got most of them
right last time without studying. Scott Don't
you want to be the best you can be? Do you want
to be mediocre? Ilana What's 'mediocre'? Scott
Just like everyone else. Ilana That's what I
want to be just like everyone else. Scott You
don't want to be the best? Ilana You're not the
best. Scott I try to be the best. Pause
Ilana It's not working.

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The Spirit Searches EverythingKeeping Lifes
Questions
More than homo sapiens humans knowing, we are
humans questioning homo quarens. From the
beginning of human existence, these thoughts and
questions have been put in one form or another.
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Is all wholly relative?

• Rather than seeing things as they are, we see
  things as we are
• Contemporary physics, the concept of time, and
  even the elegance and apparent truths of
  mathematics are not discoveries of what is
  really there inherent in reality but
  constructs and projections of the human mind
  looking for patterns and rationality
• There are as many different woods and rivers as
  those who walk or swim
• But is all wholly relative? Is every
  interpretation of the same value? Is there no
  basis for shared understanding?

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The Universe is expanding
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Galaxies should be moving away from us, and the
farther they are, the faster they should move
Edwin Hubble (1929)

• Other civilizations even those in other
  galaxies see the same effect
• Einstein did not ask astronomers to measure this!

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Light Element Production
The early universe was hot and dense, hot enough
and dense enough to be an excellent nuclear
reactor
T0 corresponds to temperatures/energies so high
that we do not know the physical laws governing
behavior We understand the limits of our
knowledge
T One Second
T Two Minutes
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Light Element Production
Predictions
Observations 75 24 1 part in 10000 1 part in
100,000 1 part in a billion
Hydrogen 75 Helium 24 Helium-3 1 part
in 10000 Deuterium 1 part in 100,000 Lithium 1
part in a billion

• Other civilizations even those in other
  galaxies see the same effect
• The work of Alpher Bethe, Gamow (1948) was
  ignored for over ten years

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Cosmic Radiation
In 1960, Bell Labs (Holmdel, NJ) researchers
Penzias Wilson took an old radio antenna (which
was replaced by a satellite) and searched for
radio waves from the center of our galaxy.
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They found no excess from Galaxy

• But a signal that was identical no matter what
  direction the telescope was pointed!

They assumed it was due to
So they took steps to eliminate the white
dielectric material
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Meanwhile at a small school 30 miles to the west

• Robert Dicke, Peter Roll, and David Wilkinson
  were trying to find the radiation that should be
  left over from the universes hot early past.

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One day they received a phone call from Bell Labs
Well, boys, weve been scooped!
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Cosmic Radiation

• Other civilizations even those in other
  galaxies see the same effect
• Dicke had the technological ability to detect
  this in the late 1940s!

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Sound, not Light
In many religions Gods creativity and presence
to the world are intuited in terms of light that
is itself invisible and silentSteiner more often
refers to sound which he imagines to be akin to
the background radiation of creation Music,
above all is the unwritten theology.
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We see radiation today from last scattering
surface when the universe was just 400,000 years
old
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Small Anisotropies in the Cosmic Radiation
Hotter than average by about 1 part in 10,000
Cooler than average by about 1 part in 10,000
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Acoustic Oscillations

• Pressure of radiation acts against clumping
• If a region gets overdense, pressure acts to
  reduce the density restoring force

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Pattern can be decomposed into Fourier modes


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(No Transcript)
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What spectrum is produced by a stringed instrument
C string on a ukulele
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Compare the ukulele spectrum to the cosmic
radiation spectrum
KINGS I11 Then a great and powerful wind tore
the mountains apart and shattered the rocks
before the LORD, but the LORD was not in the
wind. After the wind there was an earthquake, but
the LORD was not in the earthquake. 12 After the
earthquake came a fire, but the LORD was not in
the fire. And after the fire came a gentle
whisper. 13 When Elijah heard it, he pulled his
cloak over his face and went out and stood at the
mouth of the cave.       Then a voice said to
him, "What are you doing here, Elijah?"
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Questions/Answers

• Science Questions, Religion Accepts Answers
• The Wall Street Journal, Mar 23, 2005
• Mr. Charles H. Townes is free to believe
  whatever he wants, but this particular belief is
  preposterous in the face of human history. The
  history of the relationship between science and
  religion is clear Science encourages us to ask
  questions religion encourages us to accept
  answers. Religion's "encouragement" has at times
  (including today in many parts of our world)
  included acts of horrific violencetheirs is a
  "holds barring" effort of extraordinary
  proportions. Elsewhere holds are barred in less
  extreme ways, but they are barred nonetheless.
  The day we experience a jihad or crusade
  demanding belief in the existence of DNA, maybe
  I'll change my mind

No! Science respects answers we are no longer
asking the same questions we asked 100 years ago.
Questions in religion persist answers tell us
more about the person than about the question.
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We are actively pursuing other questions

• Why is there not nothing?
• What is the universe made of?

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Why is the Universe accelerating?
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Acceleration is surprising
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Mystery has broad appeal
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To get acceleration in the context of general
relativity
Need substance whose energy density remains
roughly constant as the universe expands
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Energy seems to be associated with empty space
These quantum mechanical fluctuations give the
vacuum an energy perhaps it is this energy that
is driving acceleration. I.e., Perhaps nothing is
something.
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When we try to calculate the energy of the vacuum

• The answer we get is too big by a factor of
• 1,000,000,000,000,000,000,000,000,000,000,000,000,
  000,000,000,000,000,000,000,000,000,000,000,000,00
  0,000,000,000,000,000,000,000,000,000,000,000,000,
  000,000,000

So, we are not done! But we believe that to
understand the universe on very large scales, we
need to improve our understanding of the physics
of the small.
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• What is the way to love and fear Him? By
  considering His works and His wonderful creations
  and seeing in them His wisdom.
• Maimonides, Code of Law
• I realize that I cannot just sit outside and
  observe. Each of us must participate in order to
  know We may drive by the woods looking at the
  trees and undergrowth through the car window. Or
  we may stop and hike into the woods for a very
  different experience.