Observing the Birth of the Universe'

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Observing the Birth of the Universe.
Rockefeller University, January 2007, L. Page
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How Big is the Universe?
Really big!
The Sun is 8 light minutes away.
The center of our Galaxy is 25,000 light years
away.
The Milky Way in infrared emission.
COBE/DIRBE satellite image
There are 1011 stars in our galaxy.
(roughly the number of cells in a finger)
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From Hubble
1011 Galaxies in Observable Universe
STScI/NASA Field Levay
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The Universe is Expanding
Hubble observed that the further away a galaxy is
the faster it is moving away.
Us
Galaxy
We are not (that!) special, all observers see the
same.
A neighbor
We should think about this as making space
since the Big Bang, not as an explosion in a
preexisting space. The Universe appears the same
from all vantages.
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The Universe is Infinite. We live in a Hubble
Patch
Ignore the expansion and imagine being able to go
anywhere in the whole universe instantaneously
Observable Universe or Hubble Patch
Edge of the observable universe
Diameter set by 2
(speed of light) x (age of universe)
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Because the Speed of Light is Finite, Telescopes
Are Like Time Machines
Still ignoring the expansion
We see distant objects when they were younger.
Edge of the observable universe
Younger
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Now Add The Expansion
Light from the edge was emitted when the
universe was much more compact. The expansion of
space stretches wavelengths.
Younger
Edge of the observable universe
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The Central Dogma of Cosmology
Surface of last scattering at decoupling.
Reionization
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Decoupling of the CMB
The universe expands and cools from its fiery
beginning.
When the temperature of the Universe is roughly
half the temperature of the Sun, atoms of
hydrogen can form.
Universe cools
Neutral atoms
Ionized plasma
This is called the epoch of decoupling and it
happened 379,000 years after the Big Bang.
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The Standard Cosmological Model
Surface of last scattering at decoupling.
Reionization
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The First Stars Turn on and Reionize the Universe
Brown is neutral hydrogen.
Blue is ionized hydrogen.
Simulation by Nick Gnedin (Fermi Lab)
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The Standard Cosmological Model
Surface of last scattering at decoupling.
Reionization
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Mark Subbarao SDSS Collaboration
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How Do We Measure the CMB?
With the expansion of the universe, the CMB has
cooled to -270 oC, or 2.725 oC above absolute
zero.
The CMB is about 1000 times cooler than the Sun
and so shines in the microwave regime.
Youve all detected the CMB!
TV Channel 69 broadcasts at 800 MHz
CMB approx 1 of TV noise!
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Wilkinson Microwave Anisotropy Probe.
Dave Wilkinson
(COBE announcement, 4/92)
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WMAP
A partnership between NASA/GSFC and Princeton
Science Team
NASA/GSFC Bob Hill Gary Hinshaw Al
Kogut Michele Limon Nils Odegard Janet Weiland Ed
Wollack
Johns Hopkins Chuck Bennett (PI) Ben Gold David
Larson
UCLA Ned Wright
Brown Greg Tucker
Chicago Stephan Meyer Hiranya Peiris
Princeton Jo Dunkley Norm Jarosik Lyman
Page David Spergel.
UBC Mark Halpern
CITA Olivier Dore Mike Nolta
Penn Licia Verde
UT Austin Eiichiro Komatsu
Microsoft Chris Barnes
Cornell Rachel Bean
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K Band, 22 GHz
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Ka Band, 33 GHz
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Q Band, 41 GHz
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V Band, 61 GHz
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W Band, 94 GHz
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(No Transcript)
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5º
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How do we get hot and cold patches?
W. Hu
Colder
Colder
Gravitational landscape--just like hills and
valleys.
Hotter
1 degree in angle
Spot size speed plasma ( ) travelsxage of
universe at decoupling
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Cosmic Paleontology
The fundamental mode acts as a fundamental
footprint or yardstick at the edge of the
observable universe.
Us
This allows us to determine the size of the
observable universe.
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From the standard yardstick, we can deduce the
distance to the edge of the universe.
Knowing this distance, and the speed of light, we
deduce that the age of the universe is
age of dinosaurs!
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Angular Power Spectrum
compression
Acoustic peaks
W. Hu
compression
rarefaction
Model
Fundamental mode
Cosmic variance
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Some Parameters of the Model
Basic model (with only six parameters) agrees
with virtually all cosmological measurements.
4.4
22.6
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These three plus the Hubble constant are 4 of the
parameters.
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The model is very strange
The dark energy has no foundation in any
fundamental theory of nature.
It is as though the vacuum has an energy
associated with it that drives the universe
apart, like antigravity.
Most feel that dark energy represents a missing
piece of theory as opposed to a substance.
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The Latest CMB Science
are parametrized
phenomenologically. We dont know why they are
what we observe.
However
Inflation-like models, based on field theories of
the tlt10-20s Universe, predict the gravitational
landscape to which the contents respond. The
prediction is that the slope of the power
spectrum is 5 smaller than the historic
phenomenological description.
WMAP has begun to observe this difference.
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Power spectrum
Physical size plasma speed X
age of universe at decoupling
Angular Power Spectrum.
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early in inflation
0.40
later in inflation
The overall slope of this spectrum is the new
handle on inflation.
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Large Angular Scale Polarization

• The formation of the first stars produces a
  primeval fog of free electrons that
• Rescatters CMB photons thereby reducing the
  anisotropy and confusing its interpretation.
• (2)Polarizes the CMB at large angular scales.

WMAP measures the degree of polarization (5th
parameter) to clean the anisotropy and uncover
the slope (6th parameter) of the primordial
quantum field.
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TT
TE
EE
Approx EE/BB foreground
BB inflation
BB r0.3
BB Lensing
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The Standard Cosmological Model
Abbreviated
At a very early time a quantum field impressed
on the universe a gravitational landscape. We
measure characteristics of this field.
This is literally a picture of a quantum field
from the birth of the universe.
Matter fell into the valleys to form eventually
structure. But only 1/6 of this matter is
familiar to us.
The dynamics of the universe is now driven not so
much by the matter but by an apparent
Dark Energy
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Thank You!
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WMAP Instrument drawing
FPA _at_ 90K
RXB _at_ 290K
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CMB alone tells us we are on the geometric
degeneracy line
closed
Geometric Degeneracy
open

WMAP3 only best fit LCDM
Assume flatness
Reduced
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From Wayne Hu
CMB Polarization
Polarization of the CMB is produced by Thompson
scattering of a quadrupolar radiation pattern.
E
2 deg
Whenever there are free electrons, the CMB is
polarized.
B
The polarization field is decomposed into E and
B modes.
Seljak Zaldarriaga
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Terminology E/B Modes
k
k
E-modes
B-modes
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K Band, 22 GHz
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Ka Band, 33 GHz
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Q Band, 41 GHz
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V Band, 61 GHz
CMB 6 uK
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W Band, 94 GHz