The Universe - 2

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The Universe - 2

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Inflation

• When the strong force began separating from the
  electroweak force at the end of the GUT era,
  theorists hypothize that a major release of
  energy caused the Universe to expand at an
  exponential rate (at every step in time, the size
  of the Universe doubled). This is the Inflation.
• For instance, a region the size of a proton at
  10-35 sec would have grown to the size of a
  basketball by 10-33 sec.
• Although nothing can travel faster than light in
  space, space itself can expand faster than light
  this is what happened during Inflation.
• The tremendous expansion flattened the
  Universe and created, possibly, parallel
  Universes.

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Why do we need Inflation?
The light from the CMB has the same temperature
everywhere and in every direction. However, the
causally connected space had the size of a small
dot .
Thus, the CMB should appear with small
temperature variations, but it does not
Inflation!
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The Geometry of the Universe

• The Big Bang and early evolution of the Universe
  does not tell us anything about its geometry
• This is determined by how much mass there is in
  the Universe
• For all practical purposes, the mass in the
  Universe bends the space-time, pretty much like a
  Black Hole bends the space around itself.
• The geometry of the Universe determines its
  fate
• a closed Universe will at some point reverse its
  expansion into a contraction, and proceed towards
  a Big Crunch
• a flat or open Universe will expand forever.

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Whether the universe is open, close, or flat
depends on how much matter (and energy) it
contains

• For a flat Universe, the mean density (matter in
  a unit of volume) of the Universe at the present
  time must be about 10-26 kg/m3

It is determined by fundamental quantities, like
the Hubble constant and the Gravitational
constant ?c 3 H2 /
(8 ? G)
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The geometry of the Universe
Three possibilities Flat Universe, real and
apparent sizes are the same - (critical case,
stops at infinite times)
Closed Universe, objects appear larger than they
are (expands and re-collapses) Open Universe,
objects appear smaller than they are (expands
forever)
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The Universe as viewed in the Microwave by the
WMAP satellite
Contrast x 30,000
1 degree Universe Horizon
The angular sizes of the structure tells us about
the geometry of the Universe, because the real
sizes are known.
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The most prominent structures are about 1 degree,
meaning the Universe is flat
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Why is the Universe flat because of Inflation
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Formation of structures

• By structures we mean stellar clusters,
  galaxies and clusters of galaxies
• They were formed out of the fluctuations formed
  gravitationally by Dark Matter while the baryonic
  matter was still interacting with the light
  before the last recombination surface (z1100)

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The Universe as viewed in the Microwave by the
WMAP satellite
This small anisotropy ( 1/106) in the CMB,
emitted 300,000 years after the Big Bang,
represents the small fluctuation in the matter
distribution which provides the seed for the
structure formation in the universe.
Contrast x 30,000
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Structure Formation in the Universe
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Formation of the Large-Scale Structure
Due to gravity, acting on Dark Matter
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Big Questions

• What will be the fate of the universe?
• What are the dark matter and dark energy?
• What causes the big bang (inflation)?
• What, if any, of this should we believe?

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A summary of this course
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How do we combine geology and astronomy?

• Astrobiology is one of the most recent fields of
  Astronomy, and is still under development it
  combines the strengths of astronomy, biology,
  geology, climate science to investigate the
  possibility of life outside Earth
• 2. The investigation of Solar System objects
  requires geologists to be involved in the quest
  for instance, Prof. Hanners presentation talked
  about analyzing samples of comets. Geologists are
  the experts who know how best to perform such
  analyses. Not to forget Lunar and Mars
  explorations!

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What telescopes does NASA use to get the colorful
pictures of nearby and distant galaxies?
Spitzer Infrared
Hubble UV and Optical
Chandra X-ray
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What is the evidence for the existence of
anti-matter?

• Antimatter has been created in particle
  accelerators around the world its existence is
  well established.
• What we do not not is the origin of the slight
  primordial imbalance that produced the current
  matter Universe.

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What is the farthest thing/object we have
identified from Earth?
It really depends on what you mean by object.
The farthest we think we will ever be able to
see is the Cosmic Microwave Background. The
farthest galaxy, so far, is at redshift z7,
equivalent to an age of the Universe of less than
1 Gyr.
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The M.A.G.I.C. Gamma-ray Telescope team just
released the discovery that high-energy
gamma-rays from Mrk501 arrived with 4 minutes
delay relative to lower-energy radiation. What
does it mean?
The authors suggest that this is an effect of
quantum gravity (the high energy photons travel
more slowly through the quantum
foam). However, energy scales are much below
the Planck energy scale, which is needed to
test effects that happen at the level of
individual protons. And uncertainties in our
knowledge of gamma-ray-burst sources compounds to
raise some questions about the result.
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What is in the center of the Milky Way?
A black holes, plus a large number of stellar
clusters.
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Is the presence of a white dwarf in a binary
system shorten the life of the companion star?
No. Because the mass loss from the companion star
would happen anyway the difference is that
instead of being lost in space, it is accreted
onto the white dwarf.
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What is the chemical that makes the Neptunes
atmosphere appear blue?
Largely due to the methane in the atmosphere,
which absorbs the red light (but there could be
some yet unknown component in addition)
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If a comet collided into Jupiters Red Spot,
would it stop the storm?
It would really depend on the size (mass) and
speed of the comet, I.e., on the total energy
that an impact would impart to Jupiter.