Week 4 The Large Scale Universe

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Week 4 The Large Scale Universe

• Galaxies, Cosmology,
• The Theory of Everything

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Our Galaxy from the Inside
In visible light
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And in IR
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Our Galaxy in History

• Discovery
• 200 years ago astronomers assumed stars were
  evenly distributed through space!
• 100 years ago we were the center of a disk of
  stars

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Our Galaxy

• Variable stars were the trick
• RR Lyra and Cephid Henrietta Leavitt
• Instability Strip on H-R Diagram upper right
• Period Luminosity Relationship right
• Hubble in 1923 found Cephids in other galaxies
  same distance calculations but on an
  intergalactic scale!

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Our Galaxy pg 542-543

• Galactic Structure right top
• A Center (nuclear bulge) right bottom
• Disk
• Halo belowOpen clusters vs. Globular Clusters

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Galactic Structure

• Mass of a Galaxy
• Not only is the overall mass important, but the
  distribution of mass
• Disk orbits and Halo orbits lower left

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Dark Matter

• Keplerian motion is expected
• Falls apart at the outer edge!
• DARK MATTER
• A form of matter that does not react to E-M
  forces, or the Strong or Weak nuclear forces
  only gravity
• A Halo around the galaxy
• Extends as far as 7X the visible radius of the
  galaxy
• Contains 10-100X the mass of the visible galaxy
  in it!
• But we can see through it!
• Particles? Another force? A problem here and
  elsewhere.

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Dark Matter and Galaxies
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Galactic Structure

• Formation
• Similar to the Solar System Theory in principle
  right
• Age
• From oldest open clusters 7 billion years
• From globular clusters (Hipparcos observations)
  11 billion years
• Stars in the disk have metals (things heavier
  than Hydrogen and Helium), stars in the halo are
  almost entirely Hydrogen and Helium)

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Formation of Galaxies
Dark Matter a factor as well?
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Galactic Arms

• We are in the Orion-Cygnus Arm
• The next arm out is centered in Perseus (near
  Cassiopeia), the center of the galaxy is in
  Sagittarius
• Radio observations give us much of this structure
  (since light cant get through the dust)
• The arms are NOT solid objects held together by
  some force

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More Galactic Structure

• Spiral Arms make up the outer reaches of our
  Galaxy

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What makes arms?

• Best theory the Density Wave Theory- they are
  like sound waves/shock waves traveling through
  the disk
• O and B stars live their short lives before the
  wave passes (so we see the brightest stars
• BUT what starts the waves? How do you get
  branches? Unknown.

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More Galactic Structure

• The Nucleus
• Core region about as big as the full moon in our
  sky
• Massive Black Hole 2.7 million star mass!!
• Stars 860 AU away circle the core in 16 years!!!
• Event Horizon (Schwarzschild Radius) 13X larger
  than our sun in size.

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In the Core
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The Core of the Galaxy
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Galaxies in General

• Arms and Stars TYPES of Galaxies
• Elliptical Galaxies left
• Spiral Galaxies Barred Spirals center
• Irregular Galaxies lower right
• NEW! Dark Matter finding!!

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Spiral Galaxy Zoo Members
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Elliptical Galaxies
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And Irregular Galaxies
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An old idea

• Edwin Hubble Evolution Diagram
• E0 (round) to E7 (flat) elliptical
• S0 (part elliptical and part spiral) , Sa to Sc
  looser spiral
• SBa to SBc lower barred spiral
• Irr Irregular

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A better structure- by age alone
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Galactic Winds Young Galaxies?
More on thislater
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Galaxies in General

• Distances to the Galaxies
• Light years and parsecs are too small now Well
  use megaparsec (Mpc)
• One Mpc 3.26 million light years or 2x1019
  miles
• Cepheids can be seen for 200 Mpc (.6 billion
  light years the universe is about 14 billion
  light years in radius)

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Cepheid Variables
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Far Out Galaxies

• Beyond this we have to use the overall brightness
  of galaxies themselves (similar shape and detail)
• Supernova can help too (but are rare)
• LOOK BACK TIME (Moon 1.3 seconds, Sun 8
  minutes, Alpha Centauri 4 years, Andromeda
  Galaxy 2 million years, The edge of the
  universe 13.7 billion years)

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Out back in time
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Looking Out at Galaxies

• The most distant galaxies visible 3000 Mpc (10
  billion light years)
• The Hubble Law
• VrHd (Vr velocity of galaxy away from us, d
  distance in Mpc, H Hubble Constant
  (km/sec/Mpc)
• Newest results put H near 70-80 km/sec/Mpc
• 71 .4 km/sec/Mpc EVEN MORE RECENT from WMAP

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Hubble Velocity-Distance Relationship
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The Ladder of Distances
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Looking Out at Galaxies

• OTHER CRITTERS
• Colliding Galaxies

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Active Galactic Nuclei

• Galaxies with Active Nuclei wind again
• Pump out radio and X-ray radiation and jets (from
  the central Black Hole)
• Comes from Collisions newest theory

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Quasars

• Quasars
• Special active nuclei cores near the beginning
  of the universe (the furthest things visible in
  the universe)
• Moving away from us at a good fraction of the
  speed of light!!!
• Massive Black Holes
• Gravitational lens (Einstein)

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A good quasar!
Jets are common
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The discovery of quasars
Incredible Red Shift!!
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A distant quasar, core out-shines its disturbed
galactic arms
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Two lobes (in radio light) ejected from a
galactic core
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Artists conception of an active galactic nuclei
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AT the core of it massive black holes
Artists Interpretation
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How the massive Black Holes at the Galactic
Centers make the Jets
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How do we find massive galactic black holes?
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That takes us to the edge of stellar light. Lets
look at the universe itself!
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The Structure of the Universe

• The Structure of the Universe
• Clusters of Galaxies
• 2700 clusters within 4 billion light years
• Rich galaxy clusters gt1000 galaxies
• Poor galaxy clusters lt 1000 galaxies
• See the Hubble Deep Sky Image next two frames

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Ultra Deep Field Image(near Orion, abt. 1 square)
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Close-up HUDF
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But does it go on forever?Is the universe
infinite as Einstein assumed?
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The Structure of the Universe

• Olbers paradox - not an infinite universe

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The Universe as a Whole

• Assumptions of cosmology
• Homogeneity (distribution)
• Isotropy (looks the same)
• Universality (laws)
• Cosmological Principle (other observers would
  see the same stuff)

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Expansion

• Einstein and the geometry of Space Time
• The universe is expanding (Hubble et.al.)
• But not INTO anything lower left
• There is more empty space all the time (dense
  regions not expanding)
• Red Shift from expansion right
• Space time is Curved but how?

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Universal Geometry

• Finite but unbounded like a GLOBE favorite
  OUT
• Infinite and unbounded like a piece of paper -
  forever

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So is there an edge?

• Arno Penzias and Robert Wilson Bell
  Laboratories around 1965
• Detected the Cosmic BackgroundRadiation

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Cosmology- The Big Bang

• The Big Bang why is it the best theory?
• Primordial Background Radiation
• Echo or remains of early HIGH DENSITY time
• 2.7 Degree glow (remember Weins Law peak
  radiation and temperature) No emission lines
  since it was a compressed universe. Just
  temperature
• Present expansion and distribution of material -
  COBE
• Darkness between galaxies (Olber)

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WMAP map
NASA/WMAP Science Team
Average temp 2.725K (-455F) Red 0.0002
degrees warmer than the blue areas)
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Old vs. New
NASA/WMAP Science Team
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What WMAP sees
NASA/WMAP Science Team
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Breaking News

• Newest findings

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The most important PPT slide in 100 years

• WMAP Results
• Space all across the universe is flat, parallel
  lines never meet. The inflation theory underlying
  the Big Bang is correct. The universe continues
  infinitely far beyond our horizon.
• The universe is a mixture of 4.41 0.3 normal
  baryonic matter, 21.4 2.7 dark matter, 74.2
  3 dark energy (anti-gravity like force)
• Dark matter is cold not hot or warm.
  Neutrino limits set.
• The universe is 13.73 0.12 billion years old
  (best yet)
• Hubble Constant 70.1 1.3 km/sec/mpc
• Maximum Z (CBR) 10.8 1.4
• First stars turned on only 100-400 million years
  after big bang
• The large scale filaments of galaxies are frozen
  remains of the subatomic sized universe quantum
  fluctuations

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Make-up of the Universe
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What does a Flat Universe Mean?
What does the ant see on a surface that is really
a larger and larger sphere? What if the sphere is
nearly infinite in size?
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Cosmology The Big Bang

• Before the Big Bang?
• Another universe bounce?
• Our universe? (Finite and unbounded in time?)
• Depends on your favorite theory!

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The History of the Big Bang

• Nothing at first then it begins
• 1/10,000,000 ths of a second 1 trillion (1012)K
  , 5x1013 g/cm3)
• No matter- just energy (light)
• More matter than anti-matter made by a small
  margin (1 billion to one)
• 4 seconds all protons and neutrons made (cooled
  out)
• 2 minutes deuterium could form
• Nuclear reactions (like in stars) formed helium
• 30 minutes nuclear reactions ended (too cool now)
• 1 million years up to here a bright radiation
  dominated universe
• Atoms formed electrons could be caught T 3000K
  then TRANSPARENT! What COBE/WMAP see, the
  2.725K background radiation glow.

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Cosmology in the End

• The end of the universe?
• Critical Density
• 4x10-20 g/cm3
• Options
• Closed universe (Big Crunch someday)
• Open Universe (Heat Death) favored
• Oscillating Universe (bouncing re-creation)
• More on this later

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The makeup of the universe

• Dark Matter (2001 vs. 2005)
• Apparently 90-99 of the universe is Dark Matter
  (Now 21.4 2.7)
• The visible universe is only the tip of the
  iceberg! (Now 4.41 0.3)
• Dark Energy (Now the remaining 74.2 3)
• MACHOs massive Compact Halo Objects
  (Elliptical vs. Spiral)
• Gravitational lensing again
• A Quantum Universe Refinements of the Big Bang
  Theory
• Big Bang problems
• Flatness problem we are balanced on the
  open/closed boundary
• Isotropy- background radiation is too smooth 1
  part in 1000 perfect!
• The horizon problem- same temperature but no
  connection
• A Solution inflationary period makes it flat

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The Grand Unification Theory

• The Grand Unification Theory

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Another way to look at it
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Zero Point Energy and Freezing Forces
In cosmology, the vacuum energy is taken to be
the origin of the cosmological constant (dark
energy(?)). Experimentally, the zero-point energy
of the vacuum leads directly to the Casimir
effect, and is directly observable in nanoscale
devices.
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Putting it all together
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What is the CBR glow?

• It is the place back in time that we see the
  moment the universe became transparent.
• It was a solid then too thick or opaque before
  then we cant look farther.

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What else does a GUT help?

• Einstein's General Relativity and Quantum
  MechanicsDont Play Nicelyin Black Holes
• The singularity is the problem

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Re-fresh of Einstein and Gravity
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Different Gravitational Strengths
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GUTs

• Einstein et. al.
• All velocities are relative (Special Theory)
• Space and time are both aspects of the same thing
  Acceleration pull and gravitational pull are
  indistinguishable (General Theory)
• Energy and Matter are the same (Emc2)
• LATER- Space-time curvature is energy
  (Superstring theory)
• General Relativity and Quantum Mechanics DONT
  MIX! Within the atom either. Or do they?

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Super Duper Strings

• Superstring theory
• Four forces
• Strong Gluon
• Electromagnetic Photon
• Weak Weak gauge boson
• Gravity Graviton
• 3 Families of 4 particles each
• Electron, Electron neutrino, Up-quark, Down-quark
• Muon, Muon neutrino, Charm Quark, Strange Quark
• Tau, Tau neutrino, Top Quark, Bottom Quark

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Grand Unification II

• No room in the inn
• Strings make properties of the particles via
  their vibrations, but not enough room in 3 or 4
  dimensions
• More dimensions allow us to link the forces
• 10 needed (3 space, 1 time, 6 curled up space) to
  go to gravity
• Curled up below the sub-atomic scale previous
  page
• Calabi-Yau Shapes 10,000s which one? next
  page

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Curled up higher dimensions

• All these force particles and particles are made
  up of strings 10 dimensions curled up
• And this solves the infinities at the smallest
  scales Relativity and Quantum Mechanics can
  merge

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M-Theory

• The attempt to unify everything has lead down
  five roads so far
• M-Theory adds 1 more dimension 11
• Add one more dimension and you have a linking of
  the major theories! NOT FINISHED YET! 10-20 or
  100 years???
• The blind men and the elephant

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Other Uses for Strings?

• Cosmic Strings can cause gravitational lensing,
  can account for missing mass in universe
• Can create time travel
• Black Holes and Time Travel

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Gravitational Lensing
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The first great test of Einsteins Theory
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Lensing
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Einstein Ring
There is just one galaxy or quasar in the
background
Einstein Cross
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Time
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Stringsand Time
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A nod to branes

• Recent work (2003) has now bounded the higher
  dimensions by membranes (branes) that.
• p-branes (fill in your own of dimensions for
  p)
• We might be in a 4-D universe(3 space 1 time)
  that is next to another4-D universe separated by
  a 5th dimension
• The other 4-D universe is a shadow universe
  where gravity is rooted

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Parallel Universes

• There are many flavors

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The Other Yous

• Implications of an infinite flat universe
• 1011510 meters

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Quantum Weirdness

• One way that the math in the quantum world works
  well is if you add up ALL the POSSIBLE paths of a
  particle and see how they interact.
• So there might be a universe for every
  alternate possibility a universe where you are
  following out every choice you ever made and
  could have made.

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Freaky Interference again?

• This is another way to explain how particles can
  form this interference pattern, even if only one
  is let through the two slits per hour for weeks
  on end!

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Another possible Big Bang

• This leads us to the possibility that the big
  bang wasnt a tiny dot that expanded.
• The universe might have thinned out and thinned
  out until a parallel universe just fractions of
  an inch away could close and touch our universe.
• This would have filled the universe with a
  tremendous amount of energy that then would
  expand away. Just like the Big Bang! But
  different!
• Then end is different then a big expansion then
  another BANG! ? Next Slide!

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Here comes the brane

• LinkToAnimation

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Dark Energy and the END!

• The expansion rate of the universe is
  unsteadyand is accelerating.
• Eventually it will dominate the universe
  everything will be torn apart to photons then
  start over again.
• UPDATE Newest observations hint that normal
  expansion, not the tearing apart of even atoms,
  will occur.

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Another version of reality

• Information is King
• Closely realted to
• Information theory
• Quantum Gravity
• Loop Quantum Gravity

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Subtitled

• All the uses for a simple looking equation
• S k log w

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Redundancy

• We deal in information
• The information we work with is filled with
  redundancy.
• Language (think of static on the radio)
• Addresses (zip code 4)
• Internet protocols (duplex)
• Pictures/vision (can make out images through
  fog/static/snow/tall grass)
• Code breaking (look for rules in language)

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An example of a simple law of physics

• A Heat Engine
• Law of thermodynamics
• (Entropy Sk log W )

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The 3 Laws of Thermodynamics

• 1st law Energy cant be created or destroyed
  you cant win
• 2nd law The universe is moving towards an
  equilibrium you cant break even (no perpetual
  motion machines)
• 3rd law You cant cool anything to absolute
  zero there is always some information in any
  system you cant go broke.

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Entropy
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Entropy

• The number of ways you can organize things in a
  space.
• Bell curves!!
• These show up in-
• Grades
• People heights
• All over the natural world
• MUCH of the world is actuallya STASTISTICAL
  phenomena

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Bell Laboratories again

• Claude Shannon
• Asked How much information can you squeeze into
  a telephone line? What is the max?
• Think of Paul Revere red light, green light
• 1 light, 2 bits of information (land, or sea)
• 2 lights 4 (RRland, RGsea, GRtrain, GG
  car)

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Claude and beyond

• 3 lights (RRR land,
• RRG sea, RGRtrain, RGG air, GRR
  hovercraft, GRGspaceship,GGR teleportation,
  GGG on backs of evil angels) --- 8 bits!
• He found that when you have a question with N
  possible outcomes, you can answer it with only
  log N bits (letters).
• Or x log N - N number of sounds or bits,
  xthe maximum information you need to carry.

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Talk talk talk

• Everything done on a computer is done with
  letters of 0 and 1.
• Everything done in your genetic code is done with
  4 letters (GCAT).
• Our language 26 letters vast number of words!
• But the maximum information you can carry is log
  N, and Entropy k log W
• (k a constant, W the number of possible
  states)

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Entropy again

• So Entropy is really the measure of information!

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Entropy
There is only a few ways to have a perfect egg
a few bits, but many many many ways to have a
smashed egg.
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Enter Einstein

• Relativity says that nothing can go faster than
  the speed of light, and that the phenomena you
  observe depends on your viewpoint (more so at
  great speeds).
• Barn and pole relativity experiment

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Close the barn door!
Answer the view from the observer and the runner
is DIFFERENT relative! It all comes down to the
transmission of information!!!
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Back to the subatomic world

• Everything is quantized in the subatomic world
  where bits of matter are BOTH waves and particles
  (wave-particle duality remember?)

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Superposition a way to get wave/particle things

• Schrödinger's Cat
• Without infoon a subatomicparticle (or a
  cat),it becomes bothor all states at once!
• Alive AND Dead
• Observation makesthe probability cloudcollapse

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Information

• Again getting an observation of the cat,
  electron, nucleus, etc. collapses the probability
  wave for an instantall other possibilities go
  away.
• But all those other possibilities interact with
  the world! (Think of the two slit experiment
  again one photon a week the same pattern!!)

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The power of quantum computers

• If we leave the atom or electron or photon
  UNOBSERVED, then it remains in superposition
  (all possible states at once).
• Instead of an 8 bit computer, 16 bit, 32 bit, 64
  bit, you get every combination in-between (all
  partial bits as well).
• Can solve math problems that would take millions
  of years today in minutes. All calculations are
  performed at once!

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Back to the Universe now

• Remember the maximum amount of information you
  can transmit (contain in an area) is to its
  entropy.
• BUT Relativity and Quantum mechanics dont get
  along (remember? Unless string theory is correct
  unproven just promising)
• Another exampleQuantum Entanglement spooky
  action at a distance NO actual information
  transmitted!!
• Most of reality (that fact that it is even
  stable) is due to entanglement of particles with
  each other.

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Black Holes and Information

• The most extreme!
• Gravity becomes massive at the quantum scale.
• The surface area of a black hole k log W
• Entropy AND the maximum amount of information you
  can pack into a space! And it lives on the
  surface NOT the volume!
• The logical end of memory compacted-ness is a
  black hole.
• Its the ultimate memory stick!
• But can you get the information out?

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Reading Black Holes

• Hawking Radiation
• Virtual particles at the edge of the Event
  Horizon
• But can you get information out? Or is
  information destroyed beyond the event horizon?
• S. Hawking thinks that yes, maybe. But no one
  knows how or for sure currently.

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Gravity and Entropy

• It can reverse it locally (as can the other
  attractive forces).

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But this happens over time
So its time to talk about time
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Entropy and the Direction of Time
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The Arrow of Time

• Entropy seems to be responsible for the Direction
  of Time (the past is the past and the future is
  the future)
• In Relativity and Quantum Mechanics, there is no
  preferred direction of time. You can reverse the
  sign of t and the meaningful things still
  happen. Sometimes indistinguishable things
  (particles bouncing off one another)

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Sk logW

• This means that the universe was very special at
  the start of time.
• For us to still be running down (higher entropy)
  we had to be a universe of very LOW entropy at
  the start
• How did the universe get wound up or ordered at
  start?
• One possibility

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The history of the universe pt 1
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The history of the universe pt 2
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The secret is a very very specific, low entropy,
exact form of initial configuration of
material/energy in the sub-atom sized nugget that
started everything
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Back to parallel universes

• So we can draw a bubble (like an event horizon)
  around us say at the edge of the observable
  universe (our Hubble Bubble) and calculate how
  many states you can organize everything in (every
  particle in every spot).

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Information and the Universe

• Information is located completely on the surface
  of a black hole (area entropy max information
  storage).
• NOT the volume.
• Just like a hologram (3-D image in a 2-D picture)
  (Remember the branes?)
• So all the information in the 3-D universe can be
  encoded on a 2-D bubble.

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So there is a distance from us where this exact
arrangement of particles repeats!

• 1011510 meters
• Plenty of room for this in an infinite universe

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The Other Yous

• Implications of an infinite flat universe

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The Matrix Revisited

• The universe ACTS like memory in a computer.
  With multiple bits at every point that are
  empty space or a particle (or string with that
  vibrations for those phenomena) and rules that
  dictate how they communicate and interact just
  like a computer program.
• And there may be an infinite amount of memory for
  the universe and its version to be written on!

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Quantum Gravity

• Gravity (and all forces) are just communication
  between points of space (smaller than the plank
  scale 10-35m.
• To be tested by a satellite looking at cosmic
  raysquantum space time fabric a smearing out
  of distant light. A smooth space time fabric
  no smearing out.
• And well be looking for neutrinos from the big
  bang!

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Other Further Readings

• A New Kind of Science Stephen Wolfram All
  reality is tiny simple programs running on sets
  of points of space/time. Similar to fractal
  mathematics. Complexity comes from simplicity.
  ? Cellular automata
• Warped Passages Unraveling the Mysteries of the
  Universe's Hidden Dimensions (2005) by Lisa
  Randall
• The Fabric of the Cosmos Space, Time, and the
  Texture of Reality (2005) and The Elegant
  Universe (2004) by Brian Greene
• A Brief History of Time (2005) and The Universe
  in a Nutshell (2001) by Stephen Hawking

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There is much more being discovered all the time
stay tuned!

• General Public Places for this information
• (In order of easier to harder to read)
• Astronomy Magazine
• Sky and Telescope Magazine
• Scientific American
• Physics Today
• Nature and Science Magazines