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COSMOLOGY
Study of the structure, history, and fate of the Universe
THE ANCIENT UNIVERSE
THE MODERN UNIVERSE
In 1054, a star in the Taurus constellation underwent a
supernova. Centuries later, astronomers can observe the Crab
Nebula, the glowing remnant of the dead star.
A FLAT EARTH
GEOCENTRIC MODEL
or the importance of men
Aristotle
(384 BC – 322 BC)
Ptolemy
(c. AD 90 – c. AD168)
(300 years after Aristotle)
SKY OBSERVATION
HELIOCENTRIC MODEL REVISITED
HELIOCENTRIC MODEL
Copernicus
(1473 – 1543)
Tycho Brahe
(1546-1601)
Astronomical Sextant
Armillary Sphere
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Tycho Brahe’s Observatory
Tycho Brahe’s Instruments
THE TELESCOPE
SKY OBSERVATION
HELIOCENTRIC MODEL REVISITED
Kepler
(1571 –1630)
Galileo
(1564–1642)
Galileo’s first telescope
World’s Largest Telescope
Canary Islands
LAW OF GRAVITATION
GENERAL RELATIVITY
F = G M1 M2 / r2
G = 6.673 X 1011 N m2 /kg2
Newton
(1643 –1727)
mass attracts mass
Einstein
(1879–1955)
Nobel Prize 1921
2D representation of a 4D concept
Black Hole: infinite curvature of space-time,
attracts all surrounding material
Gravity's effect is apparent even at the largest scales: just as gravity keeps the Earth
orbiting the sun, it holds these two irregular galaxies M32 and M110 in orbit around
the larger Andromeda galaxy.
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1919 SOLAR ECLIPSE: PROVING GENERAL
RELATIVITY
EINSTEIN’S STATIC UNIVERSE
Eddington
1882 - 1944
Light bent by the curvature of Space-Time
BIG BANG THEORY
COMPILING THE EVIDENCE
EXPANSION OF THE UNIVERSE: HUBBLE’S LAW
v = H0 d
General Relativity
Cosmological Principle
CMB
Nucleosynthesis
Expansion of Universe
Edwin Hubble
(1889 –1953)
Evolution of Stars and Galaxies
EXPANSION OF THE UNIVERSE: REDSHIFT
EXPANSION OF THE UNIVERSE
Redshift
Absorption lines in the optical spectrum of a
supercluster of distant galaxies (right), as
compared to absorption lines in the optical
spectrum of the Sun (left). Arrows indicate
redshift. Wavelength increases up towards
the red and beyond (frequency decreases).
Causes galaxies to appear to be moving apart.
The size of the cube will change.
The galaxies inside the cube stay the same size.
The Big Bang is not an explosion IN space, it is an explosion OF space!
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NUCLEOSYNTHESIS OF ELEMENTS
EVOLUTION OF GALAXIES
The shape of galaxies 14 billion years, 9 billion years, 5 billion years,
and 2 billion years (from left to right) after the Big Bang. Notice how
galaxies dating from 2 billion years are irregular and blob-like, while
those from 9 billion years and onward are more regular spirals.
COSMOLOGICAL PRINCIPLE
NUCLEOSYNTHESIS OF ELEMENTS
The structure and chemical content of astronomical objects provides valuable
information about what the universe's conditions must have been like long
ago in order to account for currently observed elemental ratios.
isotropic
homogeneous
The universe has no center and expands in nothing!
An accretion disk forms during the birth of a star.
A forming galaxy
COSMIC MICROWAVE BACKGROUND
OBSERVATION OF THE UNIVERSE
Penzias and Wilson first detected CMB in 1965
at Bell Laboratories in New Jersey.
Penzias and Wilson
Nobel Prize 1968
Looking farther out in space is looking back in time!
COBE (launched in 1989): Cosmic Background Explorer
Mather and Smoot Nobel Prize 2006
WMAP: Wilkinson Microwave Anisotropy Probe (launched in 2001)
(childhood of universe at 380 000 years)
(shows germs of stars and galaxies, gives information about age, composition and form of
universe)
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ORIGINS OF THE CMB
CMB AND REDSHIFT
During the first 380,000 years after the Big Bang, the universe was opaque.
As the universe expanded and cooled, light and matter decoupled and the
universe became transparent.
The CMB is a perfect example of redshift.
The light first radiated from this process is the CMB.
UNDERSTANDING THE CMB MAP
THE PREDICTIVE POWER OF THE CMB
The CMB is one of the strongest pieces of evidence for the Big Bang model.
The Big Bang theory makes highly accurate predictions about the size and
types of anisotropies in the CMB as well as its nearly perfect blackbody
spectrum, all of which have been verified by experiment and observations.
The spherical map of the CMB translates to an oval
in the same way a globe translates to a familiar
oval map when flattened.
THE AGE OF THE UNIVERSE
CONSEQUENCES OF THE BIG BANG
From redshift data from distant galaxies and supernovae: 13.7 billion years old.
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THE VISIBLE UNIVERSE
INFLATION, EXPANSION, AND OUR GROWING VISIBLE UNIVERSE
The timeline of the Universe is not straight but curved like a bell,
reflecting alternating periods of acceleration and deceleration.
HISTORY OF UNIVERSE
FROM t=0 TO TODAY
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INFLATION
DARK MATTER: MISSING MASS IN THE UNIVERSE
THE FATE OF THE UNIVERSE
Hot Dark Matter (HDM)
• Low mass fundamental particles which can travel at relativistic velocities:
neutrino.
• Current theories about structure formation ruled out HDM candidates.
Cold Dark Matter (CDM)
• heavier fundamental particles, brown dwarf stars and primordial black holes.
• WIMPS (Weakly Interacting Massive Particles) are high mass particles which
only interact via gravity and the weak force.
• Extensions to the Standard Model incorporating supersymmetry predict the
existence of WIMPs, requiring that each known fundamental particle have a
heavier supersymmetric partner.
• WIMPs are the leading CDM candidates.
CURRENT RESEARCH
DARK ENERGY
HUBBLE 1990 (Discovery)
Images of the Universe
WMAP (2001)
Cosmic baby picture
Compton (1991-2000)
Gamma-Ray Observatory
CHANDRA 1999 (Columbia)
Oldest quasars
SPITZER 2003
Origins and processes of galactic,
stellar and planetary evolution
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FUTURE RESEARCH
UNANSWERED QUESTIONS
• Are there undiscovered laws of nature?
• Is there a Grand Unified Theory (GUT)?
• What is Dark Energy?
• What is Dark Matter?
• What happened before 10-44 seconds?
• Why are there so many different kinds of particles?
• Why did antimatter vanish?
When launched, the Supernova Acceleration Probe (SNAP) will study the
effects of dark energy by surveying distant type Ia supernovae and making
detailed measurements of weak gravitational lensing.
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